OpenAI makes the GPT-Live outbound telephony API generally available
Justin Uberti, OpenAI's Head of Realtime AI, said the GPT-Live outbound telephony API is now generally available: voice agents can place calls through any SIP trunk provider such as Telnyx or Twilio, with HD Voice and keypad events. OpenAI's docs say it is available to all organizations.
Verified against a post on X by Justin Uberti, Head of Realtime AI at OpenAI (2026-11-05 06:01 Singapore time), a quote post by OpenAI President Greg Brockman, and OpenAI's Telephony and SIP documentation:
OpenAI has moved the GPT-Live outbound telephony API to general availability (GA). Developers can now have a voice agent built on GPT-Live place phone calls through any SIP trunk provider, such as Telnyx or Twilio. SIP is a protocol for making phone calls over the internet; a SIP trunk provider connects those calls to the regular phone network.
Uberti wrote that calls can use HD Voice and can send and receive keypad events (DTMF, the tones made by phone keys).
The documentation adds:
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Outbound SIP calling is available to all organizations through the Live API, not through the Realtime API call-creation endpoint.
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Developers start a call with
POST /v1/live/sessionsandtransport.type: "sip"; the trunk must support TLS signaling and SDES-SRTP media. -
The destination must be a phone number in E.164 format; SIP URI destinations aren't supported.
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Ringing is limited to 3 minutes and a connected call to 2 hours; these limits can't be changed in the request.
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Active calls can be transferred or hung up.