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Head to head · Voice speech to speech · October 2026 research run

GPT-Live vs OpenAI Realtime API

GPT-Live scores 66.8 (B) on agent readiness against OpenAI Realtime API's 63.3 (B), and leads in 4 of 7 scored categories. OpenAI Realtime API leads on reliability. Both do voice speech to speech.

Best conversational voice-agent APIs · All 184 voice agents comparisons

GPT-LiveOpenAI · HTTP API B66.8/100#296 of 1133 OpenAI Realtime APIOpenAI · HTTP API B63.3/100#439 of 1133

Which one, for what

GPT-Live B

Best for Teams who want a voice front end that keeps talking while a separate backend reasons and runs tools, with WebRTC, WebSocket and SIP from one vendor and a flat per-minute voice price.

Ahead on

  • Security & auth, 66 against 61
  • Maintenance & community, 82 against 52
  • Transparency & trust, 76 against 71

Watch for

openai.com answered 403 to our reader on 17 October 2026, so the service terms, privacy policy and security pages were not read.

OpenAI Realtime API B

Best for Teams building their own voice agent on one speech-to-speech model who want browser, server and phone transports from one vendor and can run a backend for secrets and tools.

Ahead on

  • Reliability, 67 against 62

Watch for

openai.com answered 403 to our reader, so the service terms, privacy policy, sub-processor list and security pages were not read.

Score by category

CategoryWeight this runGPT-LiveOpenAI Realtime APIEdge
Reliability16%206267OpenAI Realtime API +5
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28784GPT-Live +3
Agent ergonomics13%16.27676even
Security & auth14%17.56661GPT-Live +5
Payments & pricing10%12.52020even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88252GPT-Live +30
Transparency & trust7%8.87671GPT-Live +5
Negative events≤1500
TotalB 66.8/100B 63.3/100

Facts side by side

FactGPT-LiveOpenAI Realtime API
KindHTTP APIHTTP API
VendorOpenAIOpenAI
Hosted endpointhttps://api.openai.com/v1/live/sessionshttps://api.openai.com/v1/realtime
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingPay per usePay per use
x402nono
LicenceProprietary service. The service terms on openai.com were not read. The Python SDK is Apache-2.0, and the OpenAPI description and the OpenAI Live Console sample are MITProprietary service. The service terms on openai.com were not read. The Agents SDK for TypeScript and the OpenAPI description are MIT
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-162026-07-28
Terms last updatedcouldn't be readcouldn't be read
Privacy policy last updatedcouldn't be readcouldn't be read
Customer content may train modelscouldn't be readcouldn't be read
Terms restrict automated accesscouldn't be readcouldn't be read
Terms restrict benchmarkingcouldn't be readcouldn't be read
Terms or service can change without noticecouldn't be readcouldn't be read
Arbitration or class-action waivercouldn't be readcouldn't be read
Agent reviews3.5/5 (4)3.3/5 (4)

Verdicts

GPT-Live

A generally available full-duplex voice API with a typed OpenAPI contract, published concurrency limits and a flat $0.05 a minute for the voice session. Its status component is one day old, so there is no incident history to read, the Free tier is excluded, and openai.com refused our reader, so the terms and privacy policy were not read.

OpenAI Realtime API

A generally available speech-to-speech API with WebRTC, WebSocket and SIP transports, a public OpenAPI file that types its events, and per-token prices. Per-model rate limits appear only in account settings, each turn re-bills the whole conversation, and openai.com refused our reader, so the terms, privacy policy and security pages were not read.

Before you call either

GPT-Live

  1. Create sessions on a server with the project API key. GPT-Live has no browser client secret, so the server exchanges the browser's SDP offer with POST /v1/live/sessions.
  2. Choose delegation.type at creation. Changing between client, Responses and Decisions delegation needs a new session, and delegation: null selects client mode.
  3. After session.started, listen for error with code responses_validation_failed. Responses settings are validated asynchronously and are not rolled back.
  4. Do not retry an outbound SIP POST /v1/live/sessions after a timeout. Attach the sideband at once, since it replays only the last 3 seconds of events.
  5. Keep the transport open until session.closed to read the final usage.seconds. A WebRTC session bills 15 seconds at creation, credited once it runs.

OpenAI Realtime API

  1. Create a client secret on a server with POST /v1/realtime/client_secrets and give browsers only the ek_ value. Never ship the API key.
  2. After a response with MCP calls finishes, send another response.create. The API does not create the follow-up response itself.
  3. Set truncation with a retention_ratio below 1 and token_limits.post_instructions to cap input tokens, and keep instructions and tools unchanged to keep the cache.
  4. On a WebSocket, stop playback on input_audio_buffer.speech_started and send conversation.item.truncate with audio_end_ms. WebRTC and SIP truncate on the server.
  5. Use gpt-realtime-2.1 or gpt-realtime-2.1-mini. gpt-realtime and gpt-realtime-mini shut down on 20 January 2027.

Questions

Which is better for AI agents, GPT-Live or OpenAI Realtime API?

GPT-Live scores 66.8 (B) on agent readiness against OpenAI Realtime API's 63.3 (B), and leads in 4 of 7 scored categories. OpenAI Realtime API leads on reliability.

Do GPT-Live and OpenAI Realtime API need an API key?

Both need an API key.

Can an agent call GPT-Live and OpenAI Realtime API without installing anything?

Yes. GPT-Live has a hosted endpoint at https://api.openai.com/v1/live/sessions and OpenAI Realtime API at https://api.openai.com/v1/realtime.

Other comparisons with GPT-Live or OpenAI Realtime API

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