diff --git a/docs/explanation/rooms.mdx b/docs/explanation/rooms.mdx
index 128f0432..ab1b66c3 100644
--- a/docs/explanation/rooms.mdx
+++ b/docs/explanation/rooms.mdx
@@ -119,9 +119,9 @@ Fishjam supports the following video codecs:
 - **H.264** — A hardware-accelerated codec offering superior performance. Used by default. Its availability varies by device, and it may not perform optimally at lower bitrates.
 - **VP8** — A software-based codec supported across all devices, ensuring maximum compatibility. Ideal for environments lacking hardware acceleration, such as Android emulators.
 
-Fishjam uses H.264 by default, however, to solve an issue with Android emulators, VP8 is set when you're using the Sandbox API.
+Fishjam uses H.264 by default. To solve an issue with Android emulators, the Sandbox API uses VP8 unless you pass the `videoCodec` query parameter (`vp8` or `h264`). Use H.264 if you want to [compose a room](../how-to/compositions/compose-a-fishjam-room) created with the Sandbox API.
 
-You can override the default codec by setting the `codec` parameter when [creating a room](../api/server/interfaces/RoomConfig#videocodec) using server SDKs.
+You can override the default codec by setting the `videoCodec` parameter when [creating a room](../api/server/interfaces/RoomConfig#videocodec) using server SDKs.
 
 We recommend using H.264 for production and VP8 for development as it works with Android emulators.
 
diff --git a/docs/how-to/backend/sandbox-api-testing.mdx b/docs/how-to/backend/sandbox-api-testing.mdx
index 69101006..5cc87cb2 100644
--- a/docs/how-to/backend/sandbox-api-testing.mdx
+++ b/docs/how-to/backend/sandbox-api-testing.mdx
@@ -78,6 +78,11 @@ You need both values for React/React Native apps:
 ### Optional parameters
 
 - `roomType` - Type of room to create (defaults to `conference`)
+- `videoCodec` - Video codec of the room: `vp8` (default) or `h264`. Accepted by both the peer and the livestream endpoints. Joining an existing room with a different codec returns `409 Conflict`; omit it to join a room regardless of its codec.
+
+```bash
+curl "$SANDBOX_API_URL?roomName=testRoom&peerName=testUser&videoCodec=h264"
+```
 
 ### Room types available