Add webRtc.iceTransportPolicy session option for WebRTC connections (#934)

* Add rtcConfig session option for WebRTC connections

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Use as const in rtcConfig test

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Replace rtcConfig with webRtc.iceTransportPolicy option

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: a1anfan

.changeset/rtc-config-passthrough.md

@@ -0,0 +1,5 @@
+---
+"@elevenlabs/client": minor
+---
+
+Add an optional `webRtc.iceTransportPolicy` session option for WebRTC connections. Set to `"relay"` to restrict ICE to TURN relay candidates, for networks that drop direct UDP flows, without patching the global `RTCPeerConnection`.

packages/client/src/utils/BaseConnection.ts

@@ -31,6 +31,14 @@ export type BaseSessionConfig = {
   origin?: string;
   authorization?: string;
   livekitUrl?: string;
+  webRtc?: {
+    /**
+     * ICE transport policy for the WebRTC connection. Set to "relay" to only
+     * use TURN relay candidates, e.g. on networks that drop direct UDP flows.
+     * Defaults to "all".
+     */
+    iceTransportPolicy?: "all" | "relay";
+  };
   overrides?: {
     agent?: {
       prompt?: ConversationConfigOverrideAgentPrompt;

packages/client/src/utils/WebRTCConnection.test.ts

@@ -133,6 +133,38 @@ describe("WebRTCConnection", () => {
     connection.close();
   });
 
+  it("passes webRtc.iceTransportPolicy through to room.connect", async () => {
+    const mockRoom = new Room() as any;
+    (mockRoom.on as ReturnType<typeof vi.fn>).mockImplementation(
+      (event: string, callback: () => void) => {
+        if (event === "connected") {
+          queueMicrotask(callback);
+        }
+      }
+    );
+    (mockRoom.once as ReturnType<typeof vi.fn>).mockImplementation(
+      (event: string, callback: () => void) => {
+        if (event === "signalConnected") {
+          queueMicrotask(callback);
+        }
+      }
+    );
+
+    const connection = await WebRTCConnection.create({
+      conversationToken: "test-token",
+      connectionType: "webrtc",
+      webRtc: { iceTransportPolicy: "relay" },
+    });
+
+    expect(mockRoom.connect).toHaveBeenCalledWith(
+      expect.any(String),
+      "test-token",
+      { rtcConfig: { iceTransportPolicy: "relay" } }
+    );
+
+    connection.close();
+  });
+
   it("reconnects input analyser after unmuting", async () => {
     const mockRoom = new Room() as any;
 

packages/client/src/utils/WebRTCConnection.ts

@@ -323,7 +323,10 @@ export class WebRTCConnection extends BaseConnection {
           });
 
       // Connect to the LiveKit room
-      await room.connect(livekitUrl, conversationToken);
+      const iceTransportPolicy = config.webRtc?.iceTransportPolicy;
+      await room.connect(livekitUrl, conversationToken, {
+        rtcConfig: iceTransportPolicy ? { iceTransportPolicy } : undefined,
+      });
 
       // Wait for the Connected event to ensure isConnected is true
       await new Promise<void>(resolve => {