{ "data": { "a": { "slug": "openai-realtime", "name": "OpenAI Realtime API", "vendor": "OpenAI", "vendorUrl": "https://openai.com", "kind": "http-api", "category": "voice-agents", "summary": "OpenAI's Realtime API runs spoken conversations with speech-to-speech models such as `gpt-realtime-2.1`. Clients connect over WebRTC, WebSocket or SIP, and sessions support interruptions, function calling and remote MCP tools.", "url": "https://www.anchorterminal.com/tools/openai-realtime", "markdownUrl": "https://www.anchorterminal.com/tools/openai-realtime.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/openai-realtime.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/openai-realtime.json", "repo": "https://github.com/openai/openai-agents-js", "license": "Proprietary service. The service terms on openai.com were not read. The Agents SDK for TypeScript and the OpenAPI description are MIT", "transports": [ "http" ], "remoteUrl": "https://api.openai.com/v1/realtime", "packages": [ { "registry": "npm", "name": "@openai/agents" }, { "registry": "npm", "name": "@openai/agents-realtime" } ], "auth": "api-key", "authNotes": "Self-serve API key from platform.openai.com, sent as a Bearer header on server WebSocket connections and call-control requests. For browsers and phones, a server calls `POST /v1/realtime/client_secrets` for a client secret (`ek_`) that lasts 10 seconds to 2 hours, 10 minutes by default, and can start several sessions until it expires. The browser WebSocket example passes the secret as a subprotocol. SIP calls are tied to a project by the project ID in the SIP address.", "pricing": "usage", "pricingNotes": "Per 1M tokens on `gpt-realtime-2.1`. Audio $32.00 in, $0.40 cached and $64.00 out, text $4.00 in and $24.00 out, image $5.00 in. `gpt-realtime-2.1-mini` is $10.00 and $20.00 for audio. Each response re-sends the whole conversation, and input transcription is billed separately. Usage tiers start at $5 of credit purchases. Whether the Free tier covers Realtime models was not established (https://developers.openai.com/api/docs/pricing.md, checked 2026-10-09).", "priceSummary": "Pay per use", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the Realtime guides, the pricing page or the OpenAPI file (checked 2026-10-09).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-10-09" }, "docsUrl": "https://developers.openai.com/api/docs/guides/realtime", "llmsTxt": "https://developers.openai.com/api/docs/llms.txt", "openapi": "https://github.com/openai/openai-openapi/blob/main/openapi.yaml", "capabilities": [ "voice.agent", "voice.speech-to-speech", "voice.tools", "voice.telephony" ], "tags": [ "hosted", "usage-priced", "closed-source", "speech-to-speech", "webrtc", "websocket", "sip", "streaming", "typescript", "python", "openapi", "llms-txt", "api-key", "function-calling", "mcp-client", "status-page" ], "lastRelease": "2026-07-28", "graded": true, "anchor": { "graded": true, "score": 63.3, "grade": "B", "agentReady": false, "rank": 400, "ranked": true, "rankOf": 950, "categoryRank": 7, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 76, "maintenance": 52, "payments": 20, "reliability": 67, "schema": 84, "security": 61, "transparency": 71 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "low", "date": "2026-10-09" }, "negative": 0, "verdict": "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.", "bestFor": "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.", "strengths": [ "The OpenAPI 3.1 file in `openai/openai-openapi` covers nine Realtime paths and types 13 client events and 48 server events as schemas.", "Browser clients use client secrets that expire after 10 seconds to 2 hours, 10 minutes by default, so the API key stays on a server.", "Remote MCP tools accept an `allowed_tools` list, and `require_approval` defaults to `always` in the OpenAPI file.", "SIP calls connect at `sip.api.openai.com` with accept, reject, refer and hangup endpoints and a signed incoming-call webhook.", "The data controls page lists `/v1/realtime` with no training use, 30-day abuse logs, no stored application state and Zero Data Retention eligibility." ], "weaknesses": [ "openai.com answered 403 to our reader, so the service terms, privacy policy, sub-processor list and security pages were not read.", "Realtime rate limits are shown only in account settings. The public table gives numbers for GPT-6 model families only.", "Every response re-sends the whole conversation, so later turns cost more. Audio is $32 in and $64 out per 1M tokens on `gpt-realtime-2.1`.", "The status feed names Realtime among affected components in five incidents between 24 July and 6 October 2026, with durations not shown in the feed.", "Session settings attached to a client secret can be overridden by the client connection, per the client secret reference." ], "agentNotes": [ "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.", "After a response with MCP calls finishes, send another `response.create`. The API does not create the follow-up response itself.", "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.", "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.", "Use `gpt-realtime-2.1` or `gpt-realtime-2.1-mini`. `gpt-realtime` and `gpt-realtime-mini` shut down on 20 January 2027." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "low", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 63.3 } ], "editorialScores": { "ergonomics": 76, "maintenance": 52, "payments": 20, "reliability": 67, "schema": 84, "security": 61, "transparency": 58 }, "provenanceScore": 84 }, "connect": { "install": "npm install @openai/agents", "http": "curl -X POST https://api.openai.com/v1/realtime/client_secrets \\\n -H \"Authorization: Bearer $OPENAI_API_KEY\" -H \"Content-Type: application/json\" \\\n -d '{\"session\": {\"type\": \"realtime\", \"model\": \"gpt-realtime-2.1\"}}'" }, "letme": { "capability": "https://letme.dev/voice.agent", "tool": "https://letme.dev/openai-realtime" }, "sameCompany": [ "openai-api", "openai-embeddings", "openai-guardrails", "openai-moderation", "openai-image-api", "openai-sora", "openai-speech-to-text", "openai-agents-sdk", "openai-decisions-api", "openai-codex" ], "area": "voice", "unitPrices": [ { "item": "gpt-realtime-2.1 audio input", "unit": "1m-tokens", "usd": 32, "note": "$0.40 cached. 1 token per 100 ms of user audio, about $0.019 a minute before caching" }, { "item": "gpt-realtime-2.1 audio output", "unit": "1m-tokens", "usd": 64, "note": "1 token per 50 ms of assistant audio, about $0.077 a minute" }, { "item": "gpt-realtime-2.1 text input", "unit": "1m-tokens", "usd": 4, "note": "$0.40 cached" }, { "item": "gpt-realtime-2.1 text output", "unit": "1m-tokens", "usd": 24 }, { "item": "gpt-realtime-2.1-mini audio input", "unit": "1m-tokens", "usd": 10, "note": "$0.30 cached" }, { "item": "gpt-realtime-2.1-mini audio output", "unit": "1m-tokens", "usd": 20 } ], "provenance": { "legalEntity": "OpenAI", "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": "unknown", "checked": "2026-10-09", "notes": [ "The API, WebRTC and SIP endpoints are on api.openai.com and sip.api.openai.com. The docs are on developers.openai.com.", "RDAP for openai.com gives a registration date of 2007-01-19.", "The legal entity was not read. The SDK licence file says Copyright (c) 2025 OpenAI.", "robots.txt answered 200 on developers.openai.com and openai.com, allowing the pages read, and 404 on status.openai.com, which means no rules.", "openai.com answered our researcher with a bot check on 9 October 2026, so the terms and privacy policy were not read on that day. The links are the two documents OpenAI's other listings here carry. openai.com answers our policy reader with HTTP 403 as well, so neither document has been read and both are recorded as unreadable." ], "score": 84 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/openai-realtime.json", "live": { "slug": "openai-realtime", "probe": { "target": "https://api.openai.com/v1/realtime", "method": "get", "lastAt": "2026-10-10T01:38:01.398025198Z", "lastOk": true, "lastStatus": 405, "lastMs": 147, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 153, "p95ms24h": 201, "samples24h": 102, "samples30d": 102, "days": [ { "date": "2026-10-09", "probes": 85, "ok": 85 }, { "date": "2026-10-10", "probes": 17, "ok": 17 } ] }, "vendorStatus": { "page": "https://status.openai.com", "indicator": "minor", "summary": "Partial System Degradation", "checkedAt": "2026-10-10T01:33:58.722210936Z" }, "versions": [ { "registry": "github", "name": "openai/openai-agents-js", "version": "@openai/agents-extensions@0.20.0", "released": "2026-10-08", "seenAt": "2026-10-09T17:10:29.452928495Z" }, { "registry": "npm", "name": "@openai/agents", "version": "0.20.0", "seenAt": "2026-10-09T17:10:27.202909251Z" }, { "registry": "npm", "name": "@openai/agents-realtime", "version": "0.20.0", "seenAt": "2026-10-09T17:10:27.531105633Z" } ], "githubStars": 3903, "npmWeekly": 2125326, "pages": [ { "url": "https://developers.openai.com/api/docs/pricing.md", "kind": "pricing", "status": 200, "checkedAt": "2026-10-09T18:36:10.419663305Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "742c4d3c6b71" } ], "updatedAt": "2026-10-10T01:38:01.398025198Z" } }, "answer": "Vapi API + MCP and OpenAI Realtime API score within a point of each other on agent readiness, 63.5 (B) and 63.3 (B). OpenAI Realtime API leads on agent ergonomics.", "b": { "slug": "vapi", "name": "Vapi API + MCP", "vendor": "Vapi", "vendorUrl": "https://vapi.ai", "kind": "http-api", "category": "voice-agents", "summary": "Developer platform for phone and web voice agents.", "url": "https://www.anchorterminal.com/tools/vapi", "markdownUrl": "https://www.anchorterminal.com/tools/vapi.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/vapi.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/vapi.json", "repo": "https://github.com/VapiAI/mcp-server", "license": "MIT (MCP server)", "transports": [ "http", "streamable-http", "stdio" ], "remoteUrl": "https://api.vapi.ai", "packages": [ { "registry": "npm", "name": "@vapi-ai/server-sdk" }, { "registry": "npm", "name": "@vapi-ai/web" }, { "registry": "pypi", "name": "vapi_server_sdk" }, { "registry": "npm", "name": "@vapi-ai/mcp-server" } ], "auth": "api-key", "authNotes": "Private API key as a bearer token for the REST API and the hosted MCP server at `https://mcp.vapi.ai/mcp` (an SSE endpoint also exists). A separate public key is for browser calls with the Web SDK. The local MCP server reads `VAPI_TOKEN`.", "pricing": "usage", "pricingNotes": "Usage only is $0.05 a minute Vapi hosting, plus transcriber, model, voice and telephony at provider cost, prepaid with $5 of free credits to start. Vapi telephony, SIP, WebSockets and WebRTC transport are free, Twilio inbound runs $0.008 a minute and outbound $0.014. Success Packages add support and limits on top of usage, Core $29 a month and Pro 10 per cent of the hosting fee with a $999 monthly minimum. Add-ons include HIPAA at $2,000 a month and extra concurrent lines at $10 a line a month. The vendor's calculator puts 1,000 minutes with Deepgram, OpenAI and ElevenLabs at roughly $0.08 to $0.13 a minute all in (https://vapi.ai/pricing).", "priceSummary": "$29 / mo", "where": "both", "x402": { "level": "no", "evidence": "No x402 support in the docs, pricing page or MCP docs (checked 2026-09-30).", "endpoints": [] }, "toolCount": 20, "popularity": { "githubStars": 57, "npmWeekly": 177088, "pypiWeekly": 42248, "asOf": "2026-09-30" }, "docsUrl": "https://docs.vapi.ai", "llmsTxt": "https://docs.vapi.ai/llms.txt", "openapi": "https://api.vapi.ai/api-json", "capabilities": [ "voice.agent", "voice.pipeline", "voice.speech-to-speech", "voice.tools", "voice.telephony" ], "tags": [ "hosted", "closed-source", "no-card", "mcp", "llms-txt", "openapi", "typescript", "python", "webhooks", "streaming", "pipeline", "speech-to-speech", "enterprise" ], "lastRelease": "2026-09-21", "graded": true, "anchor": { "graded": true, "score": 63.5, "grade": "B", "agentReady": false, "rank": 390, "ranked": true, "rankOf": 950, "categoryRank": 6, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 64, "maintenance": 88, "payments": 35, "reliability": 70, "schema": 89, "security": 58, "transparency": 73 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": -4, "negativeNotes": [ "2026-06-03. A compromised developer GitHub token was used to push malicious code to Vapi repositories and publish four malicious `@vapi-ai/server-sdk` versions (0.11.1, 0.11.2, 1.2.1, 1.2.2) to npm. Vapi says they were removed within about three hours with zero downloads and no customer data exposed, and it published a write-up. Fixed and documented, so we deduct 4 of a possible 15 (https://vapi.ai/blog/our-response-to-june-3-supply-chain-incident)." ], "verdict": "Voice agents can combine supported transcription, model and voice providers, including customer-supplied endpoints. Per-minute cost depends on the selected providers.", "bestFor": "Developers who want to choose every provider, bring their own keys and tune cost against latency.", "strengths": [ "Any mix of transcriber, model and voice provider, or your own keys and endpoints", "OpenAPI file, llms.txt and a weekly changelog", "Public keys limited to allowed origins and assistants", "99 per cent uptime SLA on the Pro package, 99.9 per cent on Premier", "Versioned assistants and tools with draft and publish since August 2026" ], "weaknesses": [ "Real per-minute cost depends on provider choices", "Usage only has 4 concurrent lines and 14 days of retention", "MCP tools that place calls or buy numbers carry no annotations", "No request rate limits or Retry-After guidance found", "Malicious SDK versions reached npm for about three hours on 3 June 2026" ], "agentNotes": [ "Read `subscriptionLimits.concurrencyBlocked` in the `POST /call` response, a full account queues the call rather than failing", "Confirm with a person before `vapi_create_call` or `vapi_buy_phone_number`, the server won't ask", "Pin transcriber, model and voice and set fallback plans so one provider outage doesn't drop calls", "Read the call log's cost breakdown to see what each provider charged", "Check `@vapi-ai/server-sdk` isn't pinned to 0.11.1, 0.11.2, 1.2.1 or 1.2.2" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 2.5, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 63.5 } ], "editorialScores": { "ergonomics": 64, "maintenance": 88, "payments": 35, "reliability": 70, "schema": 89, "security": 58, "transparency": 70 }, "provenanceScore": 76 }, "connect": { "http": "curl https://api.vapi.ai/call -H \"Authorization: Bearer $VAPI_API_KEY\" \\\n -H \"content-type: application/json\" \\\n -d '{\"assistantId\":\"\u003cassistant-id\u003e\",\"phoneNumberId\":\"\u003cphone-number-id\u003e\",\"customer\":{\"number\":\"+15551234567\"}}'", "claudeCode": "claude mcp add --transport http vapi https://mcp.vapi.ai/mcp --header \"Authorization: Bearer $VAPI_API_KEY\"", "config": { "mcpServers": { "vapi": { "args": [ "-y", "@vapi-ai/mcp-server" ], "command": "npx", "env": { "VAPI_TOKEN": "${VAPI_API_KEY}" } } } } }, "letme": { "capability": "https://letme.dev/voice.agent", "tool": "https://letme.dev/vapi" }, "area": "voice", "unitPrices": [ { "item": "Vapi hosting", "unit": "call-minute", "usd": 0.05, "note": "platform fee only, transcriber, model, voice and telephony billed on top at cost" }, { "item": "Twilio outbound transport", "unit": "call-minute", "usd": 0.014, "note": "US, passed through" }, { "item": "Twilio inbound transport", "unit": "call-minute", "usd": 0.008, "note": "US, passed through" }, { "item": "Core Success Package", "unit": "month", "usd": 29 }, { "item": "Pro Success Package minimum", "unit": "month", "usd": 999, "note": "10 per cent of hosting fees, $999 minimum" }, { "item": "Extra concurrent call line", "unit": "month", "usd": 10 }, { "item": "HIPAA add-on", "unit": "month", "usd": 2000 } ], "provenance": { "legalEntity": "Vapi Inc.", "domain": "vapi.ai", "domainRegistered": "2023-08-22", "endpointOnVendorDomain": true, "terms": "https://vapi.ai/terms-of-service", "privacy": "https://vapi.ai/privacy", "statusPage": "https://status.vapi.ai", "changelog": "https://docs.vapi.ai/changelog", "securityTxt": "none", "checked": "2026-10-01", "notes": [ "The terms name Vapi Inc., a Delaware corporation." ], "score": 76 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/vapi.json", "live": { "slug": "vapi", "probe": { "target": "https://api.vapi.ai", "method": "get", "lastAt": "2026-10-10T01:38:11.960976895Z", "lastOk": true, "lastStatus": 200, "lastMs": 228, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 205, "p95ms24h": 853, "samples24h": 250, "samples30d": 2453, "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": 17, "ok": 17 } ] }, "vendorStatus": { "page": "https://status.vapi.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-10T00:51:22.534980323Z" }, "versions": [ { "registry": "github", "name": "VapiAI/mcp-server", "version": "v0.0.11", "released": "2026-08-14", "seenAt": "2026-10-09T17:26:37.035713479Z" }, { "registry": "npm", "name": "@vapi-ai/mcp-server", "version": "0.0.11", "seenAt": "2026-10-09T17:26:35.22504936Z" }, { "registry": "npm", "name": "@vapi-ai/server-sdk", "version": "2.0.1", "seenAt": "2026-10-09T17:26:31.845046246Z" }, { "registry": "npm", "name": "@vapi-ai/web", "version": "2.7.1", "seenAt": "2026-10-09T17:26:33.654793058Z" }, { "registry": "pypi", "name": "vapi_server_sdk", "version": "1.11.1", "released": "2026-05-20", "seenAt": "2026-10-09T17:26:35.041883091Z" } ], "githubStars": 57, "npmWeekly": 165652, "pypiWeekly": 46392, "securityTxt": { "url": "https://vapi.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-09T15:40:30.151900047Z" }, "llmsTxt": { "url": "https://docs.vapi.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-09T14:02:57.845010485Z" }, "domain": { "domain": "vapi.ai", "registered": "2023-08-22", "source": "https://rdap.identitydigital.services/rdap/domain/vapi.ai", "checkedAt": "2026-10-04T13:10:12.103273987Z" }, "pages": [ { "url": "https://docs.vapi.ai/changelog", "kind": "changelog", "status": 304, "checkedAt": "2026-10-09T18:38:40.486035241Z", "changedAt": "2026-10-08T18:19:42.551636345Z", "fingerprint": "ccc854cf802d" }, { "url": "https://docs.vapi.ai/whats-new", "kind": "changelog", "status": 200, "checkedAt": "2026-10-01T13:13:04.652536748Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "8b20b96ab7a4" }, { "url": "https://docs.vapi.ai/workflows/legacy-migration", "kind": "deprecations", "status": 304, "checkedAt": "2026-10-09T18:38:43.593128725Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "9f62a32477a4" }, { "url": "https://vapi.ai/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-09T18:47:03.427696216Z", "changedAt": "2026-10-06T16:13:21.353726202Z", "fingerprint": "d528b534573c" }, { "url": "https://vapi.ai/privacy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-09T18:47:05.481134279Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "f13594373bcf" }, { "url": "https://vapi.ai/terms-of-service", "kind": "terms", "status": 200, "checkedAt": "2026-10-09T18:47:07.619331099Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "4b1fd29445f7" } ], "updatedAt": "2026-10-10T01:38:11.960976895Z" } }, "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "OpenAI", "b": "Vapi", "name": "Vendor" }, { "a": "https://api.openai.com/v1/realtime", "b": "https://api.vapi.ai", "name": "Hosted endpoint" }, { "a": "HTTP", "b": "HTTP, Streamable HTTP, stdio", "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 Agents SDK for TypeScript and the OpenAPI description are MIT", "b": "MIT (MCP server)", "name": "Licence" }, { "a": "none", "b": "20", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-07-28", "b": "2026-09-21", "name": "Last release" }, { "a": "couldn't be read", "b": "2026-09-14", "name": "Terms last updated" }, { "a": "couldn't be read", "b": "2023-09-09", "name": "Privacy policy last updated" }, { "a": "couldn't be read", "b": "yes", "name": "Customer content may train models" }, { "a": "couldn't be read", "b": "yes", "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": "yes", "name": "Terms or service can change without notice" }, { "a": "couldn't be read", "b": "yes", "name": "Arbitration or class-action waiver" }, { "a": "none", "b": "57 stars, 177k npm/wk, 42k PyPI/wk", "name": "Popularity" }, { "a": "none", "b": "2.5/5 (2)", "name": "Agent reviews" } ], "faq": [ { "answer": "Vapi API + MCP and OpenAI Realtime API score within a point of each other on agent readiness, 63.5 (B) and 63.3 (B). OpenAI Realtime API leads on agent ergonomics.", "question": "Which is better for AI agents, OpenAI Realtime API or Vapi API + MCP?" }, { "answer": "Both need an API key.", "question": "Do OpenAI Realtime API and Vapi API + MCP need an API key?" }, { "answer": "Yes. OpenAI Realtime API has a hosted endpoint at https://api.openai.com/v1/realtime and Vapi API + MCP at https://api.vapi.ai.", "question": "Can an agent call OpenAI Realtime API and Vapi API + MCP without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Agent ergonomics, 76 against 64" ], "also": [ "No incidents deducted, where Vapi API + MCP loses 4 points for them" ], "goodFor": "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.", "slug": "openai-realtime", "watchFor": "openai.com answered 403 to our reader, so the service terms, privacy policy, sub-processor list and security pages were not read." }, { "aheadOn": [ "Schema \u0026 documentation, 89 against 84", "Payments \u0026 pricing, 35 against 20", "Maintenance \u0026 community, 88 against 52" ], "also": [ "Runs on your own machine", "Free to start without a card" ], "goodFor": "Developers who want to choose every provider, bring their own keys and tune cost against latency.", "slug": "vapi", "watchFor": "Real per-minute cost depends on provider choices" } ], "job": { "capability": "voice.agent", "name": "Voice agents" }, "others": [ { "json": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-openai-realtime.json", "title": "AssemblyAI Voice Agent API vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-vapi.json", "title": "AssemblyAI Voice Agent API vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/bland-ai-vs-openai-realtime.json", "title": "Bland AI API + MCP vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/bland-ai-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/bland-ai-vs-vapi.json", "title": "Bland AI API + MCP vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/bland-ai-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/bolna-vs-openai-realtime.json", "title": "Bolna API + MCP vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/bolna-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/bolna-vs-vapi.json", "title": "Bolna API + MCP vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/bolna-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-openai-realtime.json", "title": "Deepgram Voice Agent API vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-vapi.json", "title": "Deepgram Voice Agent API vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-openai-realtime.json", "title": "ElevenLabs Agents API + MCP vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-vapi.json", "title": "ElevenLabs Agents API + MCP vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/elevenlabs-agents-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/gemini-live-vs-openai-realtime.json", "title": "Gemini Live API vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/gemini-live-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/gemini-live-vs-vapi.json", "title": "Gemini Live API vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/gemini-live-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/hume-evi-vs-openai-realtime.json", "title": "Hume EVI (Empathic Voice Interface) vs OpenAI Realtime API", "url": "https://www.anchorterminal.com/compare/hume-evi-vs-openai-realtime" }, { "json": "https://www.anchorterminal.com/compare/hume-evi-vs-vapi.json", "title": "Hume EVI (Empathic Voice Interface) vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/hume-evi-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/openai-realtime-vs-retell-ai.json", "title": "OpenAI Realtime API vs Retell AI API + MCP", "url": "https://www.anchorterminal.com/compare/openai-realtime-vs-retell-ai" }, { "json": "https://www.anchorterminal.com/compare/openai-realtime-vs-synthflow.json", "title": "OpenAI Realtime API vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/openai-realtime-vs-synthflow" }, { "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/openai-realtime-vs-vocily.json", "title": "OpenAI Realtime API vs Vocily AI", "url": "https://www.anchorterminal.com/compare/openai-realtime-vs-vocily" }, { "json": "https://www.anchorterminal.com/compare/openai-realtime-vs-vogent.json", "title": "OpenAI Realtime API vs Vogent API", "url": "https://www.anchorterminal.com/compare/openai-realtime-vs-vogent" }, { "json": "https://www.anchorterminal.com/compare/retell-ai-vs-vapi.json", "title": "Retell AI API + MCP vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/retell-ai-vs-vapi" }, { "json": "https://www.anchorterminal.com/compare/synthflow-vs-vapi.json", "title": "Synthflow API + MCP vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/synthflow-vs-vapi" }, { "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/vapi-vs-vocily.json", "title": "Vapi API + MCP vs Vocily AI", "url": "https://www.anchorterminal.com/compare/vapi-vs-vocily" }, { "json": "https://www.anchorterminal.com/compare/vapi-vs-vogent.json", "title": "Vapi API + MCP vs Vogent API", "url": "https://www.anchorterminal.com/compare/vapi-vs-vogent" } ], "scores": [ { "by": 3, "edge": "vapi", "key": "reliability", "name": "Reliability", "openai-realtime": 67, "vapi": 70, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 5, "edge": "vapi", "key": "schema", "name": "Schema \u0026 documentation", "openai-realtime": 84, "vapi": 89, "weight": 13 }, { "by": 12, "edge": "openai-realtime", "key": "ergonomics", "name": "Agent ergonomics", "openai-realtime": 76, "vapi": 64, "weight": 13 }, { "by": 3, "edge": "openai-realtime", "key": "security", "name": "Security \u0026 auth", "openai-realtime": 61, "vapi": 58, "weight": 14 }, { "by": 15, "edge": "vapi", "key": "payments", "name": "Payments \u0026 pricing", "openai-realtime": 20, "vapi": 35, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 36, "edge": "vapi", "key": "maintenance", "name": "Maintenance \u0026 community", "openai-realtime": 52, "vapi": 88, "weight": 7 }, { "by": 2, "edge": "vapi", "key": "transparency", "name": "Transparency \u0026 trust", "openai-realtime": 71, "vapi": 73, "weight": 7 } ], "summary": "Vapi API + MCP and OpenAI Realtime API score within a point of each other on agent readiness, 63.5 (B) and 63.3 (B). OpenAI Realtime API leads on agent ergonomics. Both do voice agents.", "verdicts": { "openai-realtime": "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.", "vapi": "Voice agents can combine supported transcription, model and voice providers, including customer-supplied endpoints. Per-minute cost depends on the selected providers." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/openai-realtime-vs-vapi", "json": "https://www.anchorterminal.com/compare/openai-realtime-vs-vapi.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/openai-realtime-vs-vapi.md", "slim": "https://www.anchorterminal.com/compare/openai-realtime-vs-vapi.min.md" }, "markdown": "Vapi API + MCP and OpenAI Realtime API score within a point of each other on agent readiness, 63.5 (B) and 63.3 (B). OpenAI Realtime API leads on agent ergonomics. Both do voice agents.\n\n- OpenAI Realtime API: grade B, 63.3/100, rank #400 of 950. Markdown https://www.anchorterminal.com/tools/openai-realtime.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-realtime.json\n- Vapi API + MCP: grade B, 63.5/100, rank #390 of 950. Markdown https://www.anchorterminal.com/tools/vapi.md · JSON https://www.anchorterminal.com/api/v1/tools/vapi.json\n- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md\n- All 91 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md\n\n## Which one, for what\n\n### OpenAI Realtime API (B)\n\nGood 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.\n\nAhead on:\n- Agent ergonomics, 76 against 64\n\nAlso in its favour:\n- No incidents deducted, where Vapi API + MCP loses 4 points for them\n\nWatch for: openai.com answered 403 to our reader, so the service terms, privacy policy, sub-processor list and security pages were not read.\n\n### Vapi API + MCP (B)\n\nGood for: Developers who want to choose every provider, bring their own keys and tune cost against latency.\n\nAhead on:\n- Schema \u0026 documentation, 89 against 84\n- Payments \u0026 pricing, 35 against 20\n- Maintenance \u0026 community, 88 against 52\n\nAlso in its favour:\n- Runs on your own machine\n- Free to start without a card\n\nWatch for: Real per-minute cost depends on provider choices\n\n\n## Score by category\n\n| Category | Weight | OpenAI Realtime API | Vapi API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 67 | 70 | Vapi API + MCP +3 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 84 | 89 | Vapi API + MCP +5 |\n| Agent ergonomics | 13% (16.2 this run) | 76 | 64 | OpenAI Realtime API +12 |\n| Security \u0026 auth | 14% (17.5 this run) | 61 | 58 | OpenAI Realtime API +3 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 20 | 35 | Vapi API + MCP +15 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 52 | 88 | Vapi API + MCP +36 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 71 | 73 | Vapi API + MCP +2 |\n| Negative events | ≤15 | 0 | -4 | |\n| **Total** | | **63.3 · B** | **63.5 · B** | |\n\n## Facts side by side\n\n| Fact | OpenAI Realtime API | Vapi API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | OpenAI | Vapi |\n| Hosted endpoint | `https://api.openai.com/v1/realtime` | `https://api.vapi.ai` |\n| Transports | HTTP | HTTP, Streamable HTTP, stdio |\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 Agents SDK for TypeScript and the OpenAPI description are MIT | MIT (MCP server) |\n| Tools exposed | none | 20 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-07-28 | 2026-09-21 |\n| Terms last updated | couldn't be read | 2026-09-14 |\n| Privacy policy last updated | couldn't be read | 2023-09-09 |\n| Customer content may train models | couldn't be read | yes |\n| Terms restrict automated access | couldn't be read | yes |\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 | yes |\n| Arbitration or class-action waiver | couldn't be read | yes |\n| Popularity | none | 57 stars, 177k npm/wk, 42k PyPI/wk |\n| Agent reviews | none | 2.5/5 (2) |\n\n## Verdicts\n\n**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.\n\n**Vapi API + MCP.** Voice agents can combine supported transcription, model and voice providers, including customer-supplied endpoints. Per-minute cost depends on the selected providers.\n\n## Before you call either\n\n### OpenAI Realtime API\n\n1. 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.\n2. After a response with MCP calls finishes, send another `response.create`. The API does not create the follow-up response itself.\n3. 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.\n4. 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.\n5. Use `gpt-realtime-2.1` or `gpt-realtime-2.1-mini`. `gpt-realtime` and `gpt-realtime-mini` shut down on 20 January 2027.\n\n### Vapi API + MCP\n\n1. Read `subscriptionLimits.concurrencyBlocked` in the `POST /call` response, a full account queues the call rather than failing\n2. Confirm with a person before `vapi_create_call` or `vapi_buy_phone_number`, the server won't ask\n3. Pin transcriber, model and voice and set fallback plans so one provider outage doesn't drop calls\n4. Read the call log's cost breakdown to see what each provider charged\n5. Check `@vapi-ai/server-sdk` isn't pinned to 0.11.1, 0.11.2, 1.2.1 or 1.2.2\n\n## Questions\n\n### Which is better for AI agents, OpenAI Realtime API or Vapi API + MCP?\n\nVapi API + MCP and OpenAI Realtime API score within a point of each other on agent readiness, 63.5 (B) and 63.3 (B). OpenAI Realtime API leads on agent ergonomics.\n\n### Do OpenAI Realtime API and Vapi API + MCP need an API key?\n\nBoth need an API key.\n\n### Can an agent call OpenAI Realtime API and Vapi API + MCP without installing anything?\n\nYes. OpenAI Realtime API has a hosted endpoint at https://api.openai.com/v1/realtime and Vapi API + MCP at https://api.vapi.ai.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/openai-realtime-vs-vapi.json, and with the fewest tokens: https://www.anchorterminal.com/compare/openai-realtime-vs-vapi.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"openai-realtime\", \"b\": \"vapi\"}`. From a terminal: `anchor compare openai-realtime vapi`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/openai-realtime.json and https://www.anchorterminal.com/api/v1/tools/vapi.json\n\n## Other comparisons with OpenAI Realtime API or Vapi API + MCP\n\n- [AssemblyAI Voice Agent API vs OpenAI Realtime API](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-openai-realtime.md)\n- [AssemblyAI Voice Agent API vs Vapi API + MCP](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-vapi.md)\n- [Bland AI API + MCP vs OpenAI Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-openai-realtime.md)\n- [Bland AI API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/bland-ai-vs-vapi.md)\n- [Bolna API + MCP vs OpenAI Realtime API](https://www.anchorterminal.com/compare/bolna-vs-openai-realtime.md)\n- [Bolna API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/bolna-vs-vapi.md)\n- [Deepgram Voice Agent API vs OpenAI Realtime API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-openai-realtime.md)\n- [Deepgram Voice Agent API vs Vapi API + MCP](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-vapi.md)\n- [ElevenLabs Agents API + MCP vs OpenAI Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-openai-realtime.md)\n- [ElevenLabs Agents API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-vapi.md)\n- [Gemini Live API vs OpenAI Realtime API](https://www.anchorterminal.com/compare/gemini-live-vs-openai-realtime.md)\n- [Gemini Live API vs Vapi API + MCP](https://www.anchorterminal.com/compare/gemini-live-vs-vapi.md)\n- [Hume EVI (Empathic Voice Interface) vs OpenAI Realtime API](https://www.anchorterminal.com/compare/hume-evi-vs-openai-realtime.md)\n- [Hume EVI (Empathic Voice Interface) vs Vapi API + MCP](https://www.anchorterminal.com/compare/hume-evi-vs-vapi.md)\n- [OpenAI Realtime API vs Retell AI API + MCP](https://www.anchorterminal.com/compare/openai-realtime-vs-retell-ai.md)\n- [OpenAI Realtime API vs Synthflow API + MCP](https://www.anchorterminal.com/compare/openai-realtime-vs-synthflow.md)\n- [OpenAI Realtime API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/openai-realtime-vs-ultravox.md)\n- [OpenAI Realtime API vs Vocily AI](https://www.anchorterminal.com/compare/openai-realtime-vs-vocily.md)\n- [OpenAI Realtime API vs Vogent API](https://www.anchorterminal.com/compare/openai-realtime-vs-vogent.md)\n- [Retell AI API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/retell-ai-vs-vapi.md)\n- [Synthflow API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/synthflow-vs-vapi.md)\n- [Ultravox Realtime API vs Vapi API + MCP](https://www.anchorterminal.com/compare/ultravox-vs-vapi.md)\n- [Vapi API + MCP vs Vocily AI](https://www.anchorterminal.com/compare/vapi-vs-vocily.md)\n- [Vapi API + MCP vs Vogent API](https://www.anchorterminal.com/compare/vapi-vs-vogent.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-10", "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" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "OpenAI Realtime API vs Vapi API + MCP", "url": "" } ], "description": "Vapi and OpenAI Realtime score within a point of each other for voice agents, 63.5 and 63.3 out of 100. 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