diff --git a/packages/core/src/common/objects.ts b/packages/core/src/common/objects.ts
index 54e650adee82d..9375f36be16af 100644
--- a/packages/core/src/common/objects.ts
+++ b/packages/core/src/common/objects.ts
@@ -14,6 +14,27 @@
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
 
+export function deepClone<T>(obj: T): T {
+    if (!obj || typeof obj !== 'object') {
+        return obj;
+    }
+    if (obj instanceof RegExp) {
+        return obj;
+    }
+    // tslint:disable-next-line:no-any
+    const result: any = Array.isArray(obj) ? [] : {};
+    Object.keys(obj).forEach((key: string) => {
+        // tslint:disable-next-line:no-any
+        const prop = (<any>obj)[key];
+        if (prop && typeof prop === 'object') {
+            result[key] = deepClone(prop);
+        } else {
+            result[key] = prop;
+        }
+    });
+    return result;
+}
+
 export function deepFreeze<T>(obj: T): T {
     if (!obj || typeof obj !== 'object') {
         return obj;
diff --git a/packages/core/src/common/resource.ts b/packages/core/src/common/resource.ts
index 7fba8a9408c09..e2506cb27b431 100644
--- a/packages/core/src/common/resource.ts
+++ b/packages/core/src/common/resource.ts
@@ -18,7 +18,7 @@ import { injectable, inject, named } from 'inversify';
 import { TextDocumentContentChangeEvent } from 'vscode-languageserver-types';
 import URI from '../common/uri';
 import { ContributionProvider } from './contribution-provider';
-import { Event } from './event';
+import { Event, Emitter } from './event';
 import { Disposable } from './disposable';
 import { MaybePromise } from './types';
 import { CancellationToken } from './cancellation';
@@ -117,26 +117,52 @@ export class DefaultResourceProvider {
 
 }
 
+export class MutableResource implements Resource {
+    private contents: string;
+
+    constructor(readonly uri: URI, contents: string, readonly dispose: () => void) {
+        this.contents = contents;
+    }
+
+    async readContents(): Promise<string> {
+        return this.contents;
+    }
+
+    async saveContents(contents: string): Promise<void> {
+        this.contents = contents;
+        this.fireDidChangeContents();
+    }
+
+    protected readonly onDidChangeContentsEmitter = new Emitter<void>();
+    onDidChangeContents = this.onDidChangeContentsEmitter.event;
+    protected fireDidChangeContents(): void {
+        this.onDidChangeContentsEmitter.fire(undefined);
+    }
+}
+
 @injectable()
 export class InMemoryResources implements ResourceResolver {
 
-    private resources = new Map<string, Resource>();
+    private resources = new Map<string, MutableResource>();
 
     add(uri: URI, contents: string): Resource {
-        const stringUri = uri.toString();
-        if (this.resources.has(stringUri)) {
-            throw new Error(`Cannot add already existing in-memory resource '${stringUri}'`);
+        const resourceUri = uri.toString();
+        if (this.resources.has(resourceUri)) {
+            throw new Error(`Cannot add already existing in-memory resource '${resourceUri}'`);
         }
-        const resource: Resource = {
-            uri,
-            async readContents(): Promise<string> {
-                return contents;
-            },
-            dispose: () => {
-                this.resources.delete(stringUri);
-            }
-        };
-        this.resources.set(stringUri, resource);
+
+        const resource = new MutableResource(uri, contents, () => this.resources.delete(resourceUri));
+        this.resources.set(resourceUri, resource);
+        return resource;
+    }
+
+    update(uri: URI, contents: string): Resource {
+        const resourceUri = uri.toString();
+        const resource = this.resources.get(resourceUri);
+        if (!resource) {
+            throw new Error(`Cannot update non-existed in-memory resource '${resourceUri}'`);
+        }
+        resource.saveContents(contents);
         return resource;
     }
 
@@ -146,5 +172,4 @@ export class InMemoryResources implements ResourceResolver {
         }
         return this.resources.get(uri.toString())!;
     }
-
 }
diff --git a/packages/debug-nodejs/src/node/debug-nodejs-backend-module.ts b/packages/debug-nodejs/src/node/debug-nodejs-backend-module.ts
index b3c0d2c06916d..0d97442754b9e 100644
--- a/packages/debug-nodejs/src/node/debug-nodejs-backend-module.ts
+++ b/packages/debug-nodejs/src/node/debug-nodejs-backend-module.ts
@@ -16,7 +16,7 @@
 
 import { ContainerModule } from 'inversify';
 import { NodeDebugAdapterContribution, Node2DebugAdapterContribution } from './node-debug-adapter-contribution';
-import { DebugAdapterContribution } from '@theia/debug/lib/node/debug-model';
+import { DebugAdapterContribution } from '@theia/debug/lib/common/debug-model';
 
 export default new ContainerModule(bind => {
     bind(DebugAdapterContribution).to(NodeDebugAdapterContribution).inSingletonScope();
diff --git a/packages/debug-nodejs/src/node/node-debug-adapter-contribution.ts b/packages/debug-nodejs/src/node/node-debug-adapter-contribution.ts
index e7334958a4b86..756f070bf23ee 100644
--- a/packages/debug-nodejs/src/node/node-debug-adapter-contribution.ts
+++ b/packages/debug-nodejs/src/node/node-debug-adapter-contribution.ts
@@ -27,7 +27,6 @@ export const LEGACY_PORT_DEFAULT = 5858;
 
 @injectable()
 export class NodeDebugAdapterContribution extends AbstractVSCodeDebugAdapterContribution {
-
     constructor() {
         super(
             'node',
@@ -94,12 +93,10 @@ export class NodeDebugAdapterContribution extends AbstractVSCodeDebugAdapterCont
 
 @injectable()
 export class Node2DebugAdapterContribution extends AbstractVSCodeDebugAdapterContribution {
-
     constructor() {
         super(
             'node2',
             path.join(__dirname, '../../download/node-debug2/extension')
         );
     }
-
 }
diff --git a/packages/debug/src/browser/breakpoint/breakpoint-manager.ts b/packages/debug/src/browser/breakpoint/breakpoint-manager.ts
index 790cf00cdc49d..c5daf762c2515 100644
--- a/packages/debug/src/browser/breakpoint/breakpoint-manager.ts
+++ b/packages/debug/src/browser/breakpoint/breakpoint-manager.ts
@@ -40,7 +40,7 @@ export class BreakpointManager extends MarkerManager<SourceBreakpoint> {
         return marker && marker.data;
     }
 
-    getBreakpoints(uri: URI): SourceBreakpoint[] {
+    getBreakpoints(uri?: URI): SourceBreakpoint[] {
         return this.findMarkers({ uri }).map(marker => marker.data);
     }
 
@@ -64,6 +64,12 @@ export class BreakpointManager extends MarkerManager<SourceBreakpoint> {
         }
     }
 
+    deleteBreakpoint(uri: URI, line: number, column?: number): void {
+        const breakpoints = this.getBreakpoints(uri);
+        const newBreakpoints = breakpoints.filter(({ raw }) => raw.line !== line);
+        this.setBreakpoints(uri, newBreakpoints);
+    }
+
     enableAllBreakpoints(enabled: boolean): void {
         for (const uriString of this.getUris()) {
             let didChange = false;
diff --git a/packages/debug/src/browser/console/debug-console-session.ts b/packages/debug/src/browser/console/debug-console-session.ts
index 167f3e36f5d5c..0ff4ec9d5d312 100644
--- a/packages/debug/src/browser/console/debug-console-session.ts
+++ b/packages/debug/src/browser/console/debug-console-session.ts
@@ -33,6 +33,9 @@ export class DebugConsoleSession extends ConsoleSession {
     readonly id = 'debug';
     protected items: ConsoleItem[] = [];
 
+    // content buffer for [append](#append) method
+    protected uncompletedItemContent: string | undefined;
+
     @inject(DebugSessionManager)
     protected readonly manager: DebugSessionManager;
 
@@ -125,6 +128,28 @@ export class DebugConsoleSession extends ConsoleSession {
         this.fireDidChange();
     }
 
+    append(value: string): void {
+        if (!value) {
+            return;
+        }
+
+        const lastItem = this.items.slice(-1)[0];
+        if (lastItem instanceof AnsiConsoleItem && lastItem.content === this.uncompletedItemContent) {
+            this.items.pop();
+            this.uncompletedItemContent += value;
+        } else {
+            this.uncompletedItemContent = value;
+        }
+
+        this.items.push(new AnsiConsoleItem(this.uncompletedItemContent, MessageType.Info));
+        this.fireDidChange();
+    }
+
+    appendLine(value: string): void {
+        this.items.push(new AnsiConsoleItem(value, MessageType.Info));
+        this.fireDidChange();
+    }
+
     protected async logOutput(session: DebugSession, event: DebugProtocol.OutputEvent): Promise<void> {
         const body = event.body;
         const { category, variablesReference } = body;
diff --git a/packages/debug/src/browser/debug-configuration-manager.ts b/packages/debug/src/browser/debug-configuration-manager.ts
index d8b9cabbe0e8f..b6109a1f280fe 100644
--- a/packages/debug/src/browser/debug-configuration-manager.ts
+++ b/packages/debug/src/browser/debug-configuration-manager.ts
@@ -28,10 +28,10 @@ import { EditorManager, EditorWidget } from '@theia/editor/lib/browser';
 import { MonacoEditor } from '@theia/monaco/lib/browser/monaco-editor';
 import { QuickPickService, StorageService } from '@theia/core/lib/browser';
 import { WorkspaceService } from '@theia/workspace/lib/browser/workspace-service';
-import { DebugService } from '../common/debug-service';
 import { DebugConfiguration } from '../common/debug-configuration';
 import { DebugConfigurationModel } from './debug-configuration-model';
 import { DebugSessionOptions } from './debug-session-options';
+import { DebugService } from '../common/debug-service';
 
 @injectable()
 export class DebugConfigurationManager {
diff --git a/packages/debug/src/browser/debug-frontend-application-contribution.ts b/packages/debug/src/browser/debug-frontend-application-contribution.ts
index 45334e137f418..aadd428506c55 100644
--- a/packages/debug/src/browser/debug-frontend-application-contribution.ts
+++ b/packages/debug/src/browser/debug-frontend-application-contribution.ts
@@ -16,14 +16,10 @@
 
 import { AbstractViewContribution, ApplicationShell, KeybindingRegistry } from '@theia/core/lib/browser';
 import { injectable, inject } from 'inversify';
-import { JsonSchemaStore } from '@theia/core/lib/browser/json-schema-store';
 import { ThemeService } from '@theia/core/lib/browser/theming';
-import { InMemoryResources, MenuModelRegistry, CommandRegistry, MAIN_MENU_BAR, Command } from '@theia/core/lib/common';
-import { DebugService } from '../common/debug-service';
+import { MenuModelRegistry, CommandRegistry, MAIN_MENU_BAR, Command } from '@theia/core/lib/common';
 import { DebugViewLocation } from '../common/debug-configuration';
-import { IJSONSchema } from '@theia/core/lib/common/json-schema';
 import { EditorKeybindingContexts } from '@theia/editor/lib/browser';
-import URI from '@theia/core/lib/common/uri';
 import { DebugSessionManager } from './debug-session-manager';
 import { DebugWidget } from './view/debug-widget';
 import { BreakpointManager } from './breakpoint/breakpoint-manager';
@@ -42,6 +38,8 @@ import { DebugKeybindingContexts } from './debug-keybinding-contexts';
 import { DebugEditorModel } from './editor/debug-editor-model';
 import { DebugEditorService } from './editor/debug-editor-service';
 import { DebugConsoleContribution } from './console/debug-console-contribution';
+import { DebugService } from '../common/debug-service';
+import { DebugSchemaUpdater } from './debug-schema-updater';
 
 export namespace DebugMenus {
     export const DEBUG = [...MAIN_MENU_BAR, '6_debug'];
@@ -267,9 +265,8 @@ ThemeService.get().onThemeChange(() => updateTheme());
 @injectable()
 export class DebugFrontendApplicationContribution extends AbstractViewContribution<DebugWidget> {
 
-    @inject(JsonSchemaStore) protected readonly jsonSchemaStore: JsonSchemaStore;
-    @inject(InMemoryResources) protected readonly inmemoryResources: InMemoryResources;
-    @inject(DebugService) protected readonly debugService: DebugService;
+    @inject(DebugService)
+    protected readonly debug: DebugService;
 
     @inject(DebugSessionManager)
     protected readonly manager: DebugSessionManager;
@@ -292,6 +289,9 @@ export class DebugFrontendApplicationContribution extends AbstractViewContributi
     @inject(DebugConsoleContribution)
     protected readonly console: DebugConsoleContribution;
 
+    @inject(DebugSchemaUpdater)
+    protected readonly schemaUpdater: DebugSchemaUpdater;
+
     constructor() {
         super({
             widgetId: DebugWidget.ID,
@@ -336,43 +336,8 @@ export class DebugFrontendApplicationContribution extends AbstractViewContributi
                 this.openSession(session);
             }
         });
-        this.debugService.debugTypes().then(async types => {
-            const launchSchemaUrl = new URI('vscode://debug/launch.json');
-            const attributePromises = types.map(type => this.debugService.getSchemaAttributes(type));
-            const schema: IJSONSchema = {
-                ...launchSchema
-            };
-            const items = (<IJSONSchema>launchSchema!.properties!['configurations'].items);
-            for (const attributes of await Promise.all(attributePromises)) {
-                for (const attribute of attributes) {
-                    attribute.properties = {
-                        'debugViewLocation': {
-                            enum: ['default', 'left', 'right', 'bottom'],
-                            default: 'default',
-                            description: 'Controls the location of the debug view.'
-                        },
-                        'openDebug': {
-                            enum: ['neverOpen', 'openOnSessionStart', 'openOnFirstSessionStart', 'openOnDebugBreak'],
-                            default: 'openOnSessionStart',
-                            description: 'Controls when the debug view should open.'
-                        },
-                        'internalConsoleOptions': {
-                            enum: ['neverOpen', 'openOnSessionStart', 'openOnFirstSessionStart'],
-                            default: 'openOnFirstSessionStart',
-                            description: 'Controls when the internal debug console should open.'
-                        },
-                        ...attribute.properties
-                    };
-                    items.oneOf!.push(attribute);
-                }
-            }
-            items.defaultSnippets!.push(...await this.debugService.getConfigurationSnippets());
-            this.inmemoryResources.add(launchSchemaUrl, JSON.stringify(schema));
-            this.jsonSchemaStore.registerSchema({
-                fileMatch: ['launch.json'],
-                url: launchSchemaUrl.toString()
-            });
-        });
+
+        this.schemaUpdater.update();
         this.configurations.load();
         await this.breakpointManager.load();
     }
@@ -843,73 +808,3 @@ export class DebugFrontendApplicationContribution extends AbstractViewContributi
     }
 
 }
-
-// debug general schema
-const defaultCompound = { name: 'Compound', configurations: [] };
-
-const launchSchemaId = 'vscode://schemas/launch';
-const launchSchema: IJSONSchema = {
-    id: launchSchemaId,
-    type: 'object',
-    title: 'Launch',
-    required: [],
-    default: { version: '0.2.0', configurations: [], compounds: [] },
-    properties: {
-        version: {
-            type: 'string',
-            description: 'Version of this file format.',
-            default: '0.2.0'
-        },
-        configurations: {
-            type: 'array',
-            description: 'List of configurations. Add new configurations or edit existing ones by using IntelliSense.',
-            items: {
-                defaultSnippets: [],
-                'type': 'object',
-                oneOf: []
-            }
-        },
-        compounds: {
-            type: 'array',
-            description: 'List of compounds. Each compound references multiple configurations which will get launched together.',
-            items: {
-                type: 'object',
-                required: ['name', 'configurations'],
-                properties: {
-                    name: {
-                        type: 'string',
-                        description: 'Name of compound. Appears in the launch configuration drop down menu.'
-                    },
-                    configurations: {
-                        type: 'array',
-                        default: [],
-                        items: {
-                            oneOf: [{
-                                enum: [],
-                                description: 'Please use unique configuration names.'
-                            }, {
-                                type: 'object',
-                                required: ['name'],
-                                properties: {
-                                    name: {
-                                        enum: [],
-                                        description: 'Name of compound. Appears in the launch configuration drop down menu.'
-                                    },
-                                    folder: {
-                                        enum: [],
-                                        description: 'Name of folder in which the compound is located.'
-                                    }
-                                }
-                            }]
-                        },
-                        description: 'Names of configurations that will be started as part of this compound.'
-                    }
-                },
-                default: defaultCompound
-            },
-            default: [
-                defaultCompound
-            ]
-        }
-    }
-};
diff --git a/packages/debug/src/browser/debug-frontend-module.ts b/packages/debug/src/browser/debug-frontend-module.ts
index 91bce20b863d6..f1cb498838010 100644
--- a/packages/debug/src/browser/debug-frontend-module.ts
+++ b/packages/debug/src/browser/debug-frontend-module.ts
@@ -23,7 +23,13 @@ import { DebugPath, DebugService } from '../common/debug-service';
 import { WidgetFactory, WebSocketConnectionProvider, FrontendApplicationContribution, bindViewContribution, KeybindingContext } from '@theia/core/lib/browser';
 import { DebugSessionManager } from './debug-session-manager';
 import { DebugResourceResolver } from './debug-resource';
-import { DebugSessionContribution, DebugSessionFactory, DefaultDebugSessionFactory } from './debug-session-contribution';
+import {
+    DebugSessionContribution,
+    DebugSessionFactory,
+    DefaultDebugSessionFactory,
+    DebugSessionContributionRegistry,
+    DebugSessionContributionRegistryImpl
+} from './debug-session-contribution';
 import { bindContributionProvider, ResourceResolver } from '@theia/core';
 import { DebugFrontendApplicationContribution } from './debug-frontend-application-contribution';
 import { DebugConsoleContribution } from './console/debug-console-contribution';
@@ -35,6 +41,7 @@ import { InDebugModeContext } from './debug-keybinding-contexts';
 import { DebugEditorModelFactory, DebugEditorModel } from './editor/debug-editor-model';
 import './debug-monaco-contribution';
 import { bindDebugPreferences } from './debug-preferences';
+import { DebugSchemaUpdater } from './debug-schema-updater';
 
 export default new ContainerModule((bind: interfaces.Bind) => {
     bindContributionProvider(bind, DebugSessionContribution);
@@ -56,6 +63,7 @@ export default new ContainerModule((bind: interfaces.Bind) => {
     })).inSingletonScope();
     DebugConsoleContribution.bindContribution(bind);
 
+    bind(DebugSchemaUpdater).toSelf().inSingletonScope();
     bind(DebugConfigurationManager).toSelf().inSingletonScope();
 
     bind(DebugService).toDynamicValue(context => WebSocketConnectionProvider.createProxy(context.container, DebugPath)).inSingletonScope();
@@ -66,5 +74,8 @@ export default new ContainerModule((bind: interfaces.Bind) => {
     bindViewContribution(bind, DebugFrontendApplicationContribution);
     bind(FrontendApplicationContribution).toService(DebugFrontendApplicationContribution);
 
+    bind(DebugSessionContributionRegistryImpl).toSelf().inSingletonScope();
+    bind(DebugSessionContributionRegistry).toService(DebugSessionContributionRegistryImpl);
+
     bindDebugPreferences(bind);
 });
diff --git a/packages/debug/src/browser/debug-schema-updater.ts b/packages/debug/src/browser/debug-schema-updater.ts
new file mode 100644
index 0000000000000..7b18d64721af1
--- /dev/null
+++ b/packages/debug/src/browser/debug-schema-updater.ts
@@ -0,0 +1,144 @@
+/********************************************************************************
+ * Copyright (C) 2018 TypeFox and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { injectable, inject } from 'inversify';
+import { JsonSchemaStore } from '@theia/core/lib/browser/json-schema-store';
+import { InMemoryResources, deepClone } from '@theia/core/lib/common';
+import { IJSONSchema } from '@theia/core/lib/common/json-schema';
+import URI from '@theia/core/lib/common/uri';
+import { DebugService } from '../common/debug-service';
+
+@injectable()
+export class DebugSchemaUpdater {
+
+    @inject(JsonSchemaStore) protected readonly jsonSchemaStore: JsonSchemaStore;
+    @inject(InMemoryResources) protected readonly inmemoryResources: InMemoryResources;
+    @inject(DebugService) protected readonly debug: DebugService;
+
+    async update(): Promise<void> {
+        const types = await this.debug.debugTypes();
+        const launchSchemaUrl = new URI('vscode://debug/launch.json');
+        const schema = { ...deepClone(launchSchema) };
+        const items = (<IJSONSchema>schema!.properties!['configurations'].items);
+
+        const attributePromises = types.map(type => this.debug.getSchemaAttributes(type));
+        for (const attributes of await Promise.all(attributePromises)) {
+            for (const attribute of attributes) {
+                attribute.properties = {
+                    'debugViewLocation': {
+                        enum: ['default', 'left', 'right', 'bottom'],
+                        default: 'default',
+                        description: 'Controls the location of the debug view.'
+                    },
+                    'openDebug': {
+                        enum: ['neverOpen', 'openOnSessionStart', 'openOnFirstSessionStart', 'openOnDebugBreak'],
+                        default: 'openOnSessionStart',
+                        description: 'Controls when the debug view should open.'
+                    },
+                    'internalConsoleOptions': {
+                        enum: ['neverOpen', 'openOnSessionStart', 'openOnFirstSessionStart'],
+                        default: 'openOnFirstSessionStart',
+                        description: 'Controls when the internal debug console should open.'
+                    },
+                    ...attribute.properties
+                };
+                items.oneOf!.push(attribute);
+            }
+        }
+        items.defaultSnippets!.push(...await this.debug.getConfigurationSnippets());
+
+        const contents = JSON.stringify(schema);
+        try {
+            await this.inmemoryResources.update(launchSchemaUrl, contents);
+        } catch (e) {
+            this.inmemoryResources.add(launchSchemaUrl, contents);
+            this.jsonSchemaStore.registerSchema({
+                fileMatch: ['launch.json'],
+                url: launchSchemaUrl.toString()
+            });
+        }
+    }
+}
+
+// debug general schema
+const defaultCompound = { name: 'Compound', configurations: [] };
+
+const launchSchemaId = 'vscode://schemas/launch';
+const launchSchema: IJSONSchema = {
+    id: launchSchemaId,
+    type: 'object',
+    title: 'Launch',
+    required: [],
+    default: { version: '0.2.0', configurations: [], compounds: [] },
+    properties: {
+        version: {
+            type: 'string',
+            description: 'Version of this file format.',
+            default: '0.2.0'
+        },
+        configurations: {
+            type: 'array',
+            description: 'List of configurations. Add new configurations or edit existing ones by using IntelliSense.',
+            items: {
+                defaultSnippets: [],
+                'type': 'object',
+                oneOf: []
+            }
+        },
+        compounds: {
+            type: 'array',
+            description: 'List of compounds. Each compound references multiple configurations which will get launched together.',
+            items: {
+                type: 'object',
+                required: ['name', 'configurations'],
+                properties: {
+                    name: {
+                        type: 'string',
+                        description: 'Name of compound. Appears in the launch configuration drop down menu.'
+                    },
+                    configurations: {
+                        type: 'array',
+                        default: [],
+                        items: {
+                            oneOf: [{
+                                enum: [],
+                                description: 'Please use unique configuration names.'
+                            }, {
+                                type: 'object',
+                                required: ['name'],
+                                properties: {
+                                    name: {
+                                        enum: [],
+                                        description: 'Name of compound. Appears in the launch configuration drop down menu.'
+                                    },
+                                    folder: {
+                                        enum: [],
+                                        description: 'Name of folder in which the compound is located.'
+                                    }
+                                }
+                            }]
+                        },
+                        description: 'Names of configurations that will be started as part of this compound.'
+                    }
+                },
+                default: defaultCompound
+            },
+            default: [
+                defaultCompound
+            ]
+        }
+    }
+};
diff --git a/packages/debug/src/browser/debug-session-connection.ts b/packages/debug/src/browser/debug-session-connection.ts
index bf882e987a014..001325011d556 100644
--- a/packages/debug/src/browser/debug-session-connection.ts
+++ b/packages/debug/src/browser/debug-session-connection.ts
@@ -16,13 +16,11 @@
 
 // tslint:disable:no-any
 
-import { WebSocketConnectionProvider } from '@theia/core/lib/browser';
 import { DebugProtocol } from 'vscode-debugprotocol';
 import { Deferred } from '@theia/core/lib/common/promise-util';
 import { Event, Emitter, DisposableCollection, Disposable } from '@theia/core';
-import { WebSocketChannel } from '@theia/core/lib/common/messaging/web-socket-channel';
-import { DebugAdapterPath } from '../common/debug-service';
 import { OutputChannel } from '@theia/output/lib/common/output-channel';
+import { IWebSocket } from 'vscode-ws-jsonrpc/lib/socket/socket';
 
 export interface DebugExitEvent {
     code?: number
@@ -102,7 +100,7 @@ export class DebugSessionConnection implements Disposable {
     private sequence = 1;
 
     protected readonly pendingRequests = new Map<number, (response: DebugProtocol.Response) => void>();
-    protected readonly connection: Promise<WebSocketChannel>;
+    protected readonly connection: Promise<IWebSocket>;
 
     protected readonly requestHandlers = new Map<string, DebugRequestHandler>();
 
@@ -117,7 +115,7 @@ export class DebugSessionConnection implements Disposable {
 
     constructor(
         readonly sessionId: string,
-        protected readonly connectionProvider: WebSocketConnectionProvider,
+        protected readonly connectionFactory: (sessionId: string) => Promise<IWebSocket>,
         protected readonly traceOutputChannel: OutputChannel | undefined
     ) {
         this.connection = this.createConnection();
@@ -136,22 +134,18 @@ export class DebugSessionConnection implements Disposable {
         this.toDispose.dispose();
     }
 
-    protected createConnection(): Promise<WebSocketChannel> {
-        return new Promise<WebSocketChannel>(resolve =>
-            this.connectionProvider.openChannel(`${DebugAdapterPath}/${this.sessionId}`, channel => {
-                if (this.disposed) {
-                    channel.close();
-                } else {
-                    const closeChannel = this.toDispose.push(Disposable.create(() => channel.close()));
-                    channel.onClose((code, reason) => {
-                        closeChannel.dispose();
-                        this.fire('exited', { code, reason });
-                    });
-                    channel.onMessage(data => this.handleMessage(data));
-                    resolve(channel);
-                }
-            }, { reconnecting: false })
-        );
+    protected async createConnection(): Promise<IWebSocket> {
+        if (this.disposed) {
+            throw new Error('Connection has been already disposed.');
+        } else {
+            const connection = await this.connectionFactory(this.sessionId);
+            connection.onClose((code, reason) => {
+                connection.dispose();
+                this.fire('exited', { code, reason });
+            });
+            connection.onMessage(data => this.handleMessage(data));
+            return connection;
+        }
     }
 
     protected allThreadsContinued = true;
diff --git a/packages/debug/src/browser/debug-session-contribution.ts b/packages/debug/src/browser/debug-session-contribution.ts
index 9ddde5c04ef3b..9d7d0bbc88c35 100644
--- a/packages/debug/src/browser/debug-session-contribution.ts
+++ b/packages/debug/src/browser/debug-session-contribution.ts
@@ -14,7 +14,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
 
-import { injectable, inject } from 'inversify';
+import { injectable, inject, named, postConstruct } from 'inversify';
 import { MessageClient } from '@theia/core/lib/common';
 import { LabelProvider } from '@theia/core/lib/browser';
 import { EditorManager } from '@theia/editor/lib/browser';
@@ -25,6 +25,10 @@ import { BreakpointManager } from './breakpoint/breakpoint-manager';
 import { DebugSessionOptions } from './debug-session-options';
 import { OutputChannelManager, OutputChannel } from '@theia/output/lib/common/output-channel';
 import { DebugPreferences } from './debug-preferences';
+import { DebugSessionConnection } from './debug-session-connection';
+import { IWebSocket } from 'vscode-ws-jsonrpc/lib/socket/socket';
+import { DebugAdapterPath } from '../common/debug-service';
+import { ContributionProvider } from '@theia/core/lib/common/contribution-provider';
 
 /**
  * DebugSessionContribution symbol for DI.
@@ -46,10 +50,41 @@ export interface DebugSessionContribution {
     debugSessionFactory(): DebugSessionFactory;
 }
 
+/**
+ * DebugSessionContributionRegistry symbol for DI.
+ */
+export const DebugSessionContributionRegistry = Symbol('DebugSessionContributionRegistry');
+/**
+ * Debug session contribution registry.
+ */
+export interface DebugSessionContributionRegistry {
+    get(debugType: string): DebugSessionContribution | undefined;
+}
+
+@injectable()
+export class DebugSessionContributionRegistryImpl implements DebugSessionContributionRegistry {
+    protected readonly contribs = new Map<string, DebugSessionContribution>();
+
+    @inject(ContributionProvider) @named(DebugSessionContribution)
+    protected readonly contributions: ContributionProvider<DebugSessionContribution>;
+
+    @postConstruct()
+    protected init(): void {
+        for (const contrib of this.contributions.getContributions()) {
+            this.contribs.set(contrib.debugType, contrib);
+        }
+    }
+
+    get(debugType: string): DebugSessionContribution | undefined {
+        return this.contribs.get(debugType);
+    }
+}
+
 /**
  * DebugSessionFactory symbol for DI.
  */
 export const DebugSessionFactory = Symbol('DebugSessionFactory');
+
 /**
  * The [debug session](#DebugSession) factory.
  */
@@ -62,47 +97,45 @@ export class DefaultDebugSessionFactory implements DebugSessionFactory {
 
     @inject(WebSocketConnectionProvider)
     protected readonly connectionProvider: WebSocketConnectionProvider;
-
     @inject(TerminalService)
     protected readonly terminalService: TerminalService;
-
     @inject(EditorManager)
     protected readonly editorManager: EditorManager;
-
     @inject(BreakpointManager)
     protected readonly breakpoints: BreakpointManager;
-
     @inject(LabelProvider)
     protected readonly labelProvider: LabelProvider;
-
     @inject(MessageClient)
     protected readonly messages: MessageClient;
-
     @inject(OutputChannelManager)
     protected readonly outputChannelManager: OutputChannelManager;
-
     @inject(DebugPreferences)
     protected readonly debugPreferences: DebugPreferences;
 
-    protected traceOutputChannel: OutputChannel | undefined;
-
     get(sessionId: string, options: DebugSessionOptions): DebugSession {
-        let traceOutputChannel: OutputChannel | undefined;
-
-        if (this.debugPreferences['debug.trace']) {
-            traceOutputChannel = this.outputChannelManager.getChannel('Debug adapters');
-        }
+        const connection = new DebugSessionConnection(
+            sessionId,
+            () => new Promise<IWebSocket>(resolve =>
+                this.connectionProvider.openChannel(`${DebugAdapterPath}/${sessionId}`, channel => {
+                    resolve(channel);
+                }, { reconnecting: false })
+            ),
+            this.getTraceOutputChannel());
 
         return new DebugSession(
             sessionId,
             options,
-            this.connectionProvider,
+            connection,
             this.terminalService,
             this.editorManager,
             this.breakpoints,
             this.labelProvider,
-            this.messages,
-            traceOutputChannel,
-        );
+            this.messages);
+    }
+
+    protected getTraceOutputChannel(): OutputChannel | undefined {
+        if (this.debugPreferences['debug.trace']) {
+            return this.outputChannelManager.getChannel('Debug adapters');
+        }
     }
 }
diff --git a/packages/debug/src/browser/debug-session-manager.ts b/packages/debug/src/browser/debug-session-manager.ts
index f5e401868717d..9efe01e1cfd89 100644
--- a/packages/debug/src/browser/debug-session-manager.ts
+++ b/packages/debug/src/browser/debug-session-manager.ts
@@ -16,13 +16,13 @@
 
 // tslint:disable:no-any
 
-import { injectable, inject, named, postConstruct } from 'inversify';
-import { Emitter, Event, ContributionProvider, DisposableCollection, MessageService } from '@theia/core';
+import { injectable, inject, postConstruct } from 'inversify';
+import { Emitter, Event, DisposableCollection, MessageService } from '@theia/core';
 import { LabelProvider } from '@theia/core/lib/browser';
 import { EditorManager } from '@theia/editor/lib/browser';
-import { DebugService, DebugError } from '../common/debug-service';
+import { DebugError, DebugService } from '../common/debug-service';
 import { DebugState, DebugSession } from './debug-session';
-import { DebugSessionContribution, DebugSessionFactory } from './debug-session-contribution';
+import { DebugSessionFactory, DebugSessionContributionRegistry } from './debug-session-contribution';
 import { DebugThread } from './model/debug-thread';
 import { DebugStackFrame } from './model/debug-stack-frame';
 import { DebugBreakpoint } from './model/debug-breakpoint';
@@ -50,7 +50,6 @@ export interface DebugSessionCustomEvent {
 @injectable()
 export class DebugSessionManager {
     protected readonly _sessions = new Map<string, DebugSession>();
-    protected readonly contribs = new Map<string, DebugSessionContribution>();
 
     protected readonly onDidCreateDebugSessionEmitter = new Emitter<DebugSession>();
     readonly onDidCreateDebugSession: Event<DebugSession> = this.onDidCreateDebugSessionEmitter.event;
@@ -85,11 +84,8 @@ export class DebugSessionManager {
     @inject(DebugSessionFactory)
     protected readonly debugSessionFactory: DebugSessionFactory;
 
-    @inject(ContributionProvider) @named(DebugSessionContribution)
-    protected readonly contributions: ContributionProvider<DebugSessionContribution>;
-
     @inject(DebugService)
-    protected readonly debugService: DebugService;
+    protected readonly debug: DebugService;
 
     @inject(LabelProvider)
     protected readonly labelProvider: LabelProvider;
@@ -106,18 +102,18 @@ export class DebugSessionManager {
     @inject(MessageService)
     protected readonly messageService: MessageService;
 
+    @inject(DebugSessionContributionRegistry)
+    protected readonly sessionContributionRegistry: DebugSessionContributionRegistry;
+
     @postConstruct()
     protected init(): void {
-        for (const contrib of this.contributions.getContributions()) {
-            this.contribs.set(contrib.debugType, contrib);
-        }
         this.breakpoints.onDidChangeMarkers(uri => this.fireDidChangeBreakpoints({ uri }));
     }
 
     async start(options: DebugSessionOptions): Promise<DebugSession | undefined> {
         try {
             const resolved = await this.resolveConfiguration(options);
-            const sessionId = await this.debugService.create(resolved.configuration);
+            const sessionId = await this.debug.createDebugSession(resolved.configuration);
             return this.doStart(sessionId, resolved);
         } catch (e) {
             if (DebugError.NotFound.is(e)) {
@@ -132,7 +128,7 @@ export class DebugSessionManager {
             return options;
         }
         const { workspaceFolderUri } = options;
-        const resolvedConfiguration = await this.debugService.resolveDebugConfiguration(options.configuration, workspaceFolderUri);
+        const resolvedConfiguration = await this.debug.resolveDebugConfiguration(options.configuration, workspaceFolderUri);
         const configuration = await this.variableResolver.resolve(resolvedConfiguration);
         const key = configuration.name + workspaceFolderUri;
         const id = this.configurationIds.has(key) ? this.configurationIds.get(key)! + 1 : 0;
@@ -144,7 +140,7 @@ export class DebugSessionManager {
         };
     }
     protected async doStart(sessionId: string, options: DebugSessionOptions): Promise<DebugSession> {
-        const contrib = this.contribs.get(options.configuration.type);
+        const contrib = this.sessionContributionRegistry.get(options.configuration.type);
         const sessionFactory = contrib ? contrib.debugSessionFactory() : this.debugSessionFactory;
         const session = sessionFactory.get(sessionId, options);
         this._sessions.set(sessionId, session);
@@ -296,7 +292,7 @@ export class DebugSessionManager {
     }
 
     private doDestroy(session: DebugSession): void {
-        this.debugService.stop(session.id);
+        this.debug.terminateDebugSession(session.id);
 
         session.dispose();
         this.remove(session.id);
@@ -322,4 +318,17 @@ export class DebugSessionManager {
         return origin && new DebugBreakpoint(origin, this.labelProvider, this.breakpoints, this.editorManager);
     }
 
+    addBreakpoints(breakpoints: DebugBreakpoint[]): void {
+        breakpoints.forEach(breakpoint => {
+            this.breakpoints.addBreakpoint(breakpoint.uri, breakpoint.line, breakpoint.column);
+            this.fireDidChangeBreakpoints({ uri: breakpoint.uri });
+        });
+    }
+
+    deleteBreakpoints(breakpoints: DebugBreakpoint[]): void {
+        breakpoints.forEach(breakpoint => {
+            this.breakpoints.deleteBreakpoint(breakpoint.uri, breakpoint.line, breakpoint.column);
+            this.fireDidChangeBreakpoints({ uri: breakpoint.uri });
+        });
+    }
 }
diff --git a/packages/debug/src/browser/debug-session.tsx b/packages/debug/src/browser/debug-session.tsx
index dc97d9ce79fdb..bac3d931f0efb 100644
--- a/packages/debug/src/browser/debug-session.tsx
+++ b/packages/debug/src/browser/debug-session.tsx
@@ -17,7 +17,7 @@
 // tslint:disable:no-any
 
 import * as React from 'react';
-import { WebSocketConnectionProvider, LabelProvider } from '@theia/core/lib/browser';
+import { LabelProvider } from '@theia/core/lib/browser';
 import { DebugProtocol } from 'vscode-debugprotocol';
 import { Emitter, Event, DisposableCollection, Disposable, MessageClient, MessageType, Mutable } from '@theia/core/lib/common';
 import { TerminalService } from '@theia/terminal/lib/browser/base/terminal-service';
@@ -34,7 +34,6 @@ import URI from '@theia/core/lib/common/uri';
 import { BreakpointManager } from './breakpoint/breakpoint-manager';
 import { DebugSessionOptions, InternalDebugSessionOptions } from './debug-session-options';
 import { DebugConfiguration } from '../common/debug-common';
-import { OutputChannel } from '@theia/output/lib/common/output-channel';
 
 export enum DebugState {
     Inactive,
@@ -46,8 +45,6 @@ export enum DebugState {
 // FIXME: make injectable to allow easily inject services
 export class DebugSession implements CompositeTreeElement {
 
-    protected readonly connection: DebugSessionConnection;
-
     protected readonly onDidChangeEmitter = new Emitter<void>();
     readonly onDidChange: Event<void> = this.onDidChangeEmitter.event;
     protected fireDidChange(): void {
@@ -65,15 +62,12 @@ export class DebugSession implements CompositeTreeElement {
     constructor(
         readonly id: string,
         readonly options: DebugSessionOptions,
-        connectionProvider: WebSocketConnectionProvider,
+        protected readonly connection: DebugSessionConnection,
         protected readonly terminalServer: TerminalService,
         protected readonly editorManager: EditorManager,
         protected readonly breakpoints: BreakpointManager,
         protected readonly labelProvider: LabelProvider,
-        protected readonly messages: MessageClient,
-        protected readonly traceOutputChannel: OutputChannel | undefined,
-    ) {
-        this.connection = new DebugSessionConnection(id, connectionProvider, traceOutputChannel);
+        protected readonly messages: MessageClient) {
         this.connection.onRequest('runInTerminal', (request: DebugProtocol.RunInTerminalRequest) => this.runInTerminal(request));
         this.toDispose.pushAll([
             this.onDidChangeEmitter,
diff --git a/packages/debug/src/common/debug-configuration.ts b/packages/debug/src/common/debug-configuration.ts
index fe2b975c56a05..615716ce898f0 100644
--- a/packages/debug/src/common/debug-configuration.ts
+++ b/packages/debug/src/common/debug-configuration.ts
@@ -37,6 +37,11 @@ export interface DebugConfiguration {
      */
     [key: string]: any;
 
+    /**
+     * The request type of the debug adapter session.
+     */
+    request: string;
+
     /**
      * If noDebug is true the launch request should launch the program without enabling debugging.
      */
@@ -60,6 +65,6 @@ export interface DebugConfiguration {
 }
 export namespace DebugConfiguration {
     export function is(arg: DebugConfiguration | any): arg is DebugConfiguration {
-        return !!arg && 'type' in arg && 'name' in arg;
+        return !!arg && 'type' in arg && 'name' in arg && 'request' in arg;
     }
 }
diff --git a/packages/debug/src/node/debug-model.ts b/packages/debug/src/common/debug-model.ts
similarity index 96%
rename from packages/debug/src/node/debug-model.ts
rename to packages/debug/src/common/debug-model.ts
index 123da759cdea7..31bd1829461ad 100644
--- a/packages/debug/src/node/debug-model.ts
+++ b/packages/debug/src/common/debug-model.ts
@@ -23,10 +23,11 @@
 // Some entities copied and modified from https://github.com/Microsoft/vscode/blob/master/src/vs/workbench/parts/debug/common/debug.ts
 
 import * as stream from 'stream';
-import { Disposable, MaybePromise } from '@theia/core';
 import { WebSocketChannel } from '@theia/core/lib/common/messaging/web-socket-channel';
-import { DebugConfiguration } from '../common/debug-configuration';
+import { DebugConfiguration } from './debug-configuration';
 import { IJSONSchema, IJSONSchemaSnippet } from '@theia/core/lib/common/json-schema';
+import { Disposable } from '@theia/core/lib/common/disposable';
+import { MaybePromise } from '@theia/core/lib/common/types';
 
 // FXIME: break down this file to debug adapter and debug adapter contribution (see Theia file naming conventions)
 
@@ -151,7 +152,7 @@ export interface DebugAdapterContribution {
      * @param config The resolved [debug configuration](#DebugConfiguration).
      * @returns The [debug adapter executable](#DebugAdapterExecutable).
      */
-    provideDebugAdapterExecutable?(config: DebugConfiguration): MaybePromise<DebugAdapterExecutable | undefined>;
+    provideDebugAdapterExecutable?(config: DebugConfiguration): MaybePromise<DebugAdapterExecutable | undefined>;
 
     /**
      * Provides initial [debug configuration](#DebugConfiguration).
diff --git a/packages/debug/src/common/debug-service.ts b/packages/debug/src/common/debug-service.ts
index 3c18e0e5caf1f..705276c71c1fb 100644
--- a/packages/debug/src/common/debug-service.ts
+++ b/packages/debug/src/common/debug-service.ts
@@ -83,17 +83,12 @@ export interface DebugService extends Disposable {
      * @param config The resolved [debug configuration](#DebugConfiguration).
      * @returns The identifier of the created [debug adapter session](#DebugAdapterSession).
      */
-    create(config: DebugConfiguration): Promise<string>;
+    createDebugSession(config: DebugConfiguration): Promise<string>;
 
     /**
      * Stop a running session for the given session id.
      */
-    stop(sessionId: string): Promise<void>;
-
-    /**
-     * Stop all running sessions.
-     */
-    stop(): Promise<void>;
+    terminateDebugSession(sessionId: string): Promise<void>;
 }
 
 /**
diff --git a/packages/debug/src/node/debug-adapter-contribution-registry.ts b/packages/debug/src/node/debug-adapter-contribution-registry.ts
index b7616c870727a..bd9a30538e667 100644
--- a/packages/debug/src/node/debug-adapter-contribution-registry.ts
+++ b/packages/debug/src/node/debug-adapter-contribution-registry.ts
@@ -19,7 +19,7 @@ import { ContributionProvider } from '@theia/core';
 import { DebugConfiguration } from '../common/debug-configuration';
 import { DebuggerDescription, DebugError } from '../common/debug-service';
 
-import { DebugAdapterContribution, DebugAdapterExecutable, DebugAdapterSessionFactory } from './debug-model';
+import { DebugAdapterContribution, DebugAdapterExecutable, DebugAdapterSessionFactory } from '../common/debug-model';
 import { IJSONSchema, IJSONSchemaSnippet } from '@theia/core/lib/common/json-schema';
 
 /**
diff --git a/packages/debug/src/node/debug-adapter-factory.ts b/packages/debug/src/node/debug-adapter-factory.ts
new file mode 100644
index 0000000000000..fe9cd04c337a2
--- /dev/null
+++ b/packages/debug/src/node/debug-adapter-factory.ts
@@ -0,0 +1,103 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+// Some entities copied and modified from https://github.com/Microsoft/vscode-debugadapter-node/blob/master/adapter/src/protocol.ts
+
+import * as net from 'net';
+import { injectable, inject } from 'inversify';
+import {
+    RawProcessFactory,
+    ProcessManager,
+    RawProcess,
+    RawForkOptions,
+    RawProcessOptions
+} from '@theia/process/lib/node';
+import {
+    DebugAdapterExecutable,
+    CommunicationProvider,
+    DebugAdapterSession,
+    DebugAdapterSessionFactory,
+    DebugAdapterFactory
+} from '../common/debug-model';
+import { DebugAdapterSessionImpl } from './debug-adapter-session';
+
+/**
+ * [DebugAdapterFactory](#DebugAdapterFactory) implementation based on
+ * launching the debug adapter as separate process.
+ */
+@injectable()
+export class LaunchBasedDebugAdapterFactory implements DebugAdapterFactory {
+    @inject(RawProcessFactory)
+    protected readonly processFactory: RawProcessFactory;
+    @inject(ProcessManager)
+    protected readonly processManager: ProcessManager;
+
+    start(executable: DebugAdapterExecutable): CommunicationProvider {
+        const process = this.childProcess(executable);
+
+        // FIXME: propagate onError + onExit
+        return {
+            input: process.input,
+            output: process.output,
+            dispose: () => process.kill()
+        };
+    }
+
+    private childProcess(executable: DebugAdapterExecutable): RawProcess {
+        // tslint:disable-next-line:no-any
+        const isForkOptions = (forkOptions: RawForkOptions | any): forkOptions is RawForkOptions =>
+            !!forkOptions && !!forkOptions.modulePath;
+
+        const processOptions: RawProcessOptions | RawForkOptions = { ...executable };
+        const options = { stdio: ['pipe', 'pipe', 2] };
+
+        if (isForkOptions(processOptions)) {
+            options.stdio.push('ipc');
+        }
+
+        processOptions.options = options;
+        return this.processFactory(processOptions);
+    }
+
+    connect(debugServerPort: number): CommunicationProvider {
+        const socket = net.createConnection(debugServerPort);
+        // FIXME: propagate socket.on('error', ...) + socket.on('close', ...)
+        return {
+            input: socket,
+            output: socket,
+            dispose: () => socket.end()
+        };
+    }
+}
+
+/**
+ * [DebugAdapterSessionFactory](#DebugAdapterSessionFactory) implementation.
+ */
+@injectable()
+export class DebugAdapterSessionFactoryImpl implements DebugAdapterSessionFactory {
+
+    get(sessionId: string, communicationProvider: CommunicationProvider): DebugAdapterSession {
+        return new DebugAdapterSessionImpl(
+            sessionId,
+            communicationProvider
+        );
+    }
+}
diff --git a/packages/debug/src/node/debug-adapter-session-manager.ts b/packages/debug/src/node/debug-adapter-session-manager.ts
index d29a39b0fa24a..730104eb0211a 100644
--- a/packages/debug/src/node/debug-adapter-session-manager.ts
+++ b/packages/debug/src/node/debug-adapter-session-manager.ts
@@ -20,7 +20,7 @@ import { MessagingService } from '@theia/core/lib/node/messaging/messaging-servi
 
 import { DebugAdapterPath } from '../common/debug-service';
 import { DebugConfiguration } from '../common/debug-configuration';
-import { DebugAdapterSession, DebugAdapterSessionFactory, DebugAdapterFactory } from './debug-model';
+import { DebugAdapterSession, DebugAdapterSessionFactory, DebugAdapterFactory } from '../common/debug-model';
 import { DebugAdapterContributionRegistry } from './debug-adapter-contribution-registry';
 
 /**
diff --git a/packages/debug/src/node/debug-adapter.ts b/packages/debug/src/node/debug-adapter-session.ts
similarity index 65%
rename from packages/debug/src/node/debug-adapter.ts
rename to packages/debug/src/node/debug-adapter-session.ts
index 90e7ff3509af9..f559dd8b27a67 100644
--- a/packages/debug/src/node/debug-adapter.ts
+++ b/packages/debug/src/node/debug-adapter-session.ts
@@ -21,74 +21,13 @@
 
 // Some entities copied and modified from https://github.com/Microsoft/vscode-debugadapter-node/blob/master/adapter/src/protocol.ts
 
-import * as net from 'net';
-import { injectable, inject } from 'inversify';
-import { Disposable, DisposableCollection } from '@theia/core';
 import {
-    RawProcessFactory,
-    ProcessManager,
-    RawProcess,
-    RawProcessOptions,
-    RawForkOptions
-} from '@theia/process/lib/node';
-import {
-    DebugAdapterExecutable,
     CommunicationProvider,
     DebugAdapterSession,
-    DebugAdapterSessionFactory,
-    DebugAdapterFactory
-} from './debug-model';
+} from '../common/debug-model';
 import { DebugProtocol } from 'vscode-debugprotocol';
-import { WebSocketChannel } from '@theia/core/lib/common/messaging/web-socket-channel';
-
-/**
- * [DebugAdapterFactory](#DebugAdapterFactory) implementation based on
- * launching the debug adapter as separate process.
- */
-@injectable()
-export class LaunchBasedDebugAdapterFactory implements DebugAdapterFactory {
-    @inject(RawProcessFactory)
-    protected readonly processFactory: RawProcessFactory;
-    @inject(ProcessManager)
-    protected readonly processManager: ProcessManager;
-
-    start(executable: DebugAdapterExecutable): CommunicationProvider {
-        const process = this.childProcess(executable);
-
-        // FIXME: propagate onError + onExit
-        return {
-            input: process.input,
-            output: process.output,
-            dispose: () => process.kill()
-        };
-    }
-
-    private childProcess(executable: DebugAdapterExecutable): RawProcess {
-        // tslint:disable-next-line:no-any
-        const isForkOptions = (forkOptions: any): forkOptions is RawForkOptions =>
-            !!forkOptions && !!forkOptions.modulePath;
-
-        const processOptions: RawProcessOptions | RawForkOptions = { ...executable };
-        const options = { stdio: ['pipe', 'pipe', 2] };
-
-        if (isForkOptions(processOptions)) {
-            options.stdio.push('ipc');
-        }
-
-        processOptions.options = options;
-        return this.processFactory(processOptions);
-    }
-
-    connect(debugServerPort: number): CommunicationProvider {
-        const socket = net.createConnection(debugServerPort);
-        // FIXME: propagate socket.on('error', ...) + socket.on('close', ...)
-        return {
-            input: socket,
-            output: socket,
-            dispose: () => socket.end()
-        };
-    }
-}
+import { IWebSocket } from 'vscode-ws-jsonrpc/lib/socket/socket';
+import { DisposableCollection, Disposable } from '@theia/core/lib/common/disposable';
 
 /**
  * [DebugAdapterSession](#DebugAdapterSession) implementation.
@@ -96,9 +35,10 @@ export class LaunchBasedDebugAdapterFactory implements DebugAdapterFactory {
 export class DebugAdapterSessionImpl implements DebugAdapterSession {
 
     private static TWO_CRLF = '\r\n\r\n';
+    private static CONTENT_LENGTH = 'Content-Length';
 
     private readonly toDispose = new DisposableCollection();
-    private channel: WebSocketChannel | undefined;
+    private channel: IWebSocket | undefined;
     private contentLength: number;
     private buffer: Buffer;
 
@@ -115,7 +55,7 @@ export class DebugAdapterSessionImpl implements DebugAdapterSession {
         ]);
     }
 
-    async start(channel: WebSocketChannel): Promise<void> {
+    async start(channel: IWebSocket): Promise<void> {
         if (this.channel) {
             throw new Error('The session has already been started, id: ' + this.id);
         }
@@ -167,13 +107,22 @@ export class DebugAdapterSessionImpl implements DebugAdapterSession {
                     continue;	// there may be more complete messages to process
                 }
             } else {
-                const idx = this.buffer.indexOf(DebugAdapterSessionImpl.TWO_CRLF);
+                let idx = this.buffer.indexOf(DebugAdapterSessionImpl.CONTENT_LENGTH);
+                if (idx > 0) {
+                    // log unrecognized output
+                    const output = this.buffer.slice(0, idx);
+                    console.log(output.toString('utf-8'));
+
+                    this.buffer = this.buffer.slice(idx);
+                }
+
+                idx = this.buffer.indexOf(DebugAdapterSessionImpl.TWO_CRLF);
                 if (idx !== -1) {
                     const header = this.buffer.toString('utf8', 0, idx);
                     const lines = header.split('\r\n');
                     for (let i = 0; i < lines.length; i++) {
                         const pair = lines[i].split(/: +/);
-                        if (pair[0] === 'Content-Length') {
+                        if (pair[0] === DebugAdapterSessionImpl.CONTENT_LENGTH) {
                             this.contentLength = +pair[1];
                         }
                     }
@@ -199,17 +148,3 @@ export class DebugAdapterSessionImpl implements DebugAdapterSession {
         this.toDispose.dispose();
     }
 }
-
-/**
- * [DebugAdapterSessionFactory](#DebugAdapterSessionFactory) implementation.
- */
-@injectable()
-export class DebugAdapterSessionFactoryImpl implements DebugAdapterSessionFactory {
-
-    get(sessionId: string, communicationProvider: CommunicationProvider): DebugAdapterSession {
-        return new DebugAdapterSessionImpl(
-            sessionId,
-            communicationProvider
-        );
-    }
-}
diff --git a/packages/debug/src/node/debug-backend-module.ts b/packages/debug/src/node/debug-backend-module.ts
index fcdbd2d695f68..ff8475887bc46 100644
--- a/packages/debug/src/node/debug-backend-module.ts
+++ b/packages/debug/src/node/debug-backend-module.ts
@@ -23,14 +23,14 @@ import {
 import {
     LaunchBasedDebugAdapterFactory,
     DebugAdapterSessionFactoryImpl
-} from './debug-adapter';
+} from './debug-adapter-factory';
 import { MessagingService } from '@theia/core/lib/node/messaging/messaging-service';
 import { ConnectionContainerModule } from '@theia/core/lib/node/messaging/connection-container-module';
 import {
     DebugAdapterContribution,
     DebugAdapterSessionFactory,
     DebugAdapterFactory
-} from './debug-model';
+} from '../common/debug-model';
 import { DebugServiceImpl } from './debug-service-impl';
 import { DebugAdapterContributionRegistry } from './debug-adapter-contribution-registry';
 import { DebugAdapterSessionManager } from './debug-adapter-session-manager';
diff --git a/packages/debug/src/node/debug-service-impl.ts b/packages/debug/src/node/debug-service-impl.ts
index 8b8c648a5977d..001b9e9bfb723 100644
--- a/packages/debug/src/node/debug-service-impl.ts
+++ b/packages/debug/src/node/debug-service-impl.ts
@@ -35,7 +35,7 @@ export class DebugServiceImpl implements DebugService {
     protected readonly registry: DebugAdapterContributionRegistry;
 
     dispose(): void {
-        this.stop();
+        this.terminateDebugSession();
     }
 
     async debugTypes(): Promise<string[]> {
@@ -62,13 +62,13 @@ export class DebugServiceImpl implements DebugService {
     }
 
     protected readonly sessions = new Set<string>();
-    async create(config: DebugConfiguration): Promise<string> {
+    async createDebugSession(config: DebugConfiguration): Promise<string> {
         const session = await this.sessionManager.create(config, this.registry);
         this.sessions.add(session.id);
         return session.id;
     }
 
-    async stop(sessionId?: string): Promise<void> {
+    async terminateDebugSession(sessionId?: string): Promise<void> {
         if (sessionId) {
             await this.doStop(sessionId);
         } else {
diff --git a/packages/debug/src/node/vscode/vscode-debug-adapter-contribution.ts b/packages/debug/src/node/vscode/vscode-debug-adapter-contribution.ts
index fdb888ce71096..a9a8194f39a56 100644
--- a/packages/debug/src/node/vscode/vscode-debug-adapter-contribution.ts
+++ b/packages/debug/src/node/vscode/vscode-debug-adapter-contribution.ts
@@ -16,10 +16,11 @@
 
 import * as fs from 'fs-extra';
 import * as path from 'path';
-import { injectable, unmanaged } from 'inversify';
-import { DebugAdapterContribution, DebugAdapterExecutable } from '../debug-model';
+import { DebugAdapterExecutable, DebugAdapterContribution } from '../../common/debug-model';
 import { isWindows, isOSX } from '@theia/core/lib/common/os';
 import { IJSONSchema, IJSONSchemaSnippet } from '@theia/core/lib/common/json-schema';
+import { deepClone } from '@theia/core/lib/common/objects';
+import { injectable, unmanaged } from 'inversify';
 
 namespace nls {
     export function localize(key: string, _default: string) {
@@ -134,7 +135,7 @@ export abstract class AbstractVSCodeDebugAdapterContribution implements DebugAda
         const taskSchema = {}; // TODO
         const { configurationAttributes } = debuggerContribution;
         return Object.keys(configurationAttributes).map(request => {
-            const attributes: IJSONSchema = configurationAttributes[request];
+            const attributes: IJSONSchema = deepClone(configurationAttributes[request]);
             const defaultRequired = ['name', 'type', 'request'];
             attributes.required = attributes.required && attributes.required.length ? defaultRequired.concat(attributes.required) : defaultRequired;
             attributes.additionalProperties = false;
@@ -236,5 +237,4 @@ export abstract class AbstractVSCodeDebugAdapterContribution implements DebugAda
             args
         };
     }
-
 }
diff --git a/packages/java-debug/src/node/java-debug-adapter-contribution.ts b/packages/java-debug/src/node/java-debug-adapter-contribution.ts
index c74d7d3bc5444..c25c4740744d4 100644
--- a/packages/java-debug/src/node/java-debug-adapter-contribution.ts
+++ b/packages/java-debug/src/node/java-debug-adapter-contribution.ts
@@ -76,7 +76,6 @@ export class JavaDebugExtensionContribution extends AbstractVSCodeDebugAdapterCo
             path.resolve(this.extensionPath, javaExtPath)
         );
     }
-
 }
 
 @injectable()
diff --git a/packages/java-debug/src/node/java-debug-backend-module.ts b/packages/java-debug/src/node/java-debug-backend-module.ts
index 68d7cbb4348e3..ae3cca42c2805 100644
--- a/packages/java-debug/src/node/java-debug-backend-module.ts
+++ b/packages/java-debug/src/node/java-debug-backend-module.ts
@@ -16,8 +16,8 @@
 
 import { ContainerModule } from 'inversify';
 import { JavaExtensionContribution } from '@theia/java/lib/node';
-import { DebugAdapterContribution } from '@theia/debug/lib/node/debug-model';
 import { JavaDebugAdapterContribution, JavaDebugExtensionContribution } from './java-debug-adapter-contribution';
+import { DebugAdapterContribution } from '@theia/debug/lib/common/debug-model';
 
 export default new ContainerModule(bind => {
     /* explcit inTransientScope because it is very important, that
diff --git a/packages/plugin-ext/package.json b/packages/plugin-ext/package.json
index d693beee45203..3087f3d2541d2 100644
--- a/packages/plugin-ext/package.json
+++ b/packages/plugin-ext/package.json
@@ -14,11 +14,14 @@
     "@theia/plugin": "^0.3.18",
     "@theia/task": "^0.3.18",
     "@theia/workspace": "^0.3.18",
+    "@theia/debug": "^0.3.18",
     "decompress": "^4.2.0",
     "jsonc-parser": "^2.0.2",
     "lodash.clonedeep": "^4.5.0",
     "ps-tree": "1.1.0",
-    "vscode-uri": "^1.0.1"
+    "vscode-uri": "^1.0.1",
+    "uuid": "^3.2.1",
+    "vscode-debugprotocol": "^1.32.0"
   },
   "publishConfig": {
     "access": "public"
diff --git a/packages/plugin-ext/src/api/model.ts b/packages/plugin-ext/src/api/model.ts
index 25c59ba858bc3..ebb2a86a94dc9 100644
--- a/packages/plugin-ext/src/api/model.ts
+++ b/packages/plugin-ext/src/api/model.ts
@@ -407,3 +407,12 @@ export interface WorkspaceFolder {
     name: string;
     index: number;
 }
+
+export interface Breakpoint {
+    readonly enabled: boolean;
+    readonly condition?: string;
+    readonly hitCondition?: string;
+    readonly logMessage?: string;
+    readonly location?: Location;
+    readonly functionName?: string;
+}
diff --git a/packages/plugin-ext/src/api/plugin-api.ts b/packages/plugin-ext/src/api/plugin-api.ts
index 13d2c0b27153e..9836bee0b4153 100644
--- a/packages/plugin-ext/src/api/plugin-api.ts
+++ b/packages/plugin-ext/src/api/plugin-api.ts
@@ -46,14 +46,18 @@ import {
     TextEdit,
     DocumentSymbol,
     ReferenceContext,
-    Location,
     FileWatcherSubscriberOptions,
     FileChangeEvent,
     TextDocumentShowOptions,
-    WorkspaceRootsChangeEvent
+    WorkspaceRootsChangeEvent,
+    Location,
+    Breakpoint
 } from './model';
 import { ExtPluginApi } from '../common/plugin-ext-api-contribution';
 import { CancellationToken, Progress, ProgressOptions } from '@theia/plugin';
+import { IJSONSchema, IJSONSchemaSnippet } from '@theia/core/lib/common/json-schema';
+import { DebuggerDescription } from '@theia/debug/lib/common/debug-service';
+import { DebugProtocol } from 'vscode-debugprotocol';
 
 export interface PluginInitData {
     plugins: PluginMetadata[];
@@ -156,15 +160,17 @@ export interface TerminalServiceExt {
 }
 
 export interface ConnectionMain {
+    $createConnection(id: string): Promise<void>;
+    $deleteConnection(id: string): Promise<void>;
     $sendMessage(id: string, message: string): void;
     $createConnection(id: string): Promise<void>;
     $deleteConnection(id: string): Promise<void>;
 }
 
 export interface ConnectionExt {
-    $sendMessage(id: string, message: string): void;
     $createConnection(id: string): Promise<void>;
     $deleteConnection(id: string): Promise<void>
+    $sendMessage(id: string, message: string): void;
 }
 
 export interface TerminalServiceMain {
@@ -903,6 +909,32 @@ export interface WebviewsMain {
     $unregisterSerializer(viewType: string): void;
 }
 
+export interface DebugExt {
+    $onSessionCustomEvent(sessionId: string, event: string, body?: any): void;
+    $breakpointsDidChange(all: Breakpoint[], added: Breakpoint[], removed: Breakpoint[], changed: Breakpoint[]): void;
+    $sessionDidCreate(sessionId: string): void;
+    $sessionDidDestroy(sessionId: string): void;
+    $sessionDidChange(sessionId: string | undefined): void;
+    $provideDebugConfigurations(contributionId: string, folder: string | undefined): Promise<theia.DebugConfiguration[]>;
+    $resolveDebugConfigurations(contributionId: string, debugConfiguration: theia.DebugConfiguration, folder: string | undefined): Promise<theia.DebugConfiguration | undefined>;
+    $getSupportedLanguages(contributionId: string): Promise<string[]>;
+    $getSchemaAttributes(contributionId: string): Promise<IJSONSchema[]>;
+    $getConfigurationSnippets(contributionId: string): Promise<IJSONSchemaSnippet[]>;
+    $createDebugSession(contributionId: string, debugConfiguration: theia.DebugConfiguration): Promise<string>;
+    $terminateDebugSession(sessionId: string): Promise<void>;
+}
+
+export interface DebugMain {
+    $appendToDebugConsole(value: string): Promise<void>;
+    $appendLineToDebugConsole(value: string): Promise<void>;
+    $registerDebugConfigurationProvider(contributorId: string, description: DebuggerDescription): Promise<void>;
+    $unregisterDebugConfigurationProvider(contributorId: string): Promise<void>;
+    $addBreakpoints(breakpoints: Breakpoint[]): Promise<void>;
+    $removeBreakpoints(breakpoints: Breakpoint[]): Promise<void>;
+    $startDebugging(folder: theia.WorkspaceFolder | undefined, nameOrConfiguration: string | theia.DebugConfiguration): Promise<boolean>;
+    $customRequest(command: string, args?: any): Promise<DebugProtocol.Response>;
+}
+
 export const PLUGIN_RPC_CONTEXT = {
     COMMAND_REGISTRY_MAIN: <ProxyIdentifier<CommandRegistryMain>>createProxyIdentifier<CommandRegistryMain>('CommandRegistryMain'),
     QUICK_OPEN_MAIN: createProxyIdentifier<QuickOpenMain>('QuickOpenMain'),
@@ -923,6 +955,7 @@ export const PLUGIN_RPC_CONTEXT = {
     WEBVIEWS_MAIN: createProxyIdentifier<WebviewsMain>('WebviewsMain'),
     TASKS_MAIN: createProxyIdentifier<TasksMain>('TasksMain'),
     LANGUAGES_CONTRIBUTION_MAIN: createProxyIdentifier<LanguagesContributionMain>('LanguagesContributionMain'),
+    DEBUG_MAIN: createProxyIdentifier<DebugMain>('DebugMain')
 };
 
 export const MAIN_RPC_CONTEXT = {
@@ -943,6 +976,7 @@ export const MAIN_RPC_CONTEXT = {
     WEBVIEWS_EXT: createProxyIdentifier<WebviewsExt>('WebviewsExt'),
     TASKS_EXT: createProxyIdentifier<TasksExt>('TasksExt'),
     LANGUAGES_CONTRIBUTION_EXT: createProxyIdentifier<LanguagesContributionExt>('LanguagesContributionExt'),
+    DEBUG_EXT: createProxyIdentifier<DebugExt>('DebugExt')
 };
 
 export interface TasksExt {
diff --git a/packages/plugin-ext/src/common/connection.ts b/packages/plugin-ext/src/common/connection.ts
index 2d878207812b6..b806b74988186 100644
--- a/packages/plugin-ext/src/common/connection.ts
+++ b/packages/plugin-ext/src/common/connection.ts
@@ -17,6 +17,7 @@ import { Disposable } from './disposable-util';
 import { PluginMessageReader } from './plugin-message-reader';
 import { PluginMessageWriter } from './plugin-message-writer';
 import { MessageReader, MessageWriter, Message } from 'vscode-jsonrpc';
+import { IWebSocket } from 'vscode-ws-jsonrpc/lib/socket/socket';
 
 /**
  * The interface for describing the connection between plugins and main side.
@@ -37,16 +38,10 @@ export interface Connection extends Disposable {
  * The container for message reader and writer which can be used to create connection between plugins and main side.
  */
 export class PluginConnection implements Connection {
-    reader: PluginMessageReader;
-    writer: PluginMessageWriter;
-    clearConnection: () => void;
-
-    constructor(protected readonly pluginMessageReader: PluginMessageReader,
-        protected readonly pluginMessageWriter: PluginMessageWriter,
-        dispose: () => void) {
-        this.reader = pluginMessageReader;
-        this.writer = pluginMessageWriter;
-        this.clearConnection = dispose;
+    constructor(
+        readonly reader: PluginMessageReader,
+        readonly writer: PluginMessageWriter,
+        readonly dispose: () => void) {
     }
 
     forward(to: Connection, map: (message: Message) => Message = message => message): void {
@@ -55,11 +50,33 @@ export class PluginConnection implements Connection {
             to.writer.write(output);
         });
     }
+}
+
+/**
+ * [IWebSocket](#IWebSocket) implementation over RPC.
+ */
+export class PluginWebSocketChannel implements IWebSocket {
+    constructor(protected readonly connection: PluginConnection) { }
+
+    send(content: string): void {
+        this.connection.writer.write(content);
+    }
+
+    // tslint:disable-next-line:no-any
+    onMessage(cb: (data: any) => void): void {
+        this.connection.reader.listen(cb);
+    }
+
+    // tslint:disable-next-line:no-any
+    onError(cb: (reason: any) => void): void {
+        this.connection.reader.onError(e => cb(e));
+    }
+
+    onClose(cb: (code: number, reason: string) => void): void {
+        this.connection.reader.onClose(() => cb(-1, 'closed'));
+    }
 
-    /**
-     * Has to be called when the connection was closed.
-     */
     dispose(): void {
-        this.clearConnection();
+        this.connection.dispose();
     }
 }
diff --git a/packages/plugin-ext/src/common/plugin-message-writer.ts b/packages/plugin-ext/src/common/plugin-message-writer.ts
index 47b25631291ae..8394d0ea8aa75 100644
--- a/packages/plugin-ext/src/common/plugin-message-writer.ts
+++ b/packages/plugin-ext/src/common/plugin-message-writer.ts
@@ -14,20 +14,24 @@
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
 
-import { AbstractMessageWriter } from 'vscode-jsonrpc/lib/messageWriter';
+import { AbstractMessageWriter, MessageWriter } from 'vscode-jsonrpc/lib/messageWriter';
 import { ConnectionMain, ConnectionExt } from '../api/plugin-api';
 import { Message } from 'vscode-jsonrpc';
 
 /**
  * Support for writing string message through RPC protocol.
  */
-export class PluginMessageWriter extends AbstractMessageWriter {
-    constructor(protected readonly id: string, protected readonly proxy: ConnectionMain | ConnectionExt) {
+export class PluginMessageWriter extends AbstractMessageWriter implements MessageWriter {
+    constructor(
+        protected readonly id: string,
+        protected readonly proxy: ConnectionMain | ConnectionExt) {
         super();
     }
 
-    write(message: Message): void {
-        const content = JSON.stringify(message);
+    write(message: string): void;
+    write(message: Message): void;
+    write(arg: string | Message): void {
+        const content = JSON.stringify(arg);
         this.proxy.$sendMessage(this.id, content);
     }
 }
diff --git a/packages/plugin-ext/src/common/plugin-protocol.ts b/packages/plugin-ext/src/common/plugin-protocol.ts
index 9209aeacebedc..5fc1d3b4e2eef 100644
--- a/packages/plugin-ext/src/common/plugin-protocol.ts
+++ b/packages/plugin-ext/src/common/plugin-protocol.ts
@@ -20,6 +20,7 @@ import { LogPart } from './types';
 import { CharacterPair, CommentRule, PluginAPIFactory, Plugin } from '../api/plugin-api';
 import { PreferenceSchema } from '@theia/core/lib/browser/preferences';
 import { ExtPluginApi } from './plugin-ext-api-contribution';
+import { IJSONSchema, IJSONSchemaSnippet } from '@theia/core/lib/common/json-schema';
 
 export const hostedServicePath = '/services/hostedPlugin';
 
@@ -60,6 +61,7 @@ export interface PluginPackageContribution {
     views?: { [location: string]: PluginPackageView[] };
     menus?: { [location: string]: PluginPackageMenu[] };
     keybindings?: PluginPackageKeybinding[];
+    debuggers?: PluginPackageDebuggersContribution[];
 }
 
 export interface PluginPackageViewContainer {
@@ -98,6 +100,32 @@ export interface ScopeMap {
     [scopeName: string]: string;
 }
 
+export interface PlatformSpecificAdapterContribution {
+    program?: string;
+    args?: string[];
+    runtime?: string;
+    runtimeArgs?: string[];
+}
+
+/**
+ * This interface describes a package.json debuggers contribution section object.
+ */
+export interface PluginPackageDebuggersContribution extends PlatformSpecificAdapterContribution {
+    type: string;
+    label?: string;
+    languages?: string[];
+    enableBreakpointsFor?: { languageIds: string[] };
+    configurationAttributes: { [request: string]: IJSONSchema };
+    configurationSnippets: IJSONSchemaSnippet[];
+    variables?: ScopeMap;
+    adapterExecutableCommand?: string;
+    win?: PlatformSpecificAdapterContribution;
+    winx86?: PlatformSpecificAdapterContribution;
+    windows?: PlatformSpecificAdapterContribution;
+    osx?: PlatformSpecificAdapterContribution;
+    linux?: PlatformSpecificAdapterContribution;
+}
+
 /**
  * This interface describes a package.json languages contribution section object.
  */
@@ -311,6 +339,7 @@ export interface PluginContribution {
     views?: { [location: string]: View[] };
     menus?: { [location: string]: Menu[] };
     keybindings?: Keybinding[];
+    debuggers?: DebuggerContribution[];
 }
 
 export interface GrammarsContribution {
@@ -347,6 +376,27 @@ export interface LanguageConfiguration {
     wordPattern?: string;
 }
 
+/**
+ * This interface describes a package.json debuggers contribution section object.
+ */
+export interface DebuggerContribution extends PlatformSpecificAdapterContribution {
+    type: string,
+    label?: string,
+    languages?: string[],
+    enableBreakpointsFor?: {
+        languageIds: string[]
+    },
+    configurationAttributes?: IJSONSchema[],
+    configurationSnippets?: IJSONSchemaSnippet[],
+    variables?: ScopeMap,
+    adapterExecutableCommand?: string
+    win?: PlatformSpecificAdapterContribution;
+    winx86?: PlatformSpecificAdapterContribution;
+    windows?: PlatformSpecificAdapterContribution;
+    osx?: PlatformSpecificAdapterContribution;
+    linux?: PlatformSpecificAdapterContribution;
+}
+
 export interface IndentationRules {
     increaseIndentPattern: string;
     decreaseIndentPattern: string;
diff --git a/packages/plugin-ext/src/hosted/browser/worker/debug-stub.ts b/packages/plugin-ext/src/hosted/browser/worker/debug-stub.ts
new file mode 100644
index 0000000000000..8f8e44b884d11
--- /dev/null
+++ b/packages/plugin-ext/src/hosted/browser/worker/debug-stub.ts
@@ -0,0 +1,35 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { DebugExtImpl } from '../../../plugin/node/debug/debug';
+
+export function createDebugExtStub(): DebugExtImpl {
+    const err = new Error('Debug API works only in plugin container');
+
+    return new Proxy({}, {
+        get: function (obj, prop) {
+            throw err;
+        },
+
+        set(obj, prop, value) {
+            throw err;
+        },
+
+        apply: function (target, that, args) {
+            throw err;
+        }
+    }) as DebugExtImpl;
+}
diff --git a/packages/plugin-ext/src/hosted/browser/worker/worker-main.ts b/packages/plugin-ext/src/hosted/browser/worker/worker-main.ts
index d45efbc9b8aae..e2fc74302246a 100644
--- a/packages/plugin-ext/src/hosted/browser/worker/worker-main.ts
+++ b/packages/plugin-ext/src/hosted/browser/worker/worker-main.ts
@@ -24,7 +24,7 @@ import * as theia from '@theia/plugin';
 import { EnvExtImpl } from '../../../plugin/env';
 import { PreferenceRegistryExtImpl } from '../../../plugin/preference-registry';
 import { ExtPluginApi } from '../../../common/plugin-ext-api-contribution';
-import { ConnectionExtImpl } from '../../../plugin/connection-ext';
+import { createDebugExtStub } from './debug-stub';
 
 // tslint:disable-next-line:no-any
 const ctx = self as any;
@@ -47,8 +47,8 @@ function initialize(contextPath: string, pluginMetadata: PluginMetadata): void {
     ctx.importScripts('/context/' + contextPath);
 }
 const envExt = new EnvExtImpl(rpc);
-const connectionExt = new ConnectionExtImpl(rpc);
 const preferenceRegistryExt = new PreferenceRegistryExtImpl(rpc);
+const debugExt = createDebugExtStub();
 
 const pluginManager = new PluginManagerExtImpl({
     // tslint:disable-next-line:no-any
@@ -119,10 +119,11 @@ const pluginManager = new PluginManagerExtImpl({
     }
 }, envExt, preferenceRegistryExt);
 
-const apiFactory = createAPIFactory(rpc,
+const apiFactory = createAPIFactory(
+    rpc,
     pluginManager,
     envExt,
-    connectionExt,
+    debugExt,
     preferenceRegistryExt);
 let defaultApi: typeof theia;
 
diff --git a/packages/plugin-ext/src/hosted/node/plugin-host-rpc.ts b/packages/plugin-ext/src/hosted/node/plugin-host-rpc.ts
index 3481c59598d24..1fa8993631e2a 100644
--- a/packages/plugin-ext/src/hosted/node/plugin-host-rpc.ts
+++ b/packages/plugin-ext/src/hosted/node/plugin-host-rpc.ts
@@ -21,7 +21,7 @@ import { createAPIFactory } from '../../plugin/plugin-context';
 import { EnvExtImpl } from '../../plugin/env';
 import { PreferenceRegistryExtImpl } from '../../plugin/preference-registry';
 import { ExtPluginApi } from '../../common/plugin-ext-api-contribution';
-import { ConnectionExtImpl } from '../../plugin/connection-ext';
+import { DebugExtImpl } from '../../plugin/node/debug/debug';
 
 /**
  * Handle the RPC calls.
@@ -38,15 +38,17 @@ export class PluginHostRPC {
 
     initialize() {
         const envExt = new EnvExtImpl(this.rpc);
-        const connectionExt = new ConnectionExtImpl(this.rpc);
+        const debugExt = new DebugExtImpl(this.rpc);
         const preferenceRegistryExt = new PreferenceRegistryExtImpl(this.rpc);
         this.pluginManager = this.createPluginManager(envExt, preferenceRegistryExt, this.rpc);
         this.rpc.set(MAIN_RPC_CONTEXT.HOSTED_PLUGIN_MANAGER_EXT, this.pluginManager);
         this.rpc.set(MAIN_RPC_CONTEXT.PREFERENCE_REGISTRY_EXT, preferenceRegistryExt);
-        PluginHostRPC.apiFactory = createAPIFactory(this.rpc,
+
+        PluginHostRPC.apiFactory = createAPIFactory(
+            this.rpc,
             this.pluginManager,
             envExt,
-            connectionExt,
+            debugExt,
             preferenceRegistryExt);
     }
 
diff --git a/packages/plugin-ext/src/hosted/node/plugin-reader.ts b/packages/plugin-ext/src/hosted/node/plugin-reader.ts
index 1cbe426ab3e0e..9dc623f6662bd 100644
--- a/packages/plugin-ext/src/hosted/node/plugin-reader.ts
+++ b/packages/plugin-ext/src/hosted/node/plugin-reader.ts
@@ -75,7 +75,10 @@ export class HostedPluginReader implements BackendApplicationContribution {
             return undefined;
         }
 
-        const plugin: PluginPackage = require(packageJsonPath);
+        let rawData = fs.readFileSync(packageJsonPath).toString();
+        rawData = this.localize(rawData, path);
+
+        const plugin: PluginPackage = JSON.parse(rawData);
         plugin.packagePath = path;
         const pluginMetadata = this.scanner.getPluginMetadata(plugin);
         if (pluginMetadata.model.entryPoint.backend) {
@@ -95,6 +98,21 @@ export class HostedPluginReader implements BackendApplicationContribution {
         return pluginMetadata;
     }
 
+    private localize(rawData: string, pluginPath: string): string {
+        const nlsPath = pluginPath + 'package.nls.json';
+        if (fs.existsSync(nlsPath)) {
+            const nlsMap: {
+                [key: string]: string
+            } = require(nlsPath);
+            for (const key of Object.keys(nlsMap)) {
+                const value = nlsMap[key].replace(/\"/g, '\\"');
+                rawData = rawData.split('%' + key + '%').join(value);
+            }
+        }
+
+        return rawData;
+    }
+
     getPlugin(): PluginMetadata | undefined {
         return this.plugin;
     }
diff --git a/packages/plugin-ext/src/hosted/node/scanners/scanner-theia.ts b/packages/plugin-ext/src/hosted/node/scanners/scanner-theia.ts
index 8c43a1722aacc..e4593709adafb 100644
--- a/packages/plugin-ext/src/hosted/node/scanners/scanner-theia.ts
+++ b/packages/plugin-ext/src/hosted/node/scanners/scanner-theia.ts
@@ -36,7 +36,9 @@ import {
     View,
     PluginPackageView,
     Menu,
-    PluginPackageMenu
+    PluginPackageMenu,
+    PluginPackageDebuggersContribution,
+    DebuggerContribution
 } from '../../../common/plugin-protocol';
 import * as fs from 'fs';
 import * as path from 'path';
@@ -44,6 +46,20 @@ import { isObject } from 'util';
 import { GrammarsReader } from './grammars-reader';
 import { CharacterPair } from '../../../api/plugin-api';
 import * as jsoncparser from 'jsonc-parser';
+import { IJSONSchema } from '@theia/core/lib/common/json-schema';
+import { deepClone } from '@theia/core/lib/common/objects';
+
+namespace nls {
+    export function localize(key: string, _default: string) {
+        return _default;
+    }
+}
+
+const INTERNAL_CONSOLE_OPTIONS_SCHEMA = {
+    enum: ['neverOpen', 'openOnSessionStart', 'openOnFirstSessionStart'],
+    default: 'openOnFirstSessionStart',
+    description: nls.localize('internalConsoleOptions', 'Controls when the internal debug console should open.')
+};
 
 @injectable()
 export class TheiaPluginScanner implements PluginScanner {
@@ -146,6 +162,12 @@ export class TheiaPluginScanner implements PluginScanner {
         if (rawPlugin.contributes && rawPlugin.contributes.keybindings) {
             contributions.keybindings = rawPlugin.contributes.keybindings.map(rawKeybinding => this.readKeybinding(rawKeybinding));
         }
+
+        if (rawPlugin.contributes!.debuggers) {
+            const debuggers = this.readDebuggers(rawPlugin.contributes.debuggers!);
+            contributions.debuggers = debuggers;
+        }
+
         return contributions;
     }
 
@@ -243,6 +265,115 @@ export class TheiaPluginScanner implements PluginScanner {
 
     }
 
+    private readDebuggers(rawDebuggers: PluginPackageDebuggersContribution[]): DebuggerContribution[] {
+        return rawDebuggers.map(rawDebug => this.readDebugger(rawDebug));
+    }
+
+    private readDebugger(rawDebugger: PluginPackageDebuggersContribution): DebuggerContribution {
+        const result: DebuggerContribution = {
+            type: rawDebugger.type,
+            label: rawDebugger.label,
+            languages: rawDebugger.languages,
+            enableBreakpointsFor: rawDebugger.enableBreakpointsFor,
+            variables: rawDebugger.variables,
+            adapterExecutableCommand: rawDebugger.adapterExecutableCommand,
+            configurationSnippets: rawDebugger.configurationSnippets,
+            win: rawDebugger.win,
+            winx86: rawDebugger.winx86,
+            windows: rawDebugger.windows,
+            osx: rawDebugger.osx,
+            linux: rawDebugger.linux,
+            program: rawDebugger.program,
+            args: rawDebugger.args,
+            runtime: rawDebugger.runtime,
+            runtimeArgs: rawDebugger.runtimeArgs
+        };
+
+        result.configurationAttributes = rawDebugger.configurationAttributes
+            && this.resolveSchemaAttributes(rawDebugger.type, rawDebugger.configurationAttributes);
+
+        return result;
+    }
+
+    protected resolveSchemaAttributes(type: string, configurationAttributes: { [request: string]: IJSONSchema }): IJSONSchema[] {
+        const taskSchema = {};
+        return Object.keys(configurationAttributes).map(request => {
+            const attributes: IJSONSchema = deepClone(configurationAttributes[request]);
+            const defaultRequired = ['name', 'type', 'request'];
+            attributes.required = attributes.required && attributes.required.length ? defaultRequired.concat(attributes.required) : defaultRequired;
+            attributes.additionalProperties = false;
+            attributes.type = 'object';
+            if (!attributes.properties) {
+                attributes.properties = {};
+            }
+            const properties = attributes.properties;
+            properties['type'] = {
+                enum: [type],
+                description: nls.localize('debugType', 'Type of configuration.'),
+                pattern: '^(?!node2)',
+                errorMessage: nls.localize('debugTypeNotRecognised',
+                    'The debug type is not recognized. Make sure that you have a corresponding debug extension installed and that it is enabled.'),
+                patternErrorMessage: nls.localize('node2NotSupported',
+                    '"node2" is no longer supported, use "node" instead and set the "protocol" attribute to "inspector".')
+            };
+            properties['name'] = {
+                type: 'string',
+                description: nls.localize('debugName', 'Name of configuration; appears in the launch configuration drop down menu.'),
+                default: 'Launch'
+            };
+            properties['request'] = {
+                enum: [request],
+                description: nls.localize('debugRequest', 'Request type of configuration. Can be "launch" or "attach".'),
+            };
+            properties['debugServer'] = {
+                type: 'number',
+                description: nls.localize('debugServer',
+                    'For debug extension development only: if a port is specified VS Code tries to connect to a debug adapter running in server mode'),
+                default: 4711
+            };
+            properties['preLaunchTask'] = {
+                anyOf: [taskSchema, {
+                    type: ['string', 'null'],
+                }],
+                default: '',
+                description: nls.localize('debugPrelaunchTask', 'Task to run before debug session starts.')
+            };
+            properties['postDebugTask'] = {
+                anyOf: [taskSchema, {
+                    type: ['string', 'null'],
+                }],
+                default: '',
+                description: nls.localize('debugPostDebugTask', 'Task to run after debug session ends.')
+            };
+            properties['internalConsoleOptions'] = INTERNAL_CONSOLE_OPTIONS_SCHEMA;
+
+            const osProperties = Object.assign({}, properties);
+            properties['windows'] = {
+                type: 'object',
+                description: nls.localize('debugWindowsConfiguration', 'Windows specific launch configuration attributes.'),
+                properties: osProperties
+            };
+            properties['osx'] = {
+                type: 'object',
+                description: nls.localize('debugOSXConfiguration', 'OS X specific launch configuration attributes.'),
+                properties: osProperties
+            };
+            properties['linux'] = {
+                type: 'object',
+                description: nls.localize('debugLinuxConfiguration', 'Linux specific launch configuration attributes.'),
+                properties: osProperties
+            };
+            Object.keys(attributes.properties).forEach(name => {
+                // Use schema allOf property to get independent error reporting #21113
+                attributes!.properties![name].pattern = attributes!.properties![name].pattern || '^(?!.*\\$\\{(env|config|command)\\.)';
+                attributes!.properties![name].patternErrorMessage = attributes!.properties![name].patternErrorMessage ||
+                    nls.localize('deprecatedVariables', "'env.', 'config.' and 'command.' are deprecated, use 'env:', 'config:' and 'command:' instead.");
+            });
+
+            return attributes;
+        });
+    }
+
     private extractValidAutoClosingPairs(langId: string, configuration: PluginPackageLanguageContributionConfiguration): AutoClosingPairConditional[] | undefined {
         const source = configuration.autoClosingPairs;
         if (typeof source === 'undefined') {
diff --git a/packages/plugin-ext/src/main/browser/connection-main.ts b/packages/plugin-ext/src/main/browser/connection-main.ts
index 640d21f63bcca..5dd543bfda4b5 100644
--- a/packages/plugin-ext/src/main/browser/connection-main.ts
+++ b/packages/plugin-ext/src/main/browser/connection-main.ts
@@ -25,6 +25,7 @@ import { PluginMessageWriter } from '../../common/plugin-message-writer';
  * Creates holds the connections to the plugins. Allows to send a message to the plugin by getting already created connection via id.
  */
 export class ConnectionMainImpl implements ConnectionMain {
+
     private proxy: ConnectionExt;
     private connections = new Map<string, PluginConnection>();
     constructor(rpc: RPCProtocol) {
diff --git a/packages/plugin-ext/src/main/browser/debug/debug-main.ts b/packages/plugin-ext/src/main/browser/debug/debug-main.ts
new file mode 100644
index 0000000000000..a998454980291
--- /dev/null
+++ b/packages/plugin-ext/src/main/browser/debug/debug-main.ts
@@ -0,0 +1,247 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+// tslint:disable:no-any
+
+import { interfaces } from 'inversify';
+import { RPCProtocol } from '../../../api/rpc-protocol';
+import {
+    DebugMain,
+    DebugExt,
+    MAIN_RPC_CONTEXT
+} from '../../../api/plugin-api';
+import { DebugSessionManager } from '@theia/debug/lib/browser/debug-session-manager';
+import { Breakpoint, WorkspaceFolder } from '../../../api/model';
+import { LabelProvider } from '@theia/core/lib/browser';
+import { EditorManager } from '@theia/editor/lib/browser';
+import { BreakpointManager } from '@theia/debug/lib/browser/breakpoint/breakpoint-manager';
+import { DebugBreakpoint } from '@theia/debug/lib/browser/model/debug-breakpoint';
+import URI from 'vscode-uri';
+import { DebugConsoleSession } from '@theia/debug/lib/browser/console/debug-console-session';
+import { SourceBreakpoint } from '@theia/debug/lib/browser/breakpoint/breakpoint-marker';
+import { DebugConfiguration } from '@theia/debug/lib/common/debug-configuration';
+import { ConnectionMainImpl } from '../connection-main';
+import { DebuggerDescription } from '@theia/debug/lib/common/debug-service';
+import { DebugProtocol } from 'vscode-debugprotocol';
+import { DebugConfigurationManager } from '@theia/debug/lib/browser/debug-configuration-manager';
+import { TerminalService } from '@theia/terminal/lib/browser/base/terminal-service';
+import { MessageClient } from '@theia/core/lib/common/message-service-protocol';
+import { OutputChannelManager } from '@theia/output/lib/common/output-channel';
+import { DebugPreferences } from '@theia/debug/lib/browser/debug-preferences';
+import { PluginDebugAdapterContribution } from './plugin-debug-adapter-contribution';
+import { PluginDebugSessionContributionRegistrator, PluginDebugSessionContributionRegistry } from './plugin-debug-session-contribution-registry';
+import { DisposableCollection } from '@theia/core/lib/common/disposable';
+import { PluginDebugSessionFactory } from './plugin-debug-session-factory';
+import { PluginWebSocketChannel } from '../../../common/connection';
+import { PluginDebugAdapterContributionRegistrator, PluginDebugService } from './plugin-debug-service';
+import { DebugSchemaUpdater } from '@theia/debug/lib/browser/debug-schema-updater';
+
+export class DebugMainImpl implements DebugMain {
+    private readonly debugExt: DebugExt;
+
+    private readonly sessionManager: DebugSessionManager;
+    private readonly labelProvider: LabelProvider;
+    private readonly editorManager: EditorManager;
+    private readonly breakpointsManager: BreakpointManager;
+    private readonly debugConsoleSession: DebugConsoleSession;
+    private readonly configurationManager: DebugConfigurationManager;
+    private readonly terminalService: TerminalService;
+    private readonly messages: MessageClient;
+    private readonly outputChannelManager: OutputChannelManager;
+    private readonly debugPreferences: DebugPreferences;
+    private readonly sessionContributionRegistrator: PluginDebugSessionContributionRegistrator;
+    private readonly adapterContributionRegistrator: PluginDebugAdapterContributionRegistrator;
+    private readonly debugSchemaUpdater: DebugSchemaUpdater;
+
+    // registered plugins per contributorId
+    private readonly toDispose = new Map<string, DisposableCollection>();
+
+    constructor(rpc: RPCProtocol, readonly connectionMain: ConnectionMainImpl, container: interfaces.Container) {
+        this.debugExt = rpc.getProxy(MAIN_RPC_CONTEXT.DEBUG_EXT);
+        this.sessionManager = container.get(DebugSessionManager);
+        this.labelProvider = container.get(LabelProvider);
+        this.editorManager = container.get(EditorManager);
+        this.breakpointsManager = container.get(BreakpointManager);
+        this.debugConsoleSession = container.get(DebugConsoleSession);
+        this.configurationManager = container.get(DebugConfigurationManager);
+        this.terminalService = container.get(TerminalService);
+        this.messages = container.get(MessageClient);
+        this.outputChannelManager = container.get(OutputChannelManager);
+        this.debugPreferences = container.get(DebugPreferences);
+        this.adapterContributionRegistrator = container.get(PluginDebugService);
+        this.sessionContributionRegistrator = container.get(PluginDebugSessionContributionRegistry);
+        this.debugSchemaUpdater = container.get(DebugSchemaUpdater);
+
+        // TODO: distinguish added/deleted breakpoints
+        this.breakpointsManager.onDidChangeMarkers(uri => {
+            const all = this.breakpointsManager.getBreakpoints();
+            const affected = this.breakpointsManager.getBreakpoints(uri);
+            this.debugExt.$breakpointsDidChange(this.toTheiaPluginApiBreakpoints(all), [], [], this.toTheiaPluginApiBreakpoints(affected));
+        });
+
+        this.sessionManager.onDidCreateDebugSession(debugSession => this.debugExt.$sessionDidCreate(debugSession.id));
+        this.sessionManager.onDidDestroyDebugSession(debugSession => this.debugExt.$sessionDidDestroy(debugSession.id));
+        this.sessionManager.onDidChangeActiveDebugSession(event => this.debugExt.$sessionDidChange(event.current && event.current.id));
+        this.sessionManager.onDidReceiveDebugSessionCustomEvent(event => this.debugExt.$onSessionCustomEvent(event.session.id, event.event, event.body));
+    }
+
+    async $appendToDebugConsole(value: string): Promise<void> {
+        this.debugConsoleSession.append(value);
+    }
+
+    async $appendLineToDebugConsole(value: string): Promise<void> {
+        this.debugConsoleSession.appendLine(value);
+    }
+
+    async $registerDebugConfigurationProvider(contributorId: string, description: DebuggerDescription): Promise<void> {
+        const disposable = new DisposableCollection();
+        this.toDispose.set(contributorId, disposable);
+
+        const debugAdapterContributor = new PluginDebugAdapterContribution(
+            description.type,
+            description.label,
+            this.debugExt.$getSupportedLanguages(contributorId),
+            contributorId,
+            this.debugExt);
+
+        const debugSessionFactory = new PluginDebugSessionFactory(
+            this.terminalService,
+            this.editorManager,
+            this.breakpointsManager,
+            this.labelProvider,
+            this.messages,
+            this.outputChannelManager,
+            this.debugPreferences,
+            async (sessionId: string) => {
+                const connection = await this.connectionMain.ensureConnection(sessionId);
+                return new PluginWebSocketChannel(connection);
+            }
+        );
+
+        disposable.push(this.adapterContributionRegistrator.registerDebugAdapterContribution(debugAdapterContributor));
+        disposable.push(
+            this.sessionContributionRegistrator.registerDebugSessionContribution(
+                {
+                    debugType: description.type,
+                    debugSessionFactory: () => debugSessionFactory
+                })
+        );
+
+        this.debugSchemaUpdater.update();
+    }
+
+    async $unregisterDebugConfigurationProvider(contributorId: string): Promise<void> {
+        const disposable = this.toDispose.get(contributorId);
+        if (disposable) {
+            disposable.dispose();
+            this.toDispose.delete(contributorId);
+            this.debugSchemaUpdater.update();
+        }
+    }
+
+    async $addBreakpoints(breakpoints: Breakpoint[]): Promise<void> {
+        this.sessionManager.addBreakpoints(this.toInternalBreakpoints(breakpoints));
+    }
+
+    async $removeBreakpoints(breakpoints: Breakpoint[]): Promise<void> {
+        this.sessionManager.deleteBreakpoints(this.toInternalBreakpoints(breakpoints));
+    }
+
+    async $customRequest(sessionId: string, command: string, args?: any): Promise<DebugProtocol.Response> {
+        const session = this.sessionManager.getSession(sessionId);
+        if (session) {
+            return session.sendCustomRequest(command, args);
+        }
+
+        throw new Error(`Debug session '${sessionId}' not found`);
+    }
+
+    async $startDebugging(folder: WorkspaceFolder | undefined, nameOrConfiguration: string | DebugConfiguration): Promise<boolean> {
+        let configuration: DebugConfiguration | undefined;
+
+        if (typeof nameOrConfiguration === 'string') {
+            for (const options of this.configurationManager.all) {
+                if (options.configuration.name === nameOrConfiguration) {
+                    configuration = options.configuration;
+                }
+            }
+        } else {
+            configuration = nameOrConfiguration;
+        }
+
+        if (!configuration) {
+            console.error(`There is no debug configuration for ${nameOrConfiguration}`);
+            return false;
+        }
+
+        const session = await this.sessionManager.start({
+            configuration,
+            workspaceFolderUri: folder && URI.revive(folder.uri).toString()
+        });
+
+        return !!session;
+    }
+
+    private toInternalBreakpoints(breakpoints: Breakpoint[]): DebugBreakpoint[] {
+        return breakpoints
+            .filter(breakpoint => !!breakpoint.location)
+            .map(breakpoint => {
+                const location = breakpoint.location!;
+                const uri = URI.revive(location.uri);
+                const uriString = uri.toString();
+
+                const origin = {
+                    uri: uriString,
+                    enabled: true,
+                    raw: {
+                        line: location.range.startLineNumber,
+                        column: location.range.startColumn,
+                        condition: breakpoint.condition,
+                        hitCondition: breakpoint.hitCondition,
+                        logMessage: breakpoint.logMessage
+                    }
+                };
+
+                return new DebugBreakpoint(origin,
+                    this.labelProvider,
+                    this.breakpointsManager,
+                    this.editorManager,
+                    this.sessionManager.currentSession);
+            });
+    }
+
+    private toTheiaPluginApiBreakpoints(sourceBreakpoints: SourceBreakpoint[]): Breakpoint[] {
+        return sourceBreakpoints.map(b => {
+            const breakpoint = {
+                enabled: b.enabled,
+                condition: b.raw.condition,
+                hitCondition: b.raw.hitCondition,
+                logMessage: b.raw.logMessage,
+                location: {
+                    uri: URI.parse(b.uri),
+                    range: {
+                        startLineNumber: b.raw.line,
+                        startColumn: b.raw.column || 0,
+                        endLineNumber: b.raw.line,
+                        endColumn: b.raw.column || 0
+                    }
+                }
+            };
+
+            return breakpoint;
+        });
+    }
+}
diff --git a/packages/plugin-ext/src/main/browser/debug/plugin-debug-adapter-contribution.ts b/packages/plugin-ext/src/main/browser/debug/plugin-debug-adapter-contribution.ts
new file mode 100644
index 0000000000000..1031a4547775e
--- /dev/null
+++ b/packages/plugin-ext/src/main/browser/debug/plugin-debug-adapter-contribution.ts
@@ -0,0 +1,58 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { DebugExt, } from '../../../api/plugin-api';
+import { DebugConfiguration } from '@theia/debug/lib/common/debug-configuration';
+import { IJSONSchemaSnippet, IJSONSchema } from '@theia/core/lib/common/json-schema';
+import { MaybePromise } from '@theia/core/lib/common/types';
+import { DebugAdapterContribution } from '@theia/debug/lib/common/debug-model';
+
+/**
+ * Plugin [DebugAdapterContribution](#DebugAdapterContribution) with functionality
+ * to create / terminated debug adapter session.
+ */
+export class PluginDebugAdapterContribution implements DebugAdapterContribution {
+    constructor(
+        readonly type: string,
+        readonly label: MaybePromise<string | undefined>,
+        readonly languages: MaybePromise<string[] | undefined>,
+        protected readonly contributorId: string,
+        protected readonly debugExt: DebugExt) { }
+
+    async provideDebugConfigurations(workspaceFolderUri: string | undefined): Promise<DebugConfiguration[]> {
+        return this.debugExt.$provideDebugConfigurations(this.contributorId, workspaceFolderUri);
+    }
+
+    async resolveDebugConfiguration(config: DebugConfiguration, workspaceFolderUri: string | undefined): Promise<DebugConfiguration | undefined> {
+        return this.debugExt.$resolveDebugConfigurations(this.contributorId, config, workspaceFolderUri);
+    }
+
+    async getSchemaAttributes(): Promise<IJSONSchema[]> {
+        return this.debugExt.$getSchemaAttributes(this.contributorId);
+    }
+
+    async getConfigurationSnippets(): Promise<IJSONSchemaSnippet[]> {
+        return this.debugExt.$getConfigurationSnippets(this.contributorId);
+    }
+
+    async createDebugSession(debugConfiguration: DebugConfiguration): Promise<string> {
+        return this.debugExt.$createDebugSession(this.contributorId, debugConfiguration);
+    }
+
+    async terminateDebugSession(sessionId: string): Promise<void> {
+        return this.debugExt.$terminateDebugSession(sessionId);
+    }
+}
diff --git a/packages/plugin-ext/src/main/browser/debug/plugin-debug-service.ts b/packages/plugin-ext/src/main/browser/debug/plugin-debug-service.ts
new file mode 100644
index 0000000000000..9c9740058964f
--- /dev/null
+++ b/packages/plugin-ext/src/main/browser/debug/plugin-debug-service.ts
@@ -0,0 +1,174 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { DebugService, DebuggerDescription, DebugPath } from '@theia/debug/lib/common/debug-service';
+import { Disposable, DisposableCollection } from '@theia/core/lib/common/disposable';
+import { DebugConfiguration } from '@theia/debug/lib/common/debug-configuration';
+import { IJSONSchema, IJSONSchemaSnippet } from '@theia/core/lib/common/json-schema';
+import { PluginDebugAdapterContribution } from './plugin-debug-adapter-contribution';
+import { injectable, inject, postConstruct } from 'inversify';
+import { WebSocketConnectionProvider } from '@theia/core/lib/browser/messaging/ws-connection-provider';
+
+/**
+ * Debug adapter contribution registrator.
+ */
+export interface PluginDebugAdapterContributionRegistrator {
+    /**
+     * Registers [PluginDebugAdapterContribution](#PluginDebugAdapterContribution).
+     * @param contrib contribution
+     */
+    registerDebugAdapterContribution(contrib: PluginDebugAdapterContribution): Disposable;
+
+    /**
+     * Unregisters [PluginDebugAdapterContribution](#PluginDebugAdapterContribution).
+     * @param debugType the debug type
+     */
+    unregisterDebugAdapterContribution(debugType: string): void;
+}
+
+/**
+ * Debug service to work with plugin and extension contributions.
+ */
+@injectable()
+export class PluginDebugService implements DebugService, PluginDebugAdapterContributionRegistrator {
+    protected readonly contributors = new Map<string, PluginDebugAdapterContribution>();
+    protected readonly toDispose = new DisposableCollection();
+
+    // maps session and contribution identifiers.
+    protected readonly sessionId2contrib = new Map<string, PluginDebugAdapterContribution>();
+    protected delegated: DebugService;
+
+    @inject(WebSocketConnectionProvider)
+    protected readonly connectionProvider: WebSocketConnectionProvider;
+
+    @postConstruct()
+    protected init(): void {
+        this.delegated = this.connectionProvider.createProxy<DebugService>(DebugPath);
+        this.toDispose.push(Disposable.create(() => this.delegated.dispose()));
+        this.toDispose.push(Disposable.create(() => {
+            for (const sessionId of this.sessionId2contrib.keys()) {
+                const contrib = this.sessionId2contrib.get(sessionId)!;
+                contrib.terminateDebugSession(sessionId);
+            }
+        }));
+    }
+
+    registerDebugAdapterContribution(contrib: PluginDebugAdapterContribution): Disposable {
+        const { type } = contrib;
+
+        if (this.contributors.has(type)) {
+            console.warn(`Debugger with type '${type}' already registered.`);
+            return Disposable.NULL;
+        }
+
+        this.contributors.set(type, contrib);
+        return Disposable.create(() => this.unregisterDebugAdapterContribution(type));
+    }
+
+    unregisterDebugAdapterContribution(debugType: string): void {
+        this.contributors.delete(debugType);
+    }
+
+    async debugTypes(): Promise<string[]> {
+        const debugTypes = await this.delegated.debugTypes();
+        return debugTypes.concat(Array.from(this.contributors.keys()));
+    }
+
+    async provideDebugConfigurations(debugType: string, workspaceFolderUri: string | undefined): Promise<DebugConfiguration[]> {
+        const contributor = this.contributors.get(debugType);
+        if (contributor) {
+            return contributor.provideDebugConfigurations && contributor.provideDebugConfigurations(workspaceFolderUri) || [];
+        } else {
+            return this.delegated.provideDebugConfigurations(debugType, workspaceFolderUri);
+        }
+    }
+
+    async resolveDebugConfiguration(config: DebugConfiguration, workspaceFolderUri: string | undefined): Promise<DebugConfiguration> {
+        let resolved = config;
+
+        for (const contributor of this.contributors.values()) {
+            if (contributor.resolveDebugConfiguration) {
+                try {
+                    resolved = await contributor.resolveDebugConfiguration(config, workspaceFolderUri) || resolved;
+                } catch (e) {
+                    console.error(e);
+                }
+            }
+        }
+
+        return this.delegated.resolveDebugConfiguration(resolved, workspaceFolderUri);
+    }
+
+    async getDebuggersForLanguage(language: string): Promise<DebuggerDescription[]> {
+        const debuggers = await this.delegated.getDebuggersForLanguage(language);
+
+        for (const contributor of this.contributors.values()) {
+            const languages = await contributor.languages;
+            if (languages && languages.indexOf(language) !== -1) {
+                const { type } = contributor;
+                debuggers.push({ type, label: await contributor.label || type });
+            }
+        }
+
+        return debuggers;
+    }
+
+    async getSchemaAttributes(debugType: string): Promise<IJSONSchema[]> {
+        const contributor = this.contributors.get(debugType);
+        if (contributor) {
+            return contributor.getSchemaAttributes && contributor.getSchemaAttributes() || [];
+        } else {
+            return this.delegated.getSchemaAttributes(debugType);
+        }
+    }
+
+    async getConfigurationSnippets(): Promise<IJSONSchemaSnippet[]> {
+        let snippets = await this.delegated.getConfigurationSnippets();
+
+        for (const contributor of this.contributors.values()) {
+            if (contributor.getConfigurationSnippets) {
+                snippets = snippets.concat(await contributor.getConfigurationSnippets());
+            }
+        }
+
+        return snippets;
+    }
+
+    async createDebugSession(config: DebugConfiguration): Promise<string> {
+        const contributor = this.contributors.get(config.type);
+        if (contributor) {
+            const sessionId = await contributor.createDebugSession(config);
+            this.sessionId2contrib.set(sessionId, contributor);
+            return sessionId;
+        } else {
+            return this.delegated.createDebugSession(config);
+        }
+    }
+
+    async terminateDebugSession(sessionId: string): Promise<void> {
+        const contributor = this.sessionId2contrib.get(sessionId);
+        if (contributor) {
+            this.sessionId2contrib.delete(sessionId);
+            return contributor.terminateDebugSession(sessionId);
+        } else {
+            return this.delegated.terminateDebugSession(sessionId);
+        }
+    }
+
+    dispose(): void {
+        this.toDispose.dispose();
+    }
+}
diff --git a/packages/plugin-ext/src/main/browser/debug/plugin-debug-session-contribution-registry.ts b/packages/plugin-ext/src/main/browser/debug/plugin-debug-session-contribution-registry.ts
new file mode 100644
index 0000000000000..b6d8dc7dd4819
--- /dev/null
+++ b/packages/plugin-ext/src/main/browser/debug/plugin-debug-session-contribution-registry.ts
@@ -0,0 +1,76 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { DebugSessionContributionRegistry, DebugSessionContribution } from '@theia/debug/lib/browser/debug-session-contribution';
+import { injectable, inject, named, postConstruct } from 'inversify';
+import { ContributionProvider } from '@theia/core/lib/common/contribution-provider';
+import { Disposable } from '@theia/core/lib/common/disposable';
+
+/**
+ * Debug session contribution registrator.
+ */
+export interface PluginDebugSessionContributionRegistrator {
+    /**
+     * Registers [DebugSessionContribution](#DebugSessionContribution).
+     * @param contrib contribution
+     */
+    registerDebugSessionContribution(contrib: DebugSessionContribution): Disposable;
+
+    /**
+     * Unregisters [DebugSessionContribution](#DebugSessionContribution).
+     * @param debugType the debug type
+     */
+    unregisterDebugSessionContribution(debugType: string): void;
+}
+
+/**
+ * Plugin debug session contribution registry implementation with functionality
+ * to register / unregister plugin contributions.
+ */
+@injectable()
+export class PluginDebugSessionContributionRegistry implements DebugSessionContributionRegistry, PluginDebugSessionContributionRegistrator {
+    protected readonly contribs = new Map<string, DebugSessionContribution>();
+
+    @inject(ContributionProvider) @named(DebugSessionContribution)
+    protected readonly contributions: ContributionProvider<DebugSessionContribution>;
+
+    @postConstruct()
+    protected init(): void {
+        for (const contrib of this.contributions.getContributions()) {
+            this.contribs.set(contrib.debugType, contrib);
+        }
+    }
+
+    get(debugType: string): DebugSessionContribution | undefined {
+        return this.contribs.get(debugType);
+    }
+
+    registerDebugSessionContribution(contrib: DebugSessionContribution): Disposable {
+        const { debugType } = contrib;
+
+        if (this.contribs.has(debugType)) {
+            console.warn(`Debug session contribution already registered for ${debugType}`);
+            return Disposable.NULL;
+        }
+
+        this.contribs.set(debugType, contrib);
+        return Disposable.create(() => this.unregisterDebugSessionContribution(debugType));
+    }
+
+    unregisterDebugSessionContribution(debugType: string): void {
+        this.contribs.delete(debugType);
+    }
+}
diff --git a/packages/plugin-ext/src/main/browser/debug/plugin-debug-session-factory.ts b/packages/plugin-ext/src/main/browser/debug/plugin-debug-session-factory.ts
new file mode 100644
index 0000000000000..310e824b6303a
--- /dev/null
+++ b/packages/plugin-ext/src/main/browser/debug/plugin-debug-session-factory.ts
@@ -0,0 +1,64 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { DefaultDebugSessionFactory, } from '@theia/debug/lib/browser/debug-session-contribution';
+import { TerminalService } from '@theia/terminal/lib/browser/base/terminal-service';
+import { EditorManager } from '@theia/editor/lib/browser/editor-manager';
+import { BreakpointManager } from '@theia/debug/lib/browser/breakpoint/breakpoint-manager';
+import { LabelProvider } from '@theia/core/lib/browser/label-provider';
+import { MessageClient } from '@theia/core/lib/common/message-service-protocol';
+import { OutputChannelManager } from '@theia/output/lib/common/output-channel';
+import { DebugPreferences } from '@theia/debug/lib/browser/debug-preferences';
+import { DebugSessionOptions } from '@theia/debug/lib/browser/debug-session-options';
+import { DebugSession } from '@theia/debug/lib/browser/debug-session';
+import { DebugSessionConnection } from '@theia/debug/lib/browser/debug-session-connection';
+import { IWebSocket } from 'vscode-ws-jsonrpc/lib/socket/socket';
+
+/**
+ * Session factory for a client debug session that communicates with debug adapter contributed as plugin.
+ * The main difference is to use a connection factory that creates [IWebSocket](#IWebSocket) over Rpc channel.
+ */
+export class PluginDebugSessionFactory extends DefaultDebugSessionFactory {
+    constructor(
+        protected readonly terminalService: TerminalService,
+        protected readonly editorManager: EditorManager,
+        protected readonly breakpoints: BreakpointManager,
+        protected readonly labelProvider: LabelProvider,
+        protected readonly messages: MessageClient,
+        protected readonly outputChannelManager: OutputChannelManager,
+        protected readonly debugPreferences: DebugPreferences,
+        protected readonly connectionFactory: (sessionId: string) => Promise<IWebSocket>
+    ) {
+        super();
+    }
+
+    get(sessionId: string, options: DebugSessionOptions): DebugSession {
+        const connection = new DebugSessionConnection(
+            sessionId,
+            this.connectionFactory,
+            this.getTraceOutputChannel());
+
+        return new DebugSession(
+            sessionId,
+            options,
+            connection,
+            this.terminalService,
+            this.editorManager,
+            this.breakpoints,
+            this.labelProvider,
+            this.messages);
+    }
+}
diff --git a/packages/plugin-ext/src/main/browser/keybindings/keybindings-contribution-handler.ts b/packages/plugin-ext/src/main/browser/keybindings/keybindings-contribution-handler.ts
index e812f35dae9b1..f51d8cda152ea 100644
--- a/packages/plugin-ext/src/main/browser/keybindings/keybindings-contribution-handler.ts
+++ b/packages/plugin-ext/src/main/browser/keybindings/keybindings-contribution-handler.ts
@@ -36,10 +36,13 @@ export class KeybindingsContributionPointHandler {
 
         const keybindings = contributions.keybindings;
         keybindings.forEach(keybinding => {
-            const keybindingResult = this.keybindingRegistry.getKeybindingsForKeySequence(KeySequence.parse(keybinding.keybinding));
-
-            this.handleShadingKeybindings(keybinding, keybindingResult.shadow);
-            this.handlePartialKeybindings(keybinding, keybindingResult.partial);
+            try {
+                const keybindingResult = this.keybindingRegistry.getKeybindingsForKeySequence(KeySequence.parse(keybinding.keybinding));
+                this.handleShadingKeybindings(keybinding, keybindingResult.shadow);
+                this.handlePartialKeybindings(keybinding, keybindingResult.partial);
+            } catch (e) {
+                this.logger.error(e.message || e);
+            }
         });
 
         this.keybindingRegistry.setKeymap(KeybindingScope.USER, keybindings);
diff --git a/packages/plugin-ext/src/main/browser/main-context.ts b/packages/plugin-ext/src/main/browser/main-context.ts
index 1151c1f963da9..95bcbc515aaec 100644
--- a/packages/plugin-ext/src/main/browser/main-context.ts
+++ b/packages/plugin-ext/src/main/browser/main-context.ts
@@ -35,6 +35,7 @@ import { ConnectionMainImpl } from './connection-main';
 import { WebviewsMainImpl } from './webviews-main';
 import { TasksMainImpl } from './tasks-main';
 import { LanguagesContributionMainImpl } from './languages-contribution-main';
+import { DebugMainImpl } from './debug/debug-main';
 
 export function setUpPluginApi(rpc: RPCProtocol, container: interfaces.Container): void {
     const commandRegistryMain = new CommandRegistryMainImpl(rpc, container);
@@ -92,4 +93,10 @@ export function setUpPluginApi(rpc: RPCProtocol, container: interfaces.Container
 
     const languagesContribution = new LanguagesContributionMainImpl(rpc, container, pluginConnection);
     rpc.set(PLUGIN_RPC_CONTEXT.LANGUAGES_CONTRIBUTION_MAIN, languagesContribution);
+
+    const connectionMain = new ConnectionMainImpl(rpc);
+    rpc.set(PLUGIN_RPC_CONTEXT.CONNECTION_MAIN, connectionMain);
+
+    const debugMain = new DebugMainImpl(rpc, connectionMain, container);
+    rpc.set(PLUGIN_RPC_CONTEXT.DEBUG_MAIN, debugMain);
 }
diff --git a/packages/plugin-ext/src/main/browser/plugin-ext-frontend-module.ts b/packages/plugin-ext/src/main/browser/plugin-ext-frontend-module.ts
index bad748343d972..4aa4d22121083 100644
--- a/packages/plugin-ext/src/main/browser/plugin-ext-frontend-module.ts
+++ b/packages/plugin-ext/src/main/browser/plugin-ext-frontend-module.ts
@@ -54,6 +54,10 @@ import { LanguageClientProviderImpl } from './language-provider/plugin-language-
 import { LanguageClientContributionProviderImpl } from './language-provider/language-client-contribution-provider-impl';
 import { LanguageClientContributionProvider } from './language-provider/language-client-contribution-provider';
 import { StoragePathService } from './storage-path-service';
+import { DebugSessionContributionRegistry } from '@theia/debug/lib/browser/debug-session-contribution';
+import { PluginDebugSessionContributionRegistry } from './debug/plugin-debug-session-contribution-registry';
+import { PluginDebugService } from './debug/plugin-debug-service';
+import { DebugService } from '@theia/debug/lib/common/debug-service';
 
 export default new ContainerModule((bind, unbind, isBound, rebind) => {
     bindHostedPluginPreferences(bind);
@@ -125,4 +129,10 @@ export default new ContainerModule((bind, unbind, isBound, rebind) => {
     bind(LanguageClientProviderImpl).toSelf().inSingletonScope();
     rebind(LanguageClientProvider).toService(LanguageClientProviderImpl);
     bind(ContextKeyService).to(ContextKeyServiceImpl).inSingletonScope();
+
+    bind(PluginDebugService).toSelf().inSingletonScope();
+    rebind(DebugService).toService(PluginDebugService);
+
+    bind(PluginDebugSessionContributionRegistry).toSelf().inSingletonScope();
+    rebind(DebugSessionContributionRegistry).toService(PluginDebugSessionContributionRegistry);
 });
diff --git a/packages/plugin-ext/src/plugin/command-registry.ts b/packages/plugin-ext/src/plugin/command-registry.ts
index e84bbdb24dad9..d7c3f1c7100d7 100644
--- a/packages/plugin-ext/src/plugin/command-registry.ts
+++ b/packages/plugin-ext/src/plugin/command-registry.ts
@@ -31,9 +31,15 @@ export class CommandRegistryImpl implements CommandRegistryExt {
 
     private readonly converter: CommandsConverter;
 
+    // tslint:disable-next-line:no-any
+    private static EMPTY_HANDLER(...args: any[]): Promise<any> { return Promise.resolve(undefined); }
+
     constructor(rpc: RPCProtocol) {
         this.proxy = rpc.getProxy(Ext.COMMAND_REGISTRY_MAIN);
         this.converter = new CommandsConverter(this);
+
+        // register internal VS Code commands
+        this.registerHandler('vscode.previewHtml', CommandRegistryImpl.EMPTY_HANDLER);
     }
 
     getConverter(): CommandsConverter {
@@ -50,6 +56,7 @@ export class CommandRegistryImpl implements CommandRegistryExt {
         this.proxy.$registerCommand(command);
 
         return Disposable.create(() => {
+            this.commands.delete(command.id);
             this.proxy.$unregisterCommand(command.id);
         });
 
@@ -61,6 +68,7 @@ export class CommandRegistryImpl implements CommandRegistryExt {
         }
         this.commands.set(commandId, handler);
         return Disposable.create(() => {
+            this.commands.delete(commandId);
             this.proxy.$unregisterCommand(commandId);
         });
     }
diff --git a/packages/plugin-ext/src/plugin/node/debug/debug.ts b/packages/plugin-ext/src/plugin/node/debug/debug.ts
new file mode 100644
index 0000000000000..12684d0017a09
--- /dev/null
+++ b/packages/plugin-ext/src/plugin/node/debug/debug.ts
@@ -0,0 +1,287 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+import { Emitter } from '@theia/core/lib/common/event';
+import { Disposable } from '../../types-impl';
+import { Breakpoint } from '../../../api/model';
+import { RPCProtocol } from '../../../api/rpc-protocol';
+import {
+    PLUGIN_RPC_CONTEXT as Ext,
+    DebugMain,
+    DebugExt
+} from '../../../api/plugin-api';
+import * as theia from '@theia/plugin';
+import uuid = require('uuid');
+import { IJSONSchema, IJSONSchemaSnippet } from '@theia/core/lib/common/json-schema';
+import { DebuggerDescription } from '@theia/debug/lib/common/debug-service';
+import { DebugProtocol } from 'vscode-debugprotocol';
+import { DebuggerContribution } from '../../../common';
+import { DebugAdapterSessionImpl } from '@theia/debug/lib/node/debug-adapter-session';
+import { ChildProcess, spawn, fork } from 'child_process';
+import { ConnectionExtImpl } from '../../connection-ext';
+import { CommandRegistryImpl } from '../../command-registry';
+import { PluginWebSocketChannel } from '../../../common/connection';
+import { PluginDebugAdapterContribution } from './plugin-debug-adapter-contribution';
+import { CommunicationProvider, DebugAdapterExecutable } from '@theia/debug/lib/common/debug-model';
+
+// tslint:disable:no-any
+
+/**
+ * It is supposed to work at node.
+ */
+export class DebugExtImpl implements DebugExt {
+    // debug sessions by sessionId
+    private debugSessions = new Map<string, PluginDebugAdapterSession>();
+
+    // contributions by contributorId
+    private contributions = new Map<string, PluginDebugAdapterContribution>();
+
+    private connectionExt: ConnectionExtImpl;
+    private commandRegistryExt: CommandRegistryImpl;
+
+    private proxy: DebugMain;
+    private readonly onDidChangeBreakpointsEmitter = new Emitter<theia.BreakpointsChangeEvent>();
+    private readonly onDidChangeActiveDebugSessionEmitter = new Emitter<theia.DebugSession | undefined>();
+    private readonly onDidTerminateDebugSessionEmitter = new Emitter<theia.DebugSession>();
+    private readonly onDidStartDebugSessionEmitter = new Emitter<theia.DebugSession>();
+    private readonly onDidReceiveDebugSessionCustomEmitter = new Emitter<theia.DebugSessionCustomEvent>();
+
+    activeDebugSession: theia.DebugSession | undefined;
+    activeDebugConsole: theia.DebugConsole;
+    breakpoints: theia.Breakpoint[] = [];
+
+    constructor(rpc: RPCProtocol) {
+        this.proxy = rpc.getProxy(Ext.DEBUG_MAIN);
+        this.activeDebugConsole = {
+            append: (value: string) => this.proxy.$appendToDebugConsole(value),
+            appendLine: (value: string) => this.proxy.$appendLineToDebugConsole(value)
+        };
+    }
+
+    inject(connectionExt: ConnectionExtImpl, commandRegistryExt: CommandRegistryImpl) {
+        this.connectionExt = connectionExt;
+        this.commandRegistryExt = commandRegistryExt;
+    }
+
+    get onDidReceiveDebugSessionCustomEvent(): theia.Event<theia.DebugSessionCustomEvent> {
+        return this.onDidReceiveDebugSessionCustomEmitter.event;
+    }
+
+    get onDidChangeActiveDebugSession(): theia.Event<theia.DebugSession | undefined> {
+        return this.onDidChangeActiveDebugSessionEmitter.event;
+    }
+
+    get onDidTerminateDebugSession(): theia.Event<theia.DebugSession> {
+        return this.onDidTerminateDebugSessionEmitter.event;
+    }
+
+    get onDidStartDebugSession(): theia.Event<theia.DebugSession> {
+        return this.onDidStartDebugSessionEmitter.event;
+    }
+
+    get onDidChangeBreakpoints(): theia.Event<theia.BreakpointsChangeEvent> {
+        return this.onDidChangeBreakpointsEmitter.event;
+    }
+
+    addBreakpoints(breakpoints: theia.Breakpoint[]): void {
+        this.proxy.$addBreakpoints(breakpoints);
+    }
+
+    removeBreakpoints(breakpoints: theia.Breakpoint[]): void {
+        this.proxy.$removeBreakpoints(breakpoints);
+    }
+
+    startDebugging(folder: theia.WorkspaceFolder | undefined, nameOrConfiguration: string | theia.DebugConfiguration): PromiseLike<boolean> {
+        return this.proxy.$startDebugging(folder, nameOrConfiguration);
+    }
+
+    registerDebugConfigurationProvider(
+        debugType: string,
+        provider: theia.DebugConfigurationProvider,
+        debuggerContribution: DebuggerContribution,
+        pluginPath: string): Disposable {
+
+        const contributionId = uuid.v4();
+        const adapterContribution = new PluginDebugAdapterContribution(
+            debugType,
+            provider,
+            debuggerContribution,
+            this.commandRegistryExt,
+            pluginPath);
+        this.contributions.set(contributionId, adapterContribution);
+
+        const description: DebuggerDescription = { type: debugType, label: debuggerContribution.label || debugType };
+        this.proxy.$registerDebugConfigurationProvider(contributionId, description);
+
+        return Disposable.create(() => {
+            this.contributions.delete(contributionId);
+            this.proxy.$unregisterDebugConfigurationProvider(contributionId);
+        });
+    }
+
+    // tslint:disable-next-line:no-any
+    $onSessionCustomEvent(sessionId: string, event: string, body?: any): void {
+        const session = this.debugSessions.get(sessionId);
+        if (session) {
+            this.onDidReceiveDebugSessionCustomEmitter.fire({ event, body, session });
+        }
+    }
+
+    $sessionDidCreate(sessionId: string): void {
+        const session = this.debugSessions.get(sessionId);
+        if (session) {
+            this.onDidStartDebugSessionEmitter.fire(session);
+        }
+    }
+
+    $sessionDidDestroy(sessionId: string): void {
+        const session = this.debugSessions.get(sessionId);
+        if (session) {
+            this.onDidTerminateDebugSessionEmitter.fire(session);
+        }
+    }
+
+    $sessionDidChange(sessionId: string | undefined): void {
+        const activeDebugSession = sessionId ? this.debugSessions.get(sessionId) : undefined;
+        this.onDidChangeActiveDebugSessionEmitter.fire(activeDebugSession);
+    }
+
+    $breakpointsDidChange(all: Breakpoint[], added: Breakpoint[], removed: Breakpoint[], changed: Breakpoint[]): void {
+        this.breakpoints = all;
+        this.onDidChangeBreakpointsEmitter.fire({ added, removed, changed });
+    }
+
+    async $createDebugSession(contributionId: string, debugConfiguration: theia.DebugConfiguration): Promise<string> {
+        const adapterContribution = this.contributions.get(contributionId);
+        if (!adapterContribution) {
+            throw new Error(`Debug adapter contribution '${contributionId}' not found.`);
+        }
+
+        const executable = await adapterContribution.provideDebugAdapterExecutable(debugConfiguration);
+        const communicationProvider = startDebugAdapter(executable);
+
+        const sessionId = uuid.v4();
+        const session = new PluginDebugAdapterSession(
+            sessionId,
+            debugConfiguration,
+            communicationProvider,
+            (command: string, args?: any) => this.proxy.$customRequest(command, args));
+        this.debugSessions.set(sessionId, session);
+
+        const connection = await this.connectionExt!.ensureConnection(sessionId);
+        session.start(new PluginWebSocketChannel(connection));
+
+        return sessionId;
+    }
+
+    async $terminateDebugSession(sessionId: string): Promise<void> {
+        const debugAdapterSession = this.debugSessions.get(sessionId);
+        if (debugAdapterSession) {
+            this.debugSessions.delete(sessionId);
+            return debugAdapterSession.stop();
+        }
+    }
+
+    async $getSupportedLanguages(contributionId: string): Promise<string[]> {
+        const contribution = this.contributions.get(contributionId);
+        if (!contribution) {
+            throw new Error(`Debug adapter contribution '${contributionId}' not found.`);
+        }
+
+        return contribution.getSupportedLanguages();
+    }
+
+    async $getSchemaAttributes(contributionId: string): Promise<IJSONSchema[]> {
+        const contribution = this.contributions.get(contributionId);
+        if (!contribution) {
+            throw new Error(`Debug adapter contribution '${contributionId}' not found.`);
+        }
+
+        return contribution.getSchemaAttributes();
+    }
+
+    async $getConfigurationSnippets(contributionId: string): Promise<IJSONSchemaSnippet[]> {
+        const contribution = this.contributions.get(contributionId);
+        if (!contribution) {
+            throw new Error(`Debug adapter contribution '${contributionId}' not found.`);
+        }
+
+        return contribution.getConfigurationSnippets();
+    }
+
+    async $provideDebugConfigurations(contributionId: string, folder: string | undefined): Promise<theia.DebugConfiguration[]> {
+        const contribution = this.contributions.get(contributionId);
+        if (!contribution) {
+            throw new Error(`Debug adapter contribution '${contributionId}' not found.`);
+        }
+
+        return contribution.provideDebugConfigurations(undefined);
+    }
+
+    async $resolveDebugConfigurations(
+        contributionId: string,
+        debugConfiguration: theia.DebugConfiguration,
+        folder: string | undefined): Promise<theia.DebugConfiguration | undefined> {
+
+        const contribution = this.contributions.get(contributionId);
+        if (!contribution) {
+            throw new Error(`Debug adapter contribution '${contributionId}' not found.`);
+        }
+
+        return contribution.resolveDebugConfiguration(debugConfiguration, folder);
+    }
+}
+
+/**
+ * Server debug session for plugin contribution.
+ */
+class PluginDebugAdapterSession extends DebugAdapterSessionImpl implements theia.DebugSession {
+    readonly type: string;
+    readonly name: string;
+
+    constructor(
+        readonly id: string,
+        readonly configuration: theia.DebugConfiguration,
+        readonly communicationProvider: CommunicationProvider,
+        readonly customRequest: (command: string, args?: any) => Promise<DebugProtocol.Response>) {
+
+        super(id, communicationProvider);
+
+        this.type = configuration.type;
+        this.name = configuration.name;
+    }
+}
+
+/**
+ * Starts debug adapter process.
+ */
+function startDebugAdapter(executable: DebugAdapterExecutable): CommunicationProvider {
+    let childProcess: ChildProcess;
+    if ('command' in executable) {
+        const { command, args } = executable;
+        childProcess = spawn(command, args, { stdio: ['pipe', 'pipe', 2] }) as ChildProcess;
+    } else if ('modulePath' in executable) {
+        const { modulePath, args } = executable;
+        childProcess = fork(modulePath, args, { stdio: ['pipe', 'pipe', 2, 'ipc'] });
+    } else {
+        throw new Error(`It is not possible to launch debug adapter with the command: ${JSON.stringify(executable)}`);
+    }
+
+    return {
+        input: childProcess.stdin,
+        output: childProcess.stdout,
+        dispose: () => childProcess.kill()
+    };
+}
diff --git a/packages/plugin-ext/src/plugin/node/debug/plugin-debug-adapter-contribution.ts b/packages/plugin-ext/src/plugin/node/debug/plugin-debug-adapter-contribution.ts
new file mode 100644
index 0000000000000..36ad7a067dc94
--- /dev/null
+++ b/packages/plugin-ext/src/plugin/node/debug/plugin-debug-adapter-contribution.ts
@@ -0,0 +1,100 @@
+/********************************************************************************
+ * Copyright (C) 2018 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import * as theia from '@theia/plugin';
+import * as path from 'path';
+import { DebugConfiguration } from '@theia/debug/lib/common/debug-configuration';
+import { PlatformSpecificAdapterContribution, DebuggerContribution } from '../../../common';
+import { CommandRegistryImpl } from '../../command-registry';
+import { IJSONSchemaSnippet, IJSONSchema } from '@theia/core/lib/common/json-schema';
+import { isWindows, isOSX } from '@theia/core/lib/common/os';
+import { DebugAdapterExecutable } from '@theia/debug/lib/common/debug-model';
+
+export class PluginDebugAdapterContribution {
+    constructor(
+        protected readonly debugType: string,
+        protected readonly provider: theia.DebugConfigurationProvider,
+        protected readonly debuggerContribution: DebuggerContribution,
+        protected readonly commandRegistryExt: CommandRegistryImpl,
+        protected readonly pluginPath: string) {
+    }
+
+    async provideDebugConfigurations(workspaceFolderUri?: string): Promise<DebugConfiguration[]> {
+        if (this.provider.provideDebugConfigurations) {
+            return await this.provider.provideDebugConfigurations(undefined) || [];
+        }
+
+        return [];
+    }
+
+    async resolveDebugConfiguration(config: DebugConfiguration, workspaceFolderUri?: string): Promise<DebugConfiguration | undefined> {
+        if (this.provider.resolveDebugConfiguration) {
+            return this.provider.resolveDebugConfiguration(undefined, config);
+        }
+
+        return config;
+    }
+
+    async getSupportedLanguages(): Promise<string[]> {
+        return this.debuggerContribution.languages || [];
+    }
+
+    async provideDebugAdapterExecutable(debugConfiguration: theia.DebugConfiguration): Promise<DebugAdapterExecutable> {
+        if (this.debuggerContribution.adapterExecutableCommand) {
+            return await this.commandRegistryExt.executeCommand(this.debuggerContribution.adapterExecutableCommand, []) as DebugAdapterExecutable;
+        }
+
+        const info = this.toPlatformInfo(this.debuggerContribution);
+        let program = (info && info.program || this.debuggerContribution.program);
+        if (!program) {
+            throw new Error('It is not possible to provide debug adapter executable. Program not found.');
+        }
+        program = path.join(this.pluginPath, program);
+        const programArgs = info && info.args || this.debuggerContribution.args || [];
+        let runtime = info && info.runtime || this.debuggerContribution.runtime;
+        if (runtime && runtime.indexOf('./') === 0) {
+            runtime = path.join(this.pluginPath, runtime);
+        }
+        const runtimeArgs = info && info.runtimeArgs || this.debuggerContribution.runtimeArgs || [];
+        const command = runtime ? runtime : program;
+        const args = runtime ? [...runtimeArgs, program, ...programArgs] : programArgs;
+        return {
+            command,
+            args
+        };
+    }
+
+    async getSchemaAttributes(): Promise<IJSONSchema[]> {
+        return this.debuggerContribution.configurationAttributes || [];
+    }
+
+    async getConfigurationSnippets(): Promise<IJSONSchemaSnippet[]> {
+        return this.debuggerContribution.configurationSnippets || [];
+    }
+
+    protected toPlatformInfo(executable: DebuggerContribution): PlatformSpecificAdapterContribution | undefined {
+        if (isWindows && !process.env.hasOwnProperty('PROCESSOR_ARCHITEW6432')) {
+            return executable.winx86 || executable.win || executable.windows;
+        }
+        if (isWindows) {
+            return executable.win || executable.windows;
+        }
+        if (isOSX) {
+            return executable.osx;
+        }
+        return executable.linux;
+    }
+}
diff --git a/packages/plugin-ext/src/plugin/plugin-context.ts b/packages/plugin-ext/src/plugin/plugin-context.ts
index 3b5945319f842..649105818ebc0 100644
--- a/packages/plugin-ext/src/plugin/plugin-context.ts
+++ b/packages/plugin-ext/src/plugin/plugin-context.ts
@@ -84,7 +84,10 @@ import {
     TaskPanelKind,
     TaskRevealKind,
     TaskGroup,
-    Task
+    Task,
+    Breakpoint,
+    SourceBreakpoint,
+    FunctionBreakpoint
 } from './types-impl';
 import { SymbolKind } from '../api/model';
 import { EditorsAndDocumentsExtImpl } from './editors-and-documents';
@@ -107,12 +110,14 @@ import { LanguagesContributionExtImpl } from './languages-contribution-ext';
 import { ConnectionExtImpl } from './connection-ext';
 import { WebviewsExtImpl } from './webviews';
 import { TasksExtImpl } from './tasks/tasks';
+import { DebugExtImpl } from './node/debug/debug';
+import { DebuggerContribution } from '../common';
 
 export function createAPIFactory(
     rpc: RPCProtocol,
     pluginManager: PluginManager,
     envExt: EnvExtImpl,
-    connectionExt: ConnectionExtImpl,
+    debugExt: DebugExtImpl,
     preferenceRegistryExt: PreferenceRegistryExtImpl): PluginAPIFactory {
 
     const commandRegistry = rpc.set(MAIN_RPC_CONTEXT.COMMAND_REGISTRY_EXT, new CommandRegistryImpl(rpc));
@@ -133,10 +138,12 @@ export function createAPIFactory(
     const treeViewsExt = rpc.set(MAIN_RPC_CONTEXT.TREE_VIEWS_EXT, new TreeViewsExtImpl(rpc, commandRegistry));
     const webviewExt = rpc.set(MAIN_RPC_CONTEXT.WEBVIEWS_EXT, new WebviewsExtImpl(rpc));
     const tasksExt = rpc.set(MAIN_RPC_CONTEXT.TASKS_EXT, new TasksExtImpl(rpc));
-    rpc.set(MAIN_RPC_CONTEXT.CONNECTION_EXT, new ConnectionExtImpl(rpc));
-    rpc.set(MAIN_RPC_CONTEXT.CONNECTION_EXT, connectionExt);
+    const connectionExt = rpc.set(MAIN_RPC_CONTEXT.CONNECTION_EXT, new ConnectionExtImpl(rpc));
     const languagesContributionExt = rpc.set(MAIN_RPC_CONTEXT.LANGUAGES_CONTRIBUTION_EXT, new LanguagesContributionExtImpl(rpc, connectionExt));
 
+    debugExt.inject(connectionExt, commandRegistry);
+    rpc.set(MAIN_RPC_CONTEXT.DEBUG_EXT, debugExt);
+
     return function (plugin: InternalPlugin): typeof theia {
         const commands: typeof theia.commands = {
             // tslint:disable-next-line:no-any
@@ -497,17 +504,51 @@ export function createAPIFactory(
         };
 
         const debug: typeof theia.debug = {
-            onDidChangeActiveDebugSession(listener, thisArg?, disposables?) {
-                // FIXME: to implement
-                return new Disposable(() => { });
+            get activeDebugSession(): theia.DebugSession | undefined {
+                return debugExt.activeDebugSession;
             },
-            onDidTerminateDebugSession(listener, thisArg?, disposables?) {
-                // FIXME: to implement
-                return new Disposable(() => { });
+            get activeDebugConsole(): theia.DebugConsole {
+                return debugExt.activeDebugConsole;
             },
-            registerDebugConfigurationProvider(debugType: string, provider: theia.DebugConfigurationProvider): theia.Disposable {
-                // FIXME: to implement
-                return new Disposable(() => { });
+            get breakpoints(): theia.Breakpoint[] {
+                return debugExt.breakpoints;
+            },
+            get onDidChangeActiveDebugSession(): theia.Event<theia.DebugSession | undefined> {
+                return debugExt.onDidChangeActiveDebugSession;
+            },
+            get onDidStartDebugSession(): theia.Event<theia.DebugSession> {
+                return debugExt.onDidStartDebugSession;
+            },
+            get onDidReceiveDebugSessionCustomEvent(): theia.Event<theia.DebugSessionCustomEvent> {
+                return debugExt.onDidReceiveDebugSessionCustomEvent;
+            },
+            get onDidTerminateDebugSession(): theia.Event<theia.DebugSession> {
+                return debugExt.onDidTerminateDebugSession;
+            },
+            get onDidChangeBreakpoints(): theia.Event<theia.BreakpointsChangeEvent> {
+                return debugExt.onDidChangeBreakpoints;
+            },
+            registerDebugConfigurationProvider(debugType: string, provider: theia.DebugConfigurationProvider): Disposable {
+                const debuggersContribution = plugin.model.contributes && plugin.model.contributes.debuggers;
+                if (debuggersContribution) {
+                    const contribution = debuggersContribution.filter((value: DebuggerContribution) => value.type === debugType)[0];
+                    if (contribution) {
+                        console.info(`Registered debug contribution provider: '${debugType}'`);
+                        return debugExt.registerDebugConfigurationProvider(debugType, provider, contribution, plugin.pluginFolder);
+                    }
+                }
+
+                console.warn(`There is no package contribution with type ${debugType}`);
+                return Disposable.create(() => { });
+            },
+            startDebugging(folder: theia.WorkspaceFolder | undefined, nameOrConfiguration: string | theia.DebugConfiguration): Thenable<boolean> {
+                return debugExt.startDebugging(folder, nameOrConfiguration);
+            },
+            addBreakpoints(breakpoints: theia.Breakpoint[]): void {
+                debugExt.addBreakpoints(breakpoints);
+            },
+            removeBreakpoints(breakpoints: theia.Breakpoint[]): void {
+                debugExt.removeBreakpoints(breakpoints);
             }
         };
 
@@ -592,7 +633,10 @@ export function createAPIFactory(
             TaskRevealKind,
             TaskPanelKind,
             TaskGroup,
-            Task
+            Task,
+            Breakpoint,
+            SourceBreakpoint,
+            FunctionBreakpoint
         };
     };
 }
diff --git a/packages/plugin-ext/src/plugin/plugin-manager.ts b/packages/plugin-ext/src/plugin/plugin-manager.ts
index bdc379c6a3240..e65c2343144cb 100644
--- a/packages/plugin-ext/src/plugin/plugin-manager.ts
+++ b/packages/plugin-ext/src/plugin/plugin-manager.ts
@@ -121,6 +121,8 @@ export class PluginManagerExtImpl implements PluginManagerExt, PluginManager {
         const pluginContext: theia.PluginContext = {
             extensionPath: plugin.pluginFolder,
             subscriptions: subscriptions,
+            globalState: new MementoImpl(),
+            workspaceState: new MementoImpl(),
             asAbsolutePath: asAbsolutePath,
             logPath: logPath,
             storagePath: storagePath,
@@ -181,3 +183,17 @@ function getGlobal() {
     // tslint:disable-next-line:no-null-keyword
     return typeof self === 'undefined' ? typeof global === 'undefined' ? null : global : self;
 }
+
+class MementoImpl<T> implements theia.Memento {
+    private readonly m = new Map<string, T>();
+
+    get(key: string, defaultValue?: T): T | undefined {
+        const value = this.m.get(key);
+        return value || defaultValue;
+    }
+
+    update(key: string, value: T): PromiseLike<void> {
+        this.m.set(key, value);
+        return Promise.resolve(undefined);
+    }
+}
diff --git a/packages/plugin-ext/src/plugin/types-impl.ts b/packages/plugin-ext/src/plugin/types-impl.ts
index 833df5f0ed284..a7e77c51ae2c4 100644
--- a/packages/plugin-ext/src/plugin/types-impl.ts
+++ b/packages/plugin-ext/src/plugin/types-impl.ts
@@ -1652,3 +1652,68 @@ export class Task {
         }
     }
 }
+
+/**
+ * The base class of all breakpoint types.
+ */
+export class Breakpoint {
+    /**
+     * Is breakpoint enabled.
+     */
+    enabled: boolean;
+    /**
+     * An optional expression for conditional breakpoints.
+     */
+    condition?: string;
+    /**
+     * An optional expression that controls how many hits of the breakpoint are ignored.
+     */
+    hitCondition?: string;
+    /**
+     * An optional message that gets logged when this breakpoint is hit. Embedded expressions within {} are interpolated by the debug adapter.
+     */
+    logMessage?: string;
+
+    protected constructor(enabled?: boolean, condition?: string, hitCondition?: string, logMessage?: string) {
+        this.enabled = enabled || false;
+        this.condition = condition;
+        this.hitCondition = hitCondition;
+        this.logMessage = logMessage;
+    }
+}
+
+/**
+ * A breakpoint specified by a source location.
+ */
+export class SourceBreakpoint extends Breakpoint {
+    /**
+     * The source and line position of this breakpoint.
+     */
+    location: Location;
+
+    /**
+     * Create a new breakpoint for a source location.
+     */
+    constructor(location: Location, enabled?: boolean, condition?: string, hitCondition?: string, logMessage?: string) {
+        super(enabled, condition, hitCondition, logMessage);
+        this.location = location;
+    }
+}
+
+/**
+ * A breakpoint specified by a function name.
+ */
+export class FunctionBreakpoint extends Breakpoint {
+    /**
+     * The name of the function to which this breakpoint is attached.
+     */
+    functionName: string;
+
+    /**
+     * Create a new function breakpoint.
+     */
+    constructor(functionName: string, enabled?: boolean, condition?: string, hitCondition?: string, logMessage?: string) {
+        super(enabled, condition, hitCondition, logMessage);
+        this.functionName = functionName;
+    }
+}
diff --git a/packages/plugin/src/theia.d.ts b/packages/plugin/src/theia.d.ts
index b4e70106ecb42..0005e7176597d 100644
--- a/packages/plugin/src/theia.d.ts
+++ b/packages/plugin/src/theia.d.ts
@@ -612,22 +612,22 @@ declare module '@theia/plugin' {
         provideDefinition(document: TextDocument, position: Position, token: CancellationToken | undefined): ProviderResult<Definition | DefinitionLink[]>;
     }
 
-	/**
-	 * The implementation provider interface defines the contract between extensions and
-	 * the go to implementation feature.
-	 */
-	export interface ImplementationProvider {
+    /**
+     * The implementation provider interface defines the contract between extensions and
+     * the go to implementation feature.
+     */
+    export interface ImplementationProvider {
 
-		/**
-		 * Provide the implementations of the symbol at the given position and document.
-		 *
-		 * @param document The document in which the command was invoked.
-		 * @param position The position at which the command was invoked.
-		 * @param token A cancellation token.
-		 * @return A definition or a thenable that resolves to such. The lack of a result can be
-		 * signaled by returning `undefined` or `null`.
-		 */
-		provideImplementation(document: TextDocument, position: Position, token: CancellationToken): ProviderResult<Definition | DefinitionLink[]>;
+        /**
+         * Provide the implementations of the symbol at the given position and document.
+         *
+         * @param document The document in which the command was invoked.
+         * @param position The position at which the command was invoked.
+         * @param token A cancellation token.
+         * @return A definition or a thenable that resolves to such. The lack of a result can be
+         * signaled by returning `undefined` or `null`.
+         */
+        provideImplementation(document: TextDocument, position: Position, token: CancellationToken): ProviderResult<Definition | DefinitionLink[]>;
     }
 
     /**
@@ -2352,6 +2352,18 @@ declare module '@theia/plugin' {
          */
         subscriptions: { dispose(): any }[];
 
+        /**
+         * A memento object that stores state in the context
+         * of the currently opened [workspace](#workspace.workspaceFolders).
+         */
+        workspaceState: Memento;
+
+        /**
+         * A memento object that stores state independent
+         * of the current opened [workspace](#workspace.workspaceFolders).
+         */
+        globalState: Memento;
+
         /**
          * The absolute file path of the directory containing the extension.
          */
@@ -5905,14 +5917,17 @@ declare module '@theia/plugin' {
          * The type of the debug session.
          */
         type: string;
+
         /**
          * The name of the debug session.
          */
         name: string;
+
         /**
          * The request type of the debug session.
          */
         request: string;
+
         /**
          * Additional debug type specific properties.
          */
@@ -5920,8 +5935,8 @@ declare module '@theia/plugin' {
     }
 
     /**
-     * A debug session.
-     */
+ * A debug session.
+ */
     export interface DebugSession {
 
         /**
@@ -5945,6 +5960,26 @@ declare module '@theia/plugin' {
         customRequest(command: string, args?: any): PromiseLike<any>;
     }
 
+    /**
+     * A custom Debug Adapter Protocol event received from a [debug session](#DebugSession).
+     */
+    export interface DebugSessionCustomEvent {
+        /**
+         * The [debug session](#DebugSession) for which the custom event was received.
+         */
+        session: DebugSession;
+
+        /**
+         * Type of event.
+         */
+        event: string;
+
+        /**
+         * Event specific information.
+         */
+        body?: any;
+    }
+
     /**
      * A debug configuration provider allows to add the initial debug configurations to a newly created launch.json
      * and to resolve a launch configuration before it is used to start a new debug session.
@@ -5960,6 +5995,7 @@ declare module '@theia/plugin' {
          * @return An array of [debug configurations](#DebugConfiguration).
          */
         provideDebugConfigurations?(folder: WorkspaceFolder | undefined, token?: CancellationToken): ProviderResult<DebugConfiguration[]>;
+
         /**
          * Resolves a [debug configuration](#DebugConfiguration) by filling in missing values or by adding/changing/removing attributes.
          * If more than one debug configuration provider is registered for the same type, the resolveDebugConfiguration calls are chained
@@ -5975,11 +6011,122 @@ declare module '@theia/plugin' {
         resolveDebugConfiguration?(folder: WorkspaceFolder | undefined, debugConfiguration: DebugConfiguration, token?: CancellationToken): ProviderResult<DebugConfiguration>;
     }
 
+    /**
+     * Represents the debug console.
+     */
+    export interface DebugConsole {
+        /**
+         * Append the given value to the debug console.
+         *
+         * @param value A string, falsy values will not be printed.
+         */
+        append(value: string): void;
+
+        /**
+         * Append the given value and a line feed character
+         * to the debug console.
+         *
+         * @param value A string, falsy values will be printed.
+         */
+        appendLine(value: string): void;
+    }
+
+    /**
+     * An event describing the changes to the set of [breakpoints](#Breakpoint).
+     */
+    export interface BreakpointsChangeEvent {
+        /**
+         * Added breakpoints.
+         */
+        readonly added: Breakpoint[];
+
+        /**
+         * Removed breakpoints.
+         */
+        readonly removed: Breakpoint[];
+
+        /**
+         * Changed breakpoints.
+         */
+        readonly changed: Breakpoint[];
+    }
+
+    /**
+     * The base class of all breakpoint types.
+     */
+    export class Breakpoint {
+        /**
+         * Is breakpoint enabled.
+         */
+        readonly enabled: boolean;
+        /**
+         * An optional expression for conditional breakpoints.
+         */
+        readonly condition?: string;
+        /**
+         * An optional expression that controls how many hits of the breakpoint are ignored.
+         */
+        readonly hitCondition?: string;
+        /**
+         * An optional message that gets logged when this breakpoint is hit. Embedded expressions within {} are interpolated by the debug adapter.
+         */
+        readonly logMessage?: string;
+
+        protected constructor(enabled?: boolean, condition?: string, hitCondition?: string, logMessage?: string);
+    }
+
+    /**
+     * A breakpoint specified by a source location.
+     */
+    export class SourceBreakpoint extends Breakpoint {
+        /**
+         * The source and line position of this breakpoint.
+         */
+        readonly location: Location;
+
+        /**
+         * Create a new breakpoint for a source location.
+         */
+        constructor(location: Location, enabled?: boolean, condition?: string, hitCondition?: string, logMessage?: string);
+    }
+
+    /**
+     * A breakpoint specified by a function name.
+     */
+    export class FunctionBreakpoint extends Breakpoint {
+        /**
+         * The name of the function to which this breakpoint is attached.
+         */
+        readonly functionName: string;
+
+        /**
+         * Create a new function breakpoint.
+         */
+        constructor(functionName: string, enabled?: boolean, condition?: string, hitCondition?: string, logMessage?: string);
+    }
+
     /**
      * Namespace for debug functionality.
      */
     export namespace debug {
 
+        /**
+         * The currently active [debug session](#DebugSession) or `undefined`. The active debug session is the one
+         * represented by the debug action floating window or the one currently shown in the drop down menu of the debug action floating window.
+         * If no debug session is active, the value is `undefined`.
+         */
+        export let activeDebugSession: DebugSession | undefined;
+
+        /**
+         * The currently active [debug console](#DebugConsole).
+         */
+        export let activeDebugConsole: DebugConsole;
+
+        /**
+         * List of breakpoints.
+         */
+        export let breakpoints: Breakpoint[];
+
         /**
          * An [event](#Event) which fires when the [active debug session](#debug.activeDebugSession)
          * has changed. *Note* that the event also fires when the active debug session changes
@@ -5987,11 +6134,26 @@ declare module '@theia/plugin' {
          */
         export const onDidChangeActiveDebugSession: Event<DebugSession | undefined>;
 
+        /**
+         * An [event](#Event) which fires when a new [debug session](#DebugSession) has been started.
+         */
+        export const onDidStartDebugSession: Event<DebugSession>;
+
+        /**
+         * An [event](#Event) which fires when a custom DAP event is received from the [debug session](#DebugSession).
+         */
+        export const onDidReceiveDebugSessionCustomEvent: Event<DebugSessionCustomEvent>;
+
         /**
          * An [event](#Event) which fires when a [debug session](#DebugSession) has terminated.
          */
         export const onDidTerminateDebugSession: Event<DebugSession>;
 
+        /**
+         * An [event](#Event) that is emitted when the set of breakpoints is added, removed, or changed.
+         */
+        export const onDidChangeBreakpoints: Event<BreakpointsChangeEvent>;
+
         /**
          * Register a [debug configuration provider](#DebugConfigurationProvider) for a specific debug type.
          * More than one provider can be registered for the same type.
@@ -6001,6 +6163,30 @@ declare module '@theia/plugin' {
          * @return A [disposable](#Disposable) that unregisters this provider when being disposed.
          */
         export function registerDebugConfigurationProvider(debugType: string, provider: DebugConfigurationProvider): Disposable;
+
+        /**
+         * Start debugging by using either a named launch or named compound configuration,
+         * or by directly passing a [DebugConfiguration](#DebugConfiguration).
+         * The named configurations are looked up in '.vscode/launch.json' found in the given folder.
+         * Before debugging starts, all unsaved files are saved and the launch configurations are brought up-to-date.
+         * Folder specific variables used in the configuration (e.g. '${workspaceFolder}') are resolved against the given folder.
+         * @param folder The [workspace folder](#WorkspaceFolder) for looking up named configurations and resolving variables or `undefined` for a non-folder setup.
+         * @param nameOrConfiguration Either the name of a debug or compound configuration or a [DebugConfiguration](#DebugConfiguration) object.
+         * @return A thenable that resolves when debugging could be successfully started.
+         */
+        export function startDebugging(folder: WorkspaceFolder | undefined, nameOrConfiguration: string | DebugConfiguration): PromiseLike<boolean>;
+
+        /**
+         * Add breakpoints.
+         * @param breakpoints The breakpoints to add.
+        */
+        export function addBreakpoints(breakpoints: Breakpoint[]): void;
+
+        /**
+         * Remove breakpoints.
+         * @param breakpoints The breakpoints to remove.
+         */
+        export function removeBreakpoints(breakpoints: Breakpoint[]): void;
     }
 
     /**
@@ -6273,7 +6459,7 @@ declare module '@theia/plugin' {
         Never = 3
     }
 
-    /** Controls how the task channel is used between tasks	 */
+    /** Controls how the task channel is used between tasks */
     export enum TaskPanelKind {
 
         /** Shares a panel with other tasks. This is the default. */
@@ -6408,4 +6594,37 @@ declare module '@theia/plugin' {
          */
         export function registerTaskProvider(type: string, provider: TaskProvider): Disposable;
     }
+
+    /**
+     * A memento represents a storage utility. It can store and retrieve
+     * values.
+     */
+    export interface Memento {
+
+        /**
+        * Return a value.
+        *
+        * @param key A string.
+        * @return The stored value or `undefined`.
+        */
+        get<T>(key: string): T | undefined;
+
+        /**
+         * Return a value.
+         *
+         * @param key A string.
+         * @param defaultValue A value that should be returned when there is no
+         * value (`undefined`) with the given key.
+         * @return The stored value or the defaultValue.
+         */
+        get<T>(key: string, defaultValue: T): T;
+
+        /**
+         * Store a value. The value must be JSON-stringifyable.
+         *
+         * @param key A string.
+         * @param value A value. MUST not contain cyclic references.
+         */
+        update(key: string, value: any): PromiseLike<void>;
+    }
 }