T9-R4 in five minutes

The W3C WebRTC Recommendation of 13 March 2025 defines APIs so media can be sent to and received from another browser or device.

Wikipedia's WebRTC page says the API does not include signaling, and that an application may use SIP or another protocol.

RFC 3261 defines SIP, the Session Initiation Protocol.

The xAI Speech to Speech page says you can connect via SIP, WebSocket, or LiveKit, and names native G.711 μ-law and A-law support.

That page says PSTN, contact-center, or PBX calls can be routed into a session. This lab places no call.

WebRTC carries media. SIP is a signaling protocol. Put them in different boxes. Leave the API key off the page.

Sources and go deeper

W3C, WebRTC Recommendation, 13 March 2025 spec last checked 2026-10
WebRTC — Wikipedia wikipedia last checked 2026-10
RFC 3261, SIP: Session Initiation Protocol spec last checked 2026-10
Speech to Speech, docs.x.ai vendor The page title is Speech to Speech. The body names the Grok Speech to Speech API and also calls the site SpaceXSI Docs. last checked 2026-10