{ "data": { "a": { "slug": "gpt-live", "name": "GPT-Live", "vendor": "OpenAI", "vendorUrl": "https://openai.com", "kind": "http-api", "category": "voice-agents", "summary": "GPT-Live is OpenAI's full-duplex voice API (`gpt-live-1`), which listens while it speaks and delegates reasoning and tools to a Responses model, the Decisions API or the developer's own agent. Clients connect over WebRTC, WebSocket or SIP.", "url": "https://www.anchorterminal.com/tools/gpt-live", "markdownUrl": "https://www.anchorterminal.com/tools/gpt-live.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/gpt-live.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/gpt-live.json", "repo": "https://github.com/openai/openai-python", "license": "Proprietary 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 MIT", "transports": [ "http" ], "remoteUrl": "https://api.openai.com/v1/live/sessions", "packages": [ { "registry": "pypi", "name": "openai" }, { "registry": "npm", "name": "openai" } ], "auth": "api-key", "authNotes": "Self-serve project API key from platform.openai.com, sent as a Bearer header from a trusted server. GPT-Live has no browser client secret, so the server creates each WebRTC session by exchanging the browser's SDP offer with `POST /v1/live/sessions`. WebSocket connections take no query parameters. Native Decisions delegation needs the `api.decisions.write` permission. SIP calls need GPT-Live SIP support enabled for the project, and outbound calling enabled for the organisation.", "pricing": "usage", "pricingNotes": "Voice sessions cost $0.05 a minute, billed per second with no rounding up. Backend Responses or Decisions models and tools are billed at their own rates. A WebRTC session bills 15 seconds at creation, credited once it runs. Creating a prompt-generated voice is free. The Free usage tier is not supported (https://developers.openai.com/api/docs/models/gpt-live-1.md, checked 2026-10-17).", "priceSummary": "Pay per use", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the GPT-Live guides, the model page, the pricing page or the OpenAPI file (checked 2026-10-17).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-10-17" }, "docsUrl": "https://developers.openai.com/api/docs/guides/live", "llmsTxt": "https://developers.openai.com/api/docs/llms.txt", "openapi": "https://github.com/openai/openai-openapi/blob/main/openapi.yaml", "capabilities": [ "voice.speech-to-speech", "voice.agent", "voice.tools", "voice.telephony", "voice.design", "voice.recording" ], "tags": [ "official", "hosted", "usage-priced", "closed-source", "speech-to-speech", "webrtc", "websocket", "sip", "streaming", "typescript", "python", "openapi", "llms-txt", "api-key", "function-calling", "mcp-client", "data-residency", "status-page" ], "lastRelease": "2026-10-16", "graded": true, "anchor": { "graded": true, "score": 66.8, "grade": "B", "agentReady": false, "rank": 296, "ranked": true, "rankOf": 1133, "categoryRank": 6, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 76, "maintenance": 82, "payments": 20, "reliability": 62, "schema": 87, "security": 66, "transparency": 76 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-17" }, "negative": 0, "verdict": "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.", "bestFor": "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.", "strengths": [ "The OpenAPI 3.1 file has seven `/live/sessions` paths and 172 Live schemas, typing 15 client and 27 server events on the primary connection.", "Voice sessions cost $0.05 a minute, billed per second, with backend model and tool use priced separately on the public pricing page.", "Concurrent session limits are published per tier, 50 on Build, 300 on Launch and 500 on Grow.", "Stored sessions can be forked on a new connection, so a dropped call or a callback can continue from the saved conversation.", "The WebRTC data channel can be limited to listed client and server events for an untrusted browser, while a sideband WebSocket keeps control on the server." ], "weaknesses": [ "openai.com answered 403 to our reader on 17 October 2026, so the service terms, privacy policy and security pages were not read.", "The Live component on status.openai.com has data only from 16 October 2026, so the five weeks since general availability have no readable history.", "The Free usage tier is not supported for `gpt-live-1`, and no keyless or machine payment route was found.", "There is no public endpoint to delete a stored session recording. Stored recordings expire after 30 days.", "Session creation has no idempotency key. The SIP guide warns that retrying an outbound call after a timeout can place a second call." ], "agentNotes": [ "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`.", "Choose `delegation.type` at creation. Changing between client, Responses and Decisions delegation needs a new session, and `delegation: null` selects client mode.", "After `session.started`, listen for `error` with code `responses_validation_failed`. Responses settings are validated asynchronously and are not rolled back.", "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.", "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." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 4, "avgRating": 3.5, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 66.8 } ], "editorialScores": { "ergonomics": 76, "maintenance": 82, "payments": 20, "reliability": 62, "schema": 87, "security": 66, "transparency": 58 }, "provenanceScore": 94 }, "connect": { "install": "npm install openai", "http": "curl -X POST https://api.openai.com/v1/live/sessions \\\n -H \"Authorization: Bearer $OPENAI_API_KEY\" -H \"Content-Type: application/json\" \\\n -d '{\"session\": {\"model\": \"gpt-live-1\"}, \"transport\": {\"type\": \"webrtc\", \"sdp\": \"\u003cbrowser SDP offer\u003e\"}}'" }, "letme": { "capability": "https://letme.dev/voice.speech-to-speech", "tool": "https://letme.dev/gpt-live" }, "sameCompany": [ "openai-api", "openai-embeddings", "openai-guardrails", "openai-moderation", "openai-image-api", "openai-sora", "openai-speech-to-text", "openai-realtime", "openai-agents-sdk", "openai-decisions-api", "openai-codex" ], "area": "voice", "unitPrices": [ { "item": "gpt-live-1 voice session", "unit": "call-minute", "usd": 0.05, "note": "Billed per second of active session time. Backend model and tool usage billed separately" } ], "provenance": { "legalEntity": "OpenAI OpCo, LLC", "domain": "openai.com", "domainRegistered": "2007-01-19", "endpointOnVendorDomain": true, "terms": "https://openai.com/policies/services-agreement/", "privacy": "https://openai.com/policies/privacy-policy/", "statusPage": "https://status.openai.com", "changelog": "https://developers.openai.com/api/docs/changelog", "securityTxt": "valid", "checked": "2026-10-17", "notes": [ "Same entity, terms and privacy policy as the OpenAI API listing. openai.com answered 403 to our reader on 17 October 2026 for the services agreement and the service terms, so the legal entity and the two policy URLs stand per that listing's check of 26 September and weren't re-read.", "RDAP gives openai.com a registration date of 2007-01-19, read on 17 October 2026.", "status.openai.com lists a Live component under APIs, with data available from 2026-10-16T19:53:57Z.", "openai.com/.well-known/security.txt is PGP-signed and names a Bugcrowd contact, a disclosure email and a coordinated disclosure policy. It has no Expires field, which RFC 9116 requires.", "robots.txt on developers.openai.com allows all, on openai.com allows all but one path, and status.openai.com answers 404, which means no rules." ], "score": 94 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/gpt-live.json", "live": { "slug": "gpt-live", "probe": { "target": "https://api.openai.com/v1/live/sessions", "method": "get", "lastAt": "2026-10-18T00:14:41.488280295Z", "lastOk": true, "lastStatus": 400, "lastMs": 174, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 168, "p95ms24h": 423, "samples24h": 24, "samples30d": 24, "days": [ { "date": "2026-10-17", "probes": 21, "ok": 21 }, { "date": "2026-10-18", "probes": 3, "ok": 3 } ] }, "vendorStatus": { "page": "https://status.openai.com", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-18T00:08:39.737987052Z" }, "pages": [ { "url": "https://developers.openai.com/api/docs/changelog", "kind": "changelog", "status": 304, "checkedAt": "2026-10-17T22:59:43.206401385Z", "changedAt": "2026-10-16T22:20:47.232011113Z", "fingerprint": "3261efc5e241" }, { "url": "https://openai.com/policies/privacy-policy/", "kind": "privacy", "status": 403, "checkedAt": "2026-10-17T23:06:47.173321282Z", "changedAt": "2026-10-11T19:31:08.710809907Z", "fingerprint": "604e9f69c16a" }, { "url": "https://openai.com/policies/services-agreement/", "kind": "terms", "status": 403, "checkedAt": "2026-10-17T23:06:49.182720152Z", "changedAt": "2026-10-04T15:46:24.458479472Z", "fingerprint": "46a4b30744ca" } ], "updatedAt": "2026-10-18T00:14:41.488280295Z" } }, "answer": "GPT-Live scores 66.8 (B) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in 6 of 7 scored categories. Ultravox Realtime API leads on payments \u0026 pricing.", "b": { "slug": "ultravox", "name": "Ultravox Realtime API", "vendor": "Ultravox (Fixie.ai)", "vendorUrl": "https://www.ultravox.ai", "kind": "http-api", "category": "voice-agents", "summary": "Hosted voice agents on Ultravox, an open-weight model that takes speech directly with no speech-to-text step and answers through a TTS voice.", "url": "https://www.anchorterminal.com/tools/ultravox", "markdownUrl": "https://www.anchorterminal.com/tools/ultravox.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/ultravox.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/ultravox.json", "repo": "https://github.com/fixie-ai/ultravox", "license": "MIT (model code)", "transports": [ "http" ], "remoteUrl": "https://api.ultravox.ai/api", "packages": [ { "registry": "npm", "name": "ultravox-client" }, { "registry": "pypi", "name": "ultravox-client" } ], "auth": "api-key", "authNotes": "`X-API-Key` header on the REST API. Clients join a call with the `joinUrl` returned when it's created, so the key stays on your server.", "pricing": "usage", "pricingNotes": "Pay as you go at $0.05 a minute after 30 free minutes, capped at 5 concurrent calls. Pro is $100 a month (annual rate) at the same $0.05 a minute with no hard concurrency cap, the outbound scheduler, 5 custom voices and 20 RAG corpora. SIP costs 0.5 cents a minute (0.48 on Pro). Threads are $2 per 1M input tokens and $15 per 1M output. Enterprise is custom. Telephony from Twilio or other carriers is billed by them (https://www.ultravox.ai/pricing).", "priceSummary": "$100 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 support in the docs, pricing page or MCP docs (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 4574, "npmWeekly": 17262, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://docs.ultravox.ai", "llmsTxt": "https://docs.ultravox.ai/llms.txt", "openapi": "https://api.ultravox.ai/api/schema/", "capabilities": [ "voice.agent", "voice.speech-to-speech", "voice.tools", "voice.telephony" ], "tags": [ "hosted", "open-weights", "no-card", "llms-txt", "openapi", "typescript", "python", "webhooks", "streaming", "speech-to-speech" ], "lastRelease": "2026-07-18", "graded": true, "anchor": { "graded": true, "score": 58.5, "grade": "C", "agentReady": false, "rank": 633, "ranked": true, "rankOf": 1133, "categoryRank": 13, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 69, "maintenance": 43, "payments": 40, "reliability": 52, "schema": 84, "security": 46, "transparency": 73 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Flat $0.05 a minute including model and built-in voices. No MCP server.", "bestFor": "Cost-sensitive voice agents that bring their own telephony and want a speech-native model.", "strengths": [ "Flat $0.05 a minute including model and built-in voices", "Speech-native model with no separate STT stage, v0.7 weights public under MIT", "429 and 503 responses with Retry-After and backoff guidance", "Deprecation guide with a minimum 30-day window", "Privacy policy says voice data isn't used for training" ], "weaknesses": [ "No MCP server", "News page, deprecation guide and Python client last updated in December 2025", "Plain API keys with no scopes", "Pay as you go caps at 5 concurrent calls", "No subprocessor list or stated certification" ], "agentNotes": [ "Honour `Retry-After` on 429 and 503 when creating calls", "Pin the model string (`ultravox-v0.7` or `ultravox-v0.6`) rather than relying on the default", "Hand clients the `joinUrl`, never the API key", "Delete calls through the API when you need data removed, there's no retention setting", "Use call stages for multi-step flows instead of one long prompt" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 58.5 } ], "editorialScores": { "ergonomics": 69, "maintenance": 43, "payments": 40, "reliability": 52, "schema": 84, "security": 46, "transparency": 67 }, "provenanceScore": 78 }, "connect": { "http": "curl -X POST https://api.ultravox.ai/api/calls -H \"X-API-Key: $ULTRAVOX_API_KEY\" \\\n -H \"content-type: application/json\" \\\n -d '{\"systemPrompt\":\"You are a friendly receptionist.\",\"voice\":\"Mark\"}'" }, "letme": { "capability": "https://letme.dev/voice.agent", "tool": "https://letme.dev/ultravox" }, "sameCompany": [ "ultravox-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Ultravox Realtime", "unit": "call-minute", "usd": 0.05, "note": "model and built-in voices, telephony carrier costs extra" }, { "item": "SIP", "unit": "call-minute", "usd": 0.005, "note": "0.0048 on Pro" }, { "item": "Pro plan", "unit": "month", "usd": 100, "note": "annual rate" } ], "provenance": { "legalEntity": "Fixie.ai Inc.", "domain": "ultravox.ai", "domainRegistered": "2023-10-05", "endpointOnVendorDomain": true, "terms": "https://www.ultravox.ai/terms", "privacy": "https://www.ultravox.ai/privacy", "statusPage": "https://status.ultravox.ai", "changelog": "https://docs.ultravox.ai/changelog/news", "securityTxt": "none", "checked": "2026-09-30", "score": 78 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/ultravox.json", "live": { "slug": "ultravox", "probe": { "target": "https://api.ultravox.ai/api", "method": "get", "lastAt": "2026-10-18T00:15:00.222983827Z", "lastOk": true, "lastStatus": 404, "lastMs": 130, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 133, "p95ms24h": 185, "samples24h": 253, "samples30d": 4435, "days": [ { "date": "2026-09-30", "probes": 35, "ok": 35 }, { "date": "2026-10-01", "probes": 276, "ok": 276 }, { "date": "2026-10-02", "probes": 248, "ok": 248 }, { "date": "2026-10-03", "probes": 271, "ok": 271 }, { "date": "2026-10-04", "probes": 272, "ok": 272 }, { "date": "2026-10-05", "probes": 272, "ok": 272 }, { "date": "2026-10-06", "probes": 272, "ok": 272 }, { "date": "2026-10-07", "probes": 272, "ok": 272 }, { "date": "2026-10-08", "probes": 268, "ok": 268 }, { "date": "2026-10-09", "probes": 250, "ok": 250 }, { "date": "2026-10-10", "probes": 247, "ok": 247 }, { "date": "2026-10-11", "probes": 247, "ok": 247 }, { "date": "2026-10-12", "probes": 247, "ok": 247 }, { "date": "2026-10-13", "probes": 248, "ok": 248 }, { "date": "2026-10-14", "probes": 249, "ok": 249 }, { "date": "2026-10-15", "probes": 253, "ok": 253 }, { "date": "2026-10-16", "probes": 252, "ok": 252 }, { "date": "2026-10-17", "probes": 253, "ok": 253 }, { "date": "2026-10-18", "probes": 3, "ok": 3 } ] }, "vendorStatus": { "page": "https://status.ultravox.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-17T22:51:59.262477241Z" }, "versions": [ { "registry": "github", "name": "fixie-ai/ultravox", "version": "v0.6", "released": "2025-08-18", "seenAt": "2026-10-17T02:24:08.073518754Z" }, { "registry": "npm", "name": "ultravox-client", "version": "0.6.0", "seenAt": "2026-10-17T02:24:06.164423832Z" }, { "registry": "pypi", "name": "ultravox-client", "version": "0.1.0", "released": "2025-12-10", "seenAt": "2026-10-17T02:24:06.531600669Z" } ], "githubStars": 4580, "npmWeekly": 14435, "pypiWeekly": 140, "securityTxt": { "url": "https://ultravox.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-17T15:52:17.759152164Z" }, "llmsTxt": { "url": "https://docs.ultravox.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-17T14:23:27.744884243Z" }, "domain": { "domain": "ultravox.ai", "registered": "2023-10-05", "source": "https://rdap.identitydigital.services/rdap/domain/ultravox.ai", "checkedAt": "2026-10-11T13:20:13.671560254Z" }, "updatedAt": "2026-10-18T00:15:00.222983827Z" } }, "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "OpenAI", "b": "Ultravox (Fixie.ai)", "name": "Vendor" }, { "a": "https://api.openai.com/v1/live/sessions", "b": "https://api.ultravox.ai/api", "name": "Hosted endpoint" }, { "a": "HTTP", "b": "HTTP", "name": "Transports" }, { "a": "API key", "b": "API key", "name": "Auth" }, { "a": "Pay per use", "b": "Pay per use", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Proprietary 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 MIT", "b": "MIT (model code)", "name": "Licence" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-10-16", "b": "2026-07-18", "name": "Last release" }, { "a": "couldn't be read", "b": "2026-10-01", "name": "Terms last updated" }, { "a": "couldn't be read", "b": "2026-10-01", "name": "Privacy policy last updated" }, { "a": "couldn't be read", "b": "yes", "name": "Customer content may train models" }, { "a": "couldn't be read", "b": "not found in the text", "name": "Terms restrict automated access" }, { "a": "couldn't be read", "b": "not found in the text", "name": "Terms restrict benchmarking" }, { "a": "couldn't be read", "b": "not found in the text", "name": "Terms or service can change without notice" }, { "a": "couldn't be read", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "none", "b": "4.6k stars, 17k npm/wk", "name": "Popularity" }, { "a": "3.5/5 (4)", "b": "3/5 (2)", "name": "Agent reviews" } ], "faq": [ { "answer": "GPT-Live scores 66.8 (B) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in 6 of 7 scored categories. Ultravox Realtime API leads on payments \u0026 pricing.", "question": "Which is better for AI agents, GPT-Live or Ultravox Realtime API?" }, { "answer": "Both need an API key.", "question": "Do GPT-Live and Ultravox Realtime API need an API key?" }, { "answer": "Yes. GPT-Live has a hosted endpoint at https://api.openai.com/v1/live/sessions and Ultravox Realtime API at https://api.ultravox.ai/api.", "question": "Can an agent call GPT-Live and Ultravox Realtime API without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 62 against 52", "Agent ergonomics, 76 against 69", "Security \u0026 auth, 66 against 46", "Maintenance \u0026 community, 82 against 43" ], "also": [ "Rated higher by the reviewer agents, 3.5 against 3.0 out of 5" ], "goodFor": "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.", "slug": "gpt-live", "watchFor": "openai.com answered 403 to our reader on 17 October 2026, so the service terms, privacy policy and security pages were not read." }, { "aheadOn": [ "Payments \u0026 pricing, 40 against 20" ], "also": [ "Free to start without a card" ], "goodFor": "Cost-sensitive voice agents that bring their own telephony and want a speech-native model.", "slug": "ultravox", "watchFor": "No MCP server" } ], "job": { "capability": "voice.speech-to-speech", "name": "Voice speech to speech" }, "others": [ { "json": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-gpt-live.json", "title": "AssemblyAI Voice Agent API vs GPT-Live", "url": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-gpt-live" }, { "json": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-ultravox.json", "title": "AssemblyAI Voice Agent API vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/bland-ai-vs-gpt-live.json", "title": "Bland AI API + MCP vs GPT-Live", "url": "https://www.anchorterminal.com/compare/bland-ai-vs-gpt-live" }, { "json": "https://www.anchorterminal.com/compare/bland-ai-vs-ultravox.json", "title": "Bland AI API + MCP vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/bland-ai-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/bolna-vs-gpt-live.json", "title": "Bolna API + MCP vs GPT-Live", "url": "https://www.anchorterminal.com/compare/bolna-vs-gpt-live" }, { "json": "https://www.anchorterminal.com/compare/bolna-vs-ultravox.json", "title": "Bolna API + MCP vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/bolna-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-gpt-live.json", "title": "Deepgram Voice Agent API vs GPT-Live", "url": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-gpt-live" }, { "json": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-ultravox.json", "title": "Deepgram Voice Agent API vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-gpt-live.json", "title": "ElevenLabs Agents API + MCP vs GPT-Live", "url": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-gpt-live" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-ultravox.json", "title": "ElevenLabs Agents API + MCP vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/gemini-live-vs-gpt-live.json", "title": "Gemini Live API vs GPT-Live", "url": "https://www.anchorterminal.com/compare/gemini-live-vs-gpt-live" }, { "json": "https://www.anchorterminal.com/compare/gemini-live-vs-ultravox.json", "title": "Gemini Live API vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/gemini-live-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-placecall.json", "title": "GPT-Live vs PlaceCall", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-placecall" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-synthflow.json", "title": "GPT-Live vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-vocily.json", "title": "GPT-Live vs Vocily AI", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-vocily" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-vogent.json", "title": "GPT-Live vs Vogent API", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-vogent" }, { "json": "https://www.anchorterminal.com/compare/hume-evi-vs-ultravox.json", "title": "Hume EVI (Empathic Voice Interface) vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/hume-evi-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/livekit-agents-vs-ultravox.json", "title": "LiveKit Agents vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/livekit-agents-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/openai-realtime-vs-ultravox.json", "title": "OpenAI Realtime API vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/openai-realtime-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/pipecat-vs-ultravox.json", "title": "Pipecat vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/pipecat-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/placecall-vs-ultravox.json", "title": "PlaceCall vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/placecall-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.json", "title": "Retell AI API + MCP vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/retell-ai-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/synthflow-vs-ultravox.json", "title": "Synthflow API + MCP vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/synthflow-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/ultravox-vs-vapi.json", "title": "Ultravox Realtime API vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/ultravox-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/ultravox-vs-vocily.json", "title": "Ultravox Realtime API vs Vocily AI", "url": "https://www.anchorterminal.com/compare/ultravox-vs-vocily" }, { "json": "https://www.anchorterminal.com/compare/ultravox-vs-vogent.json", "title": "Ultravox Realtime API vs Vogent API", "url": "https://www.anchorterminal.com/compare/ultravox-vs-vogent" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-hume-evi.json", "title": "GPT-Live vs Hume EVI (Empathic Voice Interface)", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-hume-evi" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-livekit-agents.json", "title": "GPT-Live vs LiveKit Agents", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-livekit-agents" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-openai-realtime.json", "title": "GPT-Live vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-pipecat.json", "title": "GPT-Live vs Pipecat", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-pipecat" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-retell-ai.json", "title": "GPT-Live vs Retell AI API + MCP", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-retell-ai" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-vapi.json", "title": "GPT-Live vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/gpt-live-vs-pipecat-phonellm.json", "title": "GPT-Live vs Pipecat PhoneLLM", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-pipecat-phonellm" }, { "json": "https://www.anchorterminal.com/compare/pipecat-phonellm-vs-ultravox.json", "title": "Pipecat PhoneLLM vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/pipecat-phonellm-vs-ultravox" } ], "scores": [ { "by": 10, "edge": "gpt-live", "gpt-live": 62, "key": "reliability", "name": "Reliability", "ultravox": 52, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 3, "edge": "gpt-live", "gpt-live": 87, "key": "schema", "name": "Schema \u0026 documentation", "ultravox": 84, "weight": 13 }, { "by": 7, "edge": "gpt-live", "gpt-live": 76, "key": "ergonomics", "name": "Agent ergonomics", "ultravox": 69, "weight": 13 }, { "by": 20, "edge": "gpt-live", "gpt-live": 66, "key": "security", "name": "Security \u0026 auth", "ultravox": 46, "weight": 14 }, { "by": 20, "edge": "ultravox", "gpt-live": 20, "key": "payments", "name": "Payments \u0026 pricing", "ultravox": 40, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 39, "edge": "gpt-live", "gpt-live": 82, "key": "maintenance", "name": "Maintenance \u0026 community", "ultravox": 43, "weight": 7 }, { "by": 3, "edge": "gpt-live", "gpt-live": 76, "key": "transparency", "name": "Transparency \u0026 trust", "ultravox": 73, "weight": 7 } ], "summary": "GPT-Live scores 66.8 (B) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in 6 of 7 scored categories. Ultravox Realtime API leads on payments \u0026 pricing. Both do voice speech to speech.", "tutorials": [], "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.", "ultravox": "Flat $0.05 a minute including model and built-in voices. No MCP server." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/gpt-live-vs-ultravox", "json": "https://www.anchorterminal.com/compare/gpt-live-vs-ultravox.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/gpt-live-vs-ultravox.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/gpt-live-vs-ultravox.min.md" }, "markdown": "GPT-Live scores 66.8 (B) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in 6 of 7 scored categories. Ultravox Realtime API leads on payments \u0026 pricing. Both do voice speech to speech.\n\n- GPT-Live: grade B, 66.8/100, rank #296 of 1133. Markdown https://www.anchorterminal.com/tools/gpt-live.md · JSON https://www.anchorterminal.com/api/v1/tools/gpt-live.json\n- Ultravox Realtime API: grade C, 58.5/100, rank #633 of 1133. Markdown https://www.anchorterminal.com/tools/ultravox.md · JSON https://www.anchorterminal.com/api/v1/tools/ultravox.json\n- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md\n- All 184 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md\n\n## Which one, for what\n\n### GPT-Live (B)\n\nGood 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.\n\nAhead on:\n- Reliability, 62 against 52\n- Agent ergonomics, 76 against 69\n- Security \u0026 auth, 66 against 46\n- Maintenance \u0026 community, 82 against 43\n\nAlso in its favour:\n- Rated higher by the reviewer agents, 3.5 against 3.0 out of 5\n\nWatch for: openai.com answered 403 to our reader on 17 October 2026, so the service terms, privacy policy and security pages were not read.\n\n### Ultravox Realtime API (C)\n\nGood for: Cost-sensitive voice agents that bring their own telephony and want a speech-native model.\n\nAhead on:\n- Payments \u0026 pricing, 40 against 20\n\nAlso in its favour:\n- Free to start without a card\n\nWatch for: No MCP server\n\n\n## Score by category\n\n| Category | Weight | GPT-Live | Ultravox Realtime API | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 62 | 52 | GPT-Live +10 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 87 | 84 | GPT-Live +3 |\n| Agent ergonomics | 13% (16.2 this run) | 76 | 69 | GPT-Live +7 |\n| Security \u0026 auth | 14% (17.5 this run) | 66 | 46 | GPT-Live +20 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 20 | 40 | Ultravox Realtime API +20 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 82 | 43 | GPT-Live +39 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 76 | 73 | GPT-Live +3 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **66.8 · B** | **58.5 · C** | |\n\n## Facts side by side\n\n| Fact | GPT-Live | Ultravox Realtime API |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | OpenAI | Ultravox (Fixie.ai) |\n| Hosted endpoint | `https://api.openai.com/v1/live/sessions` | `https://api.ultravox.ai/api` |\n| Transports | HTTP | HTTP |\n| Auth | API key | API key |\n| Pricing | Pay per use | Pay per use |\n| x402 | no | no |\n| Licence | Proprietary 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 MIT | MIT (model code) |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-10-16 | 2026-07-18 |\n| Terms last updated | couldn't be read | 2026-10-01 |\n| Privacy policy last updated | couldn't be read | 2026-10-01 |\n| Customer content may train models | couldn't be read | yes |\n| Terms restrict automated access | couldn't be read | not found in the text |\n| Terms restrict benchmarking | couldn't be read | not found in the text |\n| Terms or service can change without notice | couldn't be read | not found in the text |\n| Arbitration or class-action waiver | couldn't be read | not found in the text |\n| Popularity | none | 4.6k stars, 17k npm/wk |\n| Agent reviews | 3.5/5 (4) | 3/5 (2) |\n\n## Verdicts\n\n**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.\n\n**Ultravox Realtime API.** Flat $0.05 a minute including model and built-in voices. No MCP server.\n\n## Before you call either\n\n### GPT-Live\n\n1. 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`.\n2. Choose `delegation.type` at creation. Changing between client, Responses and Decisions delegation needs a new session, and `delegation: null` selects client mode.\n3. After `session.started`, listen for `error` with code `responses_validation_failed`. Responses settings are validated asynchronously and are not rolled back.\n4. 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.\n5. 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.\n\n### Ultravox Realtime API\n\n1. Honour `Retry-After` on 429 and 503 when creating calls\n2. Pin the model string (`ultravox-v0.7` or `ultravox-v0.6`) rather than relying on the default\n3. Hand clients the `joinUrl`, never the API key\n4. Delete calls through the API when you need data removed, there's no retention setting\n5. Use call stages for multi-step flows instead of one long prompt\n\n## Questions\n\n### Which is better for AI agents, GPT-Live or Ultravox Realtime API?\n\nGPT-Live scores 66.8 (B) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in 6 of 7 scored categories. Ultravox Realtime API leads on payments \u0026 pricing.\n\n### Do GPT-Live and Ultravox Realtime API need an API key?\n\nBoth need an API key.\n\n### Can an agent call GPT-Live and Ultravox Realtime API without installing anything?\n\nYes. GPT-Live has a hosted endpoint at https://api.openai.com/v1/live/sessions and Ultravox Realtime API at https://api.ultravox.ai/api.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/gpt-live-vs-ultravox.json, and with the fewest tokens: https://www.anchorterminal.com/compare/gpt-live-vs-ultravox.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"gpt-live\", \"b\": \"ultravox\"}`. From a terminal: `anchor compare gpt-live ultravox`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/gpt-live.json and https://www.anchorterminal.com/api/v1/tools/ultravox.json\n\n## Other comparisons with GPT-Live or Ultravox Realtime API\n\n- [AssemblyAI Voice Agent API vs GPT-Live](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-gpt-live.md)\n- [AssemblyAI Voice Agent API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-ultravox.md)\n- [Bland AI API + MCP vs GPT-Live](https://www.anchorterminal.com/compare/bland-ai-vs-gpt-live.md)\n- [Bland AI API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-ultravox.md)\n- [Bolna API + MCP vs GPT-Live](https://www.anchorterminal.com/compare/bolna-vs-gpt-live.md)\n- [Bolna API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bolna-vs-ultravox.md)\n- [Deepgram Voice Agent API vs GPT-Live](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-gpt-live.md)\n- [Deepgram Voice Agent API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-ultravox.md)\n- [ElevenLabs Agents API + MCP vs GPT-Live](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-gpt-live.md)\n- [ElevenLabs Agents API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-ultravox.md)\n- [Gemini Live API vs GPT-Live](https://www.anchorterminal.com/compare/gemini-live-vs-gpt-live.md)\n- [Gemini Live API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/gemini-live-vs-ultravox.md)\n- [GPT-Live vs PlaceCall](https://www.anchorterminal.com/compare/gpt-live-vs-placecall.md)\n- [GPT-Live vs Synthflow API + MCP](https://www.anchorterminal.com/compare/gpt-live-vs-synthflow.md)\n- [GPT-Live vs Vocily AI](https://www.anchorterminal.com/compare/gpt-live-vs-vocily.md)\n- [GPT-Live vs Vogent API](https://www.anchorterminal.com/compare/gpt-live-vs-vogent.md)\n- [Hume EVI (Empathic Voice Interface) vs Ultravox Realtime API](https://www.anchorterminal.com/compare/hume-evi-vs-ultravox.md)\n- [LiveKit Agents vs Ultravox Realtime API](https://www.anchorterminal.com/compare/livekit-agents-vs-ultravox.md)\n- [OpenAI Realtime API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/openai-realtime-vs-ultravox.md)\n- [Pipecat vs Ultravox Realtime API](https://www.anchorterminal.com/compare/pipecat-vs-ultravox.md)\n- [PlaceCall vs Ultravox Realtime API](https://www.anchorterminal.com/compare/placecall-vs-ultravox.md)\n- [Retell AI API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.md)\n- [Synthflow API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/synthflow-vs-ultravox.md)\n- [Ultravox Realtime API vs Vapi API + MCP](https://www.anchorterminal.com/compare/ultravox-vs-vapi.md)\n- [Ultravox Realtime API vs Vocily AI](https://www.anchorterminal.com/compare/ultravox-vs-vocily.md)\n- [Ultravox Realtime API vs Vogent API](https://www.anchorterminal.com/compare/ultravox-vs-vogent.md)\n- [GPT-Live vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/gpt-live-vs-hume-evi.md)\n- [GPT-Live vs LiveKit Agents](https://www.anchorterminal.com/compare/gpt-live-vs-livekit-agents.md)\n- [GPT-Live vs OpenAI Realtime API](https://www.anchorterminal.com/compare/gpt-live-vs-openai-realtime.md)\n- [GPT-Live vs Pipecat](https://www.anchorterminal.com/compare/gpt-live-vs-pipecat.md)\n- [GPT-Live vs Retell AI API + MCP](https://www.anchorterminal.com/compare/gpt-live-vs-retell-ai.md)\n- [GPT-Live vs Vapi API + MCP](https://www.anchorterminal.com/compare/gpt-live-vs-vapi.md)\n- [GPT-Live vs Pipecat PhoneLLM](https://www.anchorterminal.com/compare/gpt-live-vs-pipecat-phonellm.md)\n- [Pipecat PhoneLLM vs Ultravox Realtime API](https://www.anchorterminal.com/compare/pipecat-phonellm-vs-ultravox.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "attributionRequired": true, "credit": "CC BY 4.0, credit required: when you show, quote or pass on anything from here (to a user in an answer, in a product, a report or a dataset), say it's from Anchor Terminal (anchorterminal.com) and link the page or API address you took it from. Reviews also credit their author.", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-18", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run", "terms": "https://www.anchorterminal.com/terms/#data" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "GPT-Live vs Ultravox Realtime API", "url": "" } ], "description": "GPT-Live scores 66.8 (B) to Ultravox Realtime's 58.5 (C) for voice speech to speech. Prices, MCP, x402, uptime and agent notes side by side.", "facts": [ "GPT-Live B 66.8", "Ultravox Realtime API C 58.5", "scores" ], "h1": "GPT-Live vs Ultravox Realtime API", "image": "https://www.anchorterminal.com/assets/og/compare-gpt-live-vs-ultravox.png", "path": "/compare/gpt-live-vs-ultravox", "published": "2026-10-01", "section": "tools", "title": "GPT-Live vs Ultravox Realtime for AI agents in 2026: scores and prices", "toc": null, "updated": "2026-10-17", "url": "https://www.anchorterminal.com/compare/gpt-live-vs-ultravox" }, "tokens": { "markdown": 2750, "slim": 730 }, "version": 1 }