diff --git a/packages/mobile-client/src/index.ts b/packages/mobile-client/src/index.ts
index 88a1005b6..0059d118e 100644
--- a/packages/mobile-client/src/index.ts
+++ b/packages/mobile-client/src/index.ts
@@ -123,6 +123,8 @@ export type {
   ConnectViewerConfig,
   RoomType,
   UseSandboxProps,
+  SandboxOptions,
+  VideoCodec,
   BandwidthLimits,
   Brand,
   DeviceError,
diff --git a/packages/react-client/src/hooks/useSandbox.ts b/packages/react-client/src/hooks/useSandbox.ts
index 57d54572d..7a082812f 100644
--- a/packages/react-client/src/hooks/useSandbox.ts
+++ b/packages/react-client/src/hooks/useSandbox.ts
@@ -1,5 +1,6 @@
 import { useCallback } from "react";
 
+import type { VideoCodec } from "../types/public";
 import { MissingSandboxApiUrlError } from "../utils/errors";
 
 type BasicInfo = { id: string; name: string };
@@ -26,22 +27,30 @@ export type UseSandboxProps = {
 
 export type RoomType = "conference" | "livestream" | "audio_only";
 
+export type SandboxOptions = {
+  videoCodec?: VideoCodec;
+};
+
 export const useSandbox = (props: UseSandboxProps) => {
   const sandboxApiUrl = props?.sandboxApiUrl;
 
   const getSandboxPeerToken = useCallback(
-    async (roomName: string, peerName: string, roomType: RoomType = "conference") => {
+    async (roomName: string, peerName: string, roomType: RoomType = "conference", options: SandboxOptions = {}) => {
       if (!sandboxApiUrl) throw new MissingSandboxApiUrlError();
 
       const url = new URL(sandboxApiUrl);
       url.searchParams.set("roomName", roomName);
       url.searchParams.set("peerName", peerName);
       url.searchParams.set("roomType", roomType);
+      if (options.videoCodec) url.searchParams.set("videoCodec", options.videoCodec);
 
       const res = await fetch(url);
 
       if (!res.ok) {
-        const message = `Failed to retrieve peer token for peer '${peerName}' in ${roomType} room '${roomName}'.`;
+        let message = `Failed to retrieve peer token for peer '${peerName}' in ${roomType} room '${roomName}'.`;
+        if (res.status === 409) {
+          message = `Room '${roomName}' already exists with a different room type or video codec.`;
+        }
         throw new Error(message);
       }
 
@@ -73,15 +82,22 @@ export const useSandbox = (props: UseSandboxProps) => {
   );
 
   const getSandboxLivestream = useCallback(
-    async (roomName: string, isPublic: boolean = false) => {
+    async (roomName: string, isPublic: boolean = false, options: SandboxOptions = {}) => {
       if (!sandboxApiUrl) throw new MissingSandboxApiUrlError();
 
       const url = new URL(`${sandboxApiUrl}/livestream`);
       url.searchParams.set("roomName", roomName);
       url.searchParams.set("public", isPublic.toString());
+      if (options.videoCodec) url.searchParams.set("videoCodec", options.videoCodec);
 
       const res = await fetch(url);
-      if (!res.ok) throw new Error(`Failed to retrieve streamer token for '${roomName}' livestream room.`);
+      if (!res.ok) {
+        let message = `Failed to retrieve streamer token for '${roomName}' livestream room.`;
+        if (res.status === 409) {
+          message = `Room '${roomName}' already exists with a different room type or video codec.`;
+        }
+        throw new Error(message);
+      }
 
       const data: { streamerToken: string; room: { id: string; name: string } } = await res.json();
       return data;
diff --git a/packages/react-client/src/index.ts b/packages/react-client/src/index.ts
index 5f404ec44..8d953a519 100644
--- a/packages/react-client/src/index.ts
+++ b/packages/react-client/src/index.ts
@@ -23,7 +23,13 @@ export {
   type UseLivestreamViewerResult,
 } from "./hooks/useLivestreamViewer";
 export { type PeerWithTracks, usePeers } from "./hooks/usePeers";
-export { type MoqAccess, type RoomType, useSandbox, type UseSandboxProps } from "./hooks/useSandbox";
+export {
+  type MoqAccess,
+  type RoomType,
+  type SandboxOptions,
+  useSandbox,
+  type UseSandboxProps,
+} from "./hooks/useSandbox";
 export { useScreenShare } from "./hooks/useScreenShare";
 export { useUpdatePeerMetadata } from "./hooks/useUpdatePeerMetadata";
 export { useVAD } from "./hooks/useVAD";
@@ -48,6 +54,7 @@ export type {
   TracksMiddleware,
   TracksMiddlewareResult,
   UseDataChannelResult,
+  VideoCodec,
 } from "./types/public";
 export type {
   AuthErrorReason,
diff --git a/packages/react-client/src/tests/sandbox.spec.ts b/packages/react-client/src/tests/sandbox.spec.ts
index 7b613a851..e8a3c61fd 100644
--- a/packages/react-client/src/tests/sandbox.spec.ts
+++ b/packages/react-client/src/tests/sandbox.spec.ts
@@ -41,6 +41,24 @@ describe("useSandbox", () => {
     expect(calledUrl.searchParams.get("roomType")).toBe("conference");
   });
 
+  it("getSandboxPeerToken passes the requested video codec", async ({ renderHook }) => {
+    const fetchSpy = mockFetch({ ok: true, json: async () => ({ peerToken: "pt" }) });
+    const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
+
+    await result.current.getSandboxPeerToken("room", "bob", "conference", { videoCodec: "h264" });
+    const calledUrl = new URL(fetchSpy.mock.calls[0][0]);
+    expect(calledUrl.searchParams.get("videoCodec")).toBe("h264");
+  });
+
+  it("getSandboxPeerToken omits the video codec by default", async ({ renderHook }) => {
+    const fetchSpy = mockFetch({ ok: true, json: async () => ({ peerToken: "pt" }) });
+    const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
+
+    await result.current.getSandboxPeerToken("room", "bob");
+    const calledUrl = new URL(fetchSpy.mock.calls[0][0]);
+    expect(calledUrl.searchParams.has("videoCodec")).toBe(false);
+  });
+
   it("getSandboxViewerToken gives a friendly error when the room is missing", async ({ renderHook }) => {
     mockFetch({ ok: false, status: 404 });
     const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
@@ -53,4 +71,47 @@ describe("useSandbox", () => {
     const data = await result.current.getSandboxLivestream("room", true);
     expect(data.streamerToken).toBe("st");
   });
+
+  it("getSandboxLivestream passes the visibility", async ({ renderHook }) => {
+    const fetchSpy = mockFetch({ ok: true, json: async () => ({ streamerToken: "st", room: { id: "r", name: "n" } }) });
+    const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
+
+    await result.current.getSandboxLivestream("room", true);
+    const calledUrl = new URL(fetchSpy.mock.calls[0][0]);
+    expect(calledUrl.searchParams.get("public")).toBe("true");
+  });
+
+  it("getSandboxLivestream passes the requested video codec", async ({ renderHook }) => {
+    const fetchSpy = mockFetch({ ok: true, json: async () => ({ streamerToken: "st", room: { id: "r", name: "n" } }) });
+    const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
+
+    await result.current.getSandboxLivestream("room", false, { videoCodec: "h264" });
+    const calledUrl = new URL(fetchSpy.mock.calls[0][0]);
+    expect(calledUrl.searchParams.get("videoCodec")).toBe("h264");
+  });
+
+  it("getSandboxLivestream omits the video codec by default", async ({ renderHook }) => {
+    const fetchSpy = mockFetch({ ok: true, json: async () => ({ streamerToken: "st", room: { id: "r", name: "n" } }) });
+    const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
+
+    await result.current.getSandboxLivestream("room");
+    const calledUrl = new URL(fetchSpy.mock.calls[0][0]);
+    expect(calledUrl.searchParams.has("videoCodec")).toBe(false);
+  });
+
+  it("getSandboxPeerToken explains a conflicting room configuration", async ({ renderHook }) => {
+    mockFetch({ ok: false, status: 409 });
+    const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
+    await expect(
+      result.current.getSandboxPeerToken("room", "bob", "conference", { videoCodec: "h264" }),
+    ).rejects.toThrow(/already exists with a different/);
+  });
+
+  it("getSandboxLivestream explains a conflicting room configuration", async ({ renderHook }) => {
+    mockFetch({ ok: false, status: 409 });
+    const { result } = renderHook(() => useSandbox({ sandboxApiUrl: "https://sandbox.test/api" }));
+    await expect(result.current.getSandboxLivestream("room", false, { videoCodec: "h264" })).rejects.toThrow(
+      /already exists with a different/,
+    );
+  });
 });
diff --git a/packages/react-client/src/types/public.ts b/packages/react-client/src/types/public.ts
index 576558475..5ba0690af 100644
--- a/packages/react-client/src/types/public.ts
+++ b/packages/react-client/src/types/public.ts
@@ -15,6 +15,8 @@ export type InitializeDevicesResult = {
   errors: { audio: DeviceError | null; video: DeviceError | null } | null;
 };
 
+export type VideoCodec = "vp8" | "h264";
+
 export type TrackId = Brand<string, "TrackId">;
 export type PeerId = Brand<string, "PeerId">;