diff --git a/.changeset/nervous-comics-fetch.md b/.changeset/nervous-comics-fetch.md
new file mode 100644
index 0000000000..62063cf70a
--- /dev/null
+++ b/.changeset/nervous-comics-fetch.md
@@ -0,0 +1,7 @@
+---
+"@effect/platform": patch
+---
+
+ensure /platform HttpApp.toWebHandler runs Stream's with the current runtime
+
+Also add runtime options to HttpServerResponse.toWeb
diff --git a/packages/platform/src/HttpApp.ts b/packages/platform/src/HttpApp.ts
index 920b354769..8ef9df6e68 100644
--- a/packages/platform/src/HttpApp.ts
+++ b/packages/platform/src/HttpApp.ts
@@ -138,12 +138,12 @@ export const withPreResponseHandler = dual<
  */
 export const toWebHandlerRuntime = <R>(runtime: Runtime.Runtime<R>) => {
   const run = Runtime.runFork(runtime)
-  return <E>(self: Default<E, R | Scope.Scope>, middleware: HttpMiddleware | undefined) =>
+  return <E>(self: Default<E, R | Scope.Scope>, middleware?: HttpMiddleware | undefined) =>
   (request: Request): Promise<Response> =>
     new Promise((resolve) => {
       const fiber = run(Effect.provideService(
         toHandled(self, (request, response) => {
-          resolve(ServerResponse.toWeb(response, request.method === "HEAD"))
+          resolve(ServerResponse.toWeb(response, { withoutBody: request.method === "HEAD", runtime }))
           return Effect.void
         }, middleware),
         ServerRequest.HttpServerRequest,
diff --git a/packages/platform/src/HttpServerResponse.ts b/packages/platform/src/HttpServerResponse.ts
index 480e637139..f0a624d150 100644
--- a/packages/platform/src/HttpServerResponse.ts
+++ b/packages/platform/src/HttpServerResponse.ts
@@ -5,6 +5,7 @@ import type { ParseOptions } from "@effect/schema/AST"
 import type * as Schema from "@effect/schema/Schema"
 import type * as Effect from "effect/Effect"
 import type { Inspectable } from "effect/Inspectable"
+import type * as Runtime from "effect/Runtime"
 import type * as Stream from "effect/Stream"
 import type { Cookie, Cookies, CookiesError } from "./Cookies.js"
 import type * as PlatformError from "./Error.js"
@@ -353,4 +354,10 @@ export const setStatus: {
  * @since 1.0.0
  * @category conversions
  */
-export const toWeb: (response: HttpServerResponse, withoutBody?: boolean | undefined) => Response = internal.toWeb
+export const toWeb: (
+  response: HttpServerResponse,
+  options?: {
+    readonly withoutBody?: boolean | undefined
+    readonly runtime?: Runtime.Runtime<never> | undefined
+  }
+) => Response = internal.toWeb
diff --git a/packages/platform/src/internal/httpServerResponse.ts b/packages/platform/src/internal/httpServerResponse.ts
index 3971da7313..ef1ceff541 100644
--- a/packages/platform/src/internal/httpServerResponse.ts
+++ b/packages/platform/src/internal/httpServerResponse.ts
@@ -4,6 +4,7 @@ import * as Effect from "effect/Effect"
 import * as Effectable from "effect/Effectable"
 import { dual } from "effect/Function"
 import * as Inspectable from "effect/Inspectable"
+import * as Runtime from "effect/Runtime"
 import * as Stream from "effect/Stream"
 import * as Cookies from "../Cookies.js"
 import type * as PlatformError from "../Error.js"
@@ -504,7 +505,10 @@ export const setBody = dual<
 })
 
 /** @internal */
-export const toWeb = (response: ServerResponse.HttpServerResponse, withoutBody = false): Response => {
+export const toWeb = (response: ServerResponse.HttpServerResponse, options?: {
+  readonly withoutBody?: boolean | undefined
+  readonly runtime?: Runtime.Runtime<never> | undefined
+}): Response => {
   const headers = new globalThis.Headers(response.headers)
   if (!Cookies.isEmpty(response.cookies)) {
     const toAdd = Cookies.toSetCookieHeaders(response.cookies)
@@ -512,7 +516,7 @@ export const toWeb = (response: ServerResponse.HttpServerResponse, withoutBody =
       headers.append("set-cookie", header)
     }
   }
-  if (withoutBody) {
+  if (options?.withoutBody) {
     return new Response(undefined, {
       status: response.status,
       statusText: response.statusText as string,
@@ -544,7 +548,7 @@ export const toWeb = (response: ServerResponse.HttpServerResponse, withoutBody =
       })
     }
     case "Stream": {
-      return new Response(Stream.toReadableStream(body.stream), {
+      return new Response(Stream.toReadableStreamRuntime(body.stream, options?.runtime ?? Runtime.defaultRuntime), {
         status: response.status,
         statusText: response.statusText,
         headers
diff --git a/packages/platform/test/HttpApp.test.ts b/packages/platform/test/HttpApp.test.ts
index 28457ec35c..496ef41fd5 100644
--- a/packages/platform/test/HttpApp.test.ts
+++ b/packages/platform/test/HttpApp.test.ts
@@ -1,5 +1,5 @@
 import { HttpApp, HttpServerResponse } from "@effect/platform"
-import { Stream } from "effect"
+import { FiberRef, Runtime, Stream } from "effect"
 import { assert, describe, test } from "vitest"
 
 describe("Http/App", () => {
@@ -34,5 +34,17 @@ describe("Http/App", () => {
       const response = await handler(new Request("http://localhost:3000/"))
       assert.strictEqual(await response.text(), "foobar")
     })
+
+    test("stream runtime", async () => {
+      const handler = HttpApp.toWebHandlerRuntime(
+        Runtime.defaultRuntime.pipe(
+          Runtime.setFiberRef(FiberRef.currentConcurrency, 420)
+        )
+      )(HttpServerResponse.stream(
+        FiberRef.get(FiberRef.currentConcurrency).pipe(Stream.map(String), Stream.encodeText)
+      ))
+      const response = await handler(new Request("http://localhost:3000/"))
+      assert.strictEqual(await response.text(), "420")
+    })
   })
 })