diff --git a/lib/api/core.dart b/lib/api/core.dart
index 8b18349d4f..814f0eac93 100644
--- a/lib/api/core.dart
+++ b/lib/api/core.dart
@@ -49,14 +49,16 @@ class ApiConnection {
 
   bool _isOpen = true;
 
-  Future<String> send(http.BaseRequest request) async {
+  Future<Map<String, dynamic>> send(http.BaseRequest request) async {
     assert(_isOpen);
     addAuth(request);
     final response = await _client.send(request);
     if (response.statusCode != 200) {
       throw Exception("error on ${request.method} ${request.url.path}: status ${response.statusCode}");
     }
-    return utf8.decode(await response.stream.toBytes());
+    final bytes = await response.stream.toBytes();
+    return jsonDecode(utf8.decode(bytes));
+    // TODO(#37): inspect response to throw structured errors
   }
 
   void close() {
@@ -65,7 +67,7 @@ class ApiConnection {
     _isOpen = false;
   }
 
-  Future<String> get(String route, Map<String, dynamic>? params) async {
+  Future<Map<String, dynamic>> get(String route, Map<String, dynamic>? params) async {
     final url = realmUrl.replace(
         path: "/api/v1/$route", queryParameters: encodeParameters(params));
     assert(debugLog("GET $url"));
@@ -73,7 +75,7 @@ class ApiConnection {
     return send(request);
   }
 
-  Future<String> post(String route, Map<String, dynamic>? params) async {
+  Future<Map<String, dynamic>> post(String route, Map<String, dynamic>? params) async {
     final url = realmUrl.replace(path: "/api/v1/$route");
     final request = http.Request('POST', url);
     if (params != null) {
@@ -82,7 +84,7 @@ class ApiConnection {
     return send(request);
   }
 
-  Future<String> postFileFromStream(String route, Stream<List<int>> content, int length, { String? filename }) async {
+  Future<Map<String, dynamic>> postFileFromStream(String route, Stream<List<int>> content, int length, { String? filename }) async {
     http.MultipartRequest request = http.MultipartRequest('POST', Uri.parse("$realmUrl/api/v1/$route"))
       ..files.add(http.MultipartFile('file', content, length, filename: filename));
     return send(request);
diff --git a/lib/api/route/account.dart b/lib/api/route/account.dart
index d730b198bf..ff536887e2 100644
--- a/lib/api/route/account.dart
+++ b/lib/api/route/account.dart
@@ -1,5 +1,3 @@
-import 'dart:convert';
-
 import 'package:json_annotation/json_annotation.dart';
 
 import '../core.dart';
@@ -12,7 +10,7 @@ Future<FetchApiKeyResult> fetchApiKey({
   required String username,
   required String password,
 }) async {
-  final String data;
+  final Map<String, dynamic> data;
   // TODO make this function testable by taking ApiConnection from caller
   final connection = ApiConnection.live(realmUrl: realmUrl);
   try {
@@ -24,8 +22,7 @@ Future<FetchApiKeyResult> fetchApiKey({
     connection.close();
   }
 
-  final json = jsonDecode(data);
-  return FetchApiKeyResult.fromJson(json);
+  return FetchApiKeyResult.fromJson(data);
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)
diff --git a/lib/api/route/events.dart b/lib/api/route/events.dart
index af961d92ac..556738a599 100644
--- a/lib/api/route/events.dart
+++ b/lib/api/route/events.dart
@@ -1,5 +1,3 @@
-import 'dart:convert';
-
 import 'package:json_annotation/json_annotation.dart';
 
 import '../core.dart';
@@ -21,8 +19,7 @@ Future<InitialSnapshot> registerQueue(ApiConnection connection) async {
       'user_settings_object': true,
     },
   });
-  final json = jsonDecode(data);
-  return InitialSnapshot.fromJson(json);
+  return InitialSnapshot.fromJson(data);
 }
 
 /// https://zulip.com/api/get-events
@@ -34,7 +31,7 @@ Future<GetEventsResult> getEvents(ApiConnection connection, {
     if (lastEventId != null) 'last_event_id': lastEventId,
     if (dontBlock != null) 'dont_block': dontBlock,
   });
-  return GetEventsResult.fromJson(jsonDecode(data));
+  return GetEventsResult.fromJson(data);
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)
diff --git a/lib/api/route/messages.dart b/lib/api/route/messages.dart
index 8411a04c51..1ea639b35f 100644
--- a/lib/api/route/messages.dart
+++ b/lib/api/route/messages.dart
@@ -1,5 +1,3 @@
-import 'dart:convert';
-
 import 'package:json_annotation/json_annotation.dart';
 
 import '../core.dart';
@@ -18,7 +16,7 @@ Future<GetMessagesResult> getMessages(ApiConnection connection, {
     'num_before': numBefore,
     'num_after': numAfter,
   });
-  return GetMessagesResult.fromJson(jsonDecode(data));
+  return GetMessagesResult.fromJson(data);
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)
@@ -79,7 +77,7 @@ Future<SendMessageResult> sendMessage(
     'topic': RawParameter(topic),
     'content': RawParameter(content),
   });
-  return SendMessageResult.fromJson(jsonDecode(data));
+  return SendMessageResult.fromJson(data);
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)
@@ -106,7 +104,7 @@ Future<UploadFileResult> uploadFile(
   required String filename,
 }) async {
   final data = await connection.postFileFromStream('user_uploads', content, length, filename: filename);
-  return UploadFileResult.fromJson(jsonDecode(data));
+  return UploadFileResult.fromJson(data);
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)
diff --git a/lib/api/route/realm.dart b/lib/api/route/realm.dart
index 191ab00643..1f366f5cc5 100644
--- a/lib/api/route/realm.dart
+++ b/lib/api/route/realm.dart
@@ -1,5 +1,3 @@
-import 'dart:convert';
-
 import 'package:json_annotation/json_annotation.dart';
 
 import '../core.dart';
@@ -20,7 +18,7 @@ part 'realm.g.dart';
 Future<GetServerSettingsResult> getServerSettings({
   required Uri realmUrl,
 }) async {
-  final String data;
+  final Map<String, dynamic> data;
   // TODO make this function testable by taking ApiConnection from caller
   final connection = ApiConnection.live(realmUrl: realmUrl);
   try {
@@ -29,8 +27,7 @@ Future<GetServerSettingsResult> getServerSettings({
     connection.close();
   }
 
-  final json = jsonDecode(data);
-  return GetServerSettingsResult.fromJson(json);
+  return GetServerSettingsResult.fromJson(data);
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)
diff --git a/lib/api/route/users.dart b/lib/api/route/users.dart
index a5a94d93ee..bb560c5418 100644
--- a/lib/api/route/users.dart
+++ b/lib/api/route/users.dart
@@ -1,5 +1,3 @@
-import 'dart:convert';
-
 import 'package:json_annotation/json_annotation.dart';
 
 import '../core.dart';
@@ -12,7 +10,7 @@ part 'users.g.dart';
 /// as a workaround on old servers.
 Future<GetOwnUserResult> getOwnUser(ApiConnection connection) async {
   final data = await connection.get('users/me', {});
-  return GetOwnUserResult.fromJson(jsonDecode(data));
+  return GetOwnUserResult.fromJson(data);
 }
 
 @JsonSerializable(fieldRename: FieldRename.snake)