{ "data": { "a": { "slug": "inworld-realtime", "name": "Inworld Realtime API", "vendor": "Inworld AI", "vendorUrl": "https://inworld.ai", "kind": "http-api", "category": "voice-agents", "summary": "Inworld's Realtime API runs spoken conversations over WebSocket or WebRTC, chaining Inworld STT, an LLM chosen by the developer and Inworld TTS, with turn detection, interruptions and tool calling. It follows OpenAI's Realtime protocol.", "url": "https://www.anchorterminal.com/tools/inworld-realtime", "markdownUrl": "https://www.anchorterminal.com/tools/inworld-realtime.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/inworld-realtime.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/inworld-realtime.json", "dns": "inworld-realtime.grade.anchorterminal.com", "transports": [ "websocket", "http" ], "packages": [ { "registry": "npm", "name": "@inworld/cli" } ], "auth": "api-key", "authNotes": "Servers send `Authorization: Basic` with the Base64 `key_id:secret` credential. Browsers send `Authorization: Bearer` with a session token minted server side. The `key` query parameter in the WebSocket URL is a session ID, not a secret.", "pricing": "usage", "pricingNotes": "No per-minute or per-session price. A session is billed as its STT ($0.10 to $0.15 an hour), its LLM tokens at the model's rate and its TTS characters (TTS-2 from $25 per million on the free plan). Segments already sent to TTS are billed after an interruption.", "priceSummary": "Pay per use", "where": "local", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs, llms.txt or pricing page (checked 2026-11-06). Plans and credits are bought in the Portal.", "endpoints": [] }, "toolCount": 0, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-11-06" }, "docsUrl": "https://docs.inworld.ai/realtime/overview", "llmsTxt": "https://docs.inworld.ai/llms.txt", "capabilities": [ "voice.agent", "voice.pipeline", "voice.tools", "voice.telephony" ], "tags": [ "hosted", "usage", "free-tier", "closed-source", "llms-txt", "streaming", "websocket", "webrtc", "openai-compatible", "enterprise" ], "lastRelease": "2026-10-16", "graded": true, "anchor": { "graded": true, "score": 60.1, "grade": "C", "agentReady": false, "rank": 668, "ranked": true, "rankOf": 1486, "categoryRank": 12, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 68, "maintenance": 71, "payments": 40, "reliability": 62, "schema": 60, "security": 58, "transparency": 63 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-06" }, "negative": 0, "verdict": "Inworld's Realtime API speaks OpenAI's Realtime protocol over WebSocket or WebRTC, with a choice of LLM, client-side tools and dated release notes. Cost is the sum of STT, LLM and TTS usage with no per-minute price, there is no machine-readable event schema, and status history couldn't be read.", "bestFor": "Teams moving off OpenAI's Realtime API who want a choice of LLM and Inworld voices.", "strengths": [ "Follows OpenAI's Realtime events, with a migration guide that changes only the URL, key and a few defaults", "Dated release notes name affected clients and required actions for each compatibility change", "A choice of LLM through Inworld's router, with prompt caching on Anthropic models", "Concurrent sessions from 10 on the free plan to 1,000 on Growth", "Zero data retention covers session content from the Developer plan up" ], "weaknesses": [ "No per-minute price. A session's cost depends on STT, LLM tokens and TTS characters, and interrupted segments are still billed", "No AsyncAPI or other machine-readable schema for the socket events", "Status history couldn't be read, and an SLA exists only for Enterprise", "The 21 July 2026 release changed response and item shapes for existing clients", "Zero data retention doesn't cover requests routed to third-party LLM providers" ], "agentNotes": [ "Set the auto follow-up off if your client sends its own `response.create` after a tool result, or replies double", "Read `response.done` usage as an estimate and mute input audio when nobody speaks, since STT bills every second sent", "Use `response.speak` for fixed greetings, which skips the LLM", "Treat `unsupported_field` errors as warnings and keep the session open", "Mint browser session tokens on your server and never ship the Basic credential to a client" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 60.1 } ], "editorialScores": { "ergonomics": 68, "maintenance": 71, "payments": 40, "reliability": 62, "schema": 60, "security": 58, "transparency": 51 }, "provenanceScore": 75, "checked": { "categories": { "ergonomics": "2026-11-06", "maintenance": "2026-11-06", "payments": "2026-11-06", "reliability": "2026-11-06", "schema": "2026-11-06", "security": "2026-11-06", "transparency": "2026-11-06" }, "last": "2026-11-06", "oldest": "2026-11-06", "stale": false, "staleAfterDays": 90 } }, "connect": { "install": "npm install -g @inworld/cli" }, "letme": { "capability": "https://letme.dev/voice.agent", "tool": "https://letme.dev/inworld-realtime" }, "sameCompany": [ "inworld-stt", "inworld-tts", "inworld-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Speech recognition in a session", "unit": "audio-minute", "usd": 0.0025, "note": "STT-1 at $0.15 an hour On-Demand, $0.10 on paid plans" }, { "item": "Agent speech, TTS-2", "unit": "1m-chars", "usd": 25, "note": "free On-Demand plan; lower on paid plans" } ], "provenance": { "legalEntity": "Theai, Inc. dba Inworld AI", "domain": "inworld.ai", "domainRegistered": "", "endpointOnVendorDomain": true, "terms": "https://inworld.ai/terms", "privacy": "https://inworld.ai/privacy", "statusPage": "https://status.inworld.ai", "changelog": "https://docs.inworld.ai/release-notes/realtime", "securityTxt": "none", "checked": "2026-11-06", "notes": [ "The Terms of Service (effective 11 June 2025) are an agreement with Theai, Inc. dba Inworld AI under California law, with courts in Santa Clara. The Privacy Notice (last updated 18 January 2026) names Theai, Inc.", "inworld.ai/.well-known/security.txt returns 404. The security page links a vulnerability report form.", "status.inworld.ai runs the open-source issue-status app, which draws incidents from GitHub issues in inworld-ai/inworld-issue-status. Its history wasn't read, because GitHub's robots.txt couldn't be read from our environment.", "inworld.ai's robots.txt allows Claude agents on the paths read and sets `Content-Signal: ai-train=no, search=yes, ai-input=no`. docs.inworld.ai has no such signal.", "The domain's registration date wasn't established, because the RDAP lookup failed.", "firstReleased is left empty. The public Realtime release notes start on 21 July 2026 and no launch date was found." ], "score": 75 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/inworld-realtime.json", "live": { "slug": "inworld-realtime", "vendorStatus": { "page": "https://status.inworld.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-11-07T04:47:57.03709454Z" }, "versions": [ { "registry": "npm", "name": "@inworld/cli", "version": "1.5.0", "seenAt": "2026-11-06T23:35:04.551623033Z" } ], "npmWeekly": 290, "securityTxt": { "url": "https://inworld.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-11-07T16:01:11.794771951Z" }, "llmsTxt": { "url": "https://docs.inworld.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:32:46.028273902Z" }, "pages": [ { "url": "https://docs.inworld.ai/release-notes/realtime", "kind": "changelog", "status": 200, "checkedAt": "2026-11-07T14:06:42.218731652Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "9ae0f1f05b69" }, { "url": "https://inworld.ai/privacy", "kind": "privacy", "status": 304, "checkedAt": "2026-11-07T14:11:39.031139211Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "99dc39a9de92" }, { "url": "https://inworld.ai/terms", "kind": "terms", "status": 304, "checkedAt": "2026-11-07T14:11:41.181276356Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "777d881cbf9b" } ], "updatedAt": "2026-11-07T16:01:11.794771951Z" } }, "answer": "Inworld Realtime API scores 60.1 (C) on agent readiness against Synthflow API + MCP's 47.3 (D), and leads in 5 of 7 scored categories. Synthflow API + MCP leads on transparency \u0026 trust.", "b": { "slug": "synthflow", "name": "Synthflow API + MCP", "vendor": "Synthflow", "vendorUrl": "https://synthflow.ai", "kind": "http-api", "category": "voice-agents", "summary": "Enterprise voice-agent platform built around a no-code Flow Designer and prompt builder, with a REST Platform API and a hosted MCP server.", "url": "https://www.anchorterminal.com/tools/synthflow", "markdownUrl": "https://www.anchorterminal.com/tools/synthflow.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/synthflow.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/synthflow.json", "dns": "synthflow.grade.anchorterminal.com", "repo": "https://github.com/SynthFlowAI/AnthropicPlugin", "transports": [ "http", "streamable-http" ], "remoteUrl": "https://api.synthflow.ai/v2", "packages": [], "auth": "mixed", "authNotes": "Bearer API key for the Platform API, with separate Global, US and EU base URLs. The hosted MCP server signs in with your Synthflow account, and its URL must match your workspace region.", "pricing": "paid", "pricingNotes": "Sales-led only. Synthflow is sold as an annual enterprise agreement scoped on call volume, concurrency, telephony, integrations and security, with no free plan, trial or rate by the minute. The earlier self-serve Pro, Growth and Agency plans are no longer sold (https://synthflow.ai/pricing).", "priceSummary": "Paid", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs, pricing page or MCP docs (checked 2026-11-04).", "endpoints": [] }, "toolCount": 66, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://docs.synthflow.ai", "llmsTxt": "https://docs.synthflow.ai/llms.txt", "openapi": "https://docs.synthflow.ai/openapi.json", "capabilities": [ "voice.agent", "voice.pipeline", "voice.tools", "voice.telephony" ], "tags": [ "hosted", "closed-source", "mcp", "llms-txt", "openapi", "webhooks", "pipeline", "enterprise" ], "lastRelease": "2026-10-23", "graded": true, "anchor": { "graded": true, "score": 47.3, "grade": "D", "agentReady": false, "rank": 1142, "ranked": true, "rankOf": 1486, "categoryRank": 21, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 45, "maintenance": 65, "payments": 0, "reliability": 55, "schema": 62, "security": 55, "transparency": 75 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-04" }, "negative": -3, "negativeNotes": [ "-3, a change that broke working requests, posted after it took effect. From 12:00 UTC on 23 October to 16:00 UTC on 26 October 2026, `PUT /v2/subaccounts/{subaccount_id}` requests that included `operation_type` or `products` failed with 400 after an internal infrastructure change, and nothing in those requests was saved. Synthflow reverted it and posted the account on its status page afterwards. https://status.synthflow.ai/feed.atom" ], "verdict": "Synthflow publishes a dated changelog with dated deprecation notices, Global, US and EU regions for the API and MCP server, and a trust centre listing SOC 2 Type 2 and ISO 27001. Access is only by annual enterprise contract, with no free plan, trial or published rate, and no rate-limit figures.", "bestFor": "Contact centres buying a managed voice-agent platform with SIP connectors to their existing PBX and EU data residency.", "strengths": [ "Changelog posts on ten days between 9 and 30 October 2026, with API Changes and Deprecation Notices categories and an RSS feed", "Global, US and EU regions for the API and the MCP server, each with its own base URL", "Status page with Dashboard, API and calling components per region, and incidents written up with cause and scope", "Trust centre lists SOC 2 Type 2, ISO/IEC 27001 and HIPAA, with reports on NDA request and 20 named subprocessors with purposes and locations", "Per-agent 30-day retention toggle and PII redaction for transcripts, webhooks and logs" ], "weaknesses": [ "Annual enterprise contract only, with no free plan, trial or rate by the minute", "No published concurrency or calls-per-second figures, and no backoff or idempotency guidance for 429", "No official SDK packages, and the Claude plugin repository has no CI", "`PUT /v2/subaccounts` rejected two documented fields from 23 to 26 October 2026 after an internal change", "`publish_agent_draft`, `rollback_agent_version` and `batch_update_agents_by_filter` run through MCP without confirmation" ], "agentNotes": [ "Use the MCP and API base URL that matches the workspace region (Global, US or EU)", "Send destructive MCP tools again with `confirmed=true` only after a person approves", "Expect 429 when concurrency or calls per second run out, and leave at least a second between call starts outside Campaigns", "Move from `recording_url` to the Get a recording endpoint before 10 January 2027", "Read the transfer failure reason on a failed transfer before retrying it" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 2, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "D", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 47.3 } ], "editorialScores": { "ergonomics": 45, "maintenance": 65, "payments": 0, "reliability": 55, "schema": 62, "security": 55, "transparency": 68 }, "provenanceScore": 82, "checked": { "categories": { "ergonomics": "2026-11-04", "maintenance": "2026-11-04", "payments": "2026-11-04", "reliability": "2026-11-04", "schema": "2026-11-04", "security": "2026-11-04", "transparency": "2026-11-04" }, "last": "2026-11-04", "lastMoved": "2026-11-04", "oldest": "2026-11-04", "stale": false, "staleAfterDays": 90 } }, "connect": { "http": "curl -X POST https://api.synthflow.ai/v2/calls -H \"Authorization: Bearer $SYNTHFLOW_API_KEY\" \\\n -H \"content-type: application/json\" \\\n -d '{\"model_id\":\"\u003cagent-id\u003e\",\"phone\":\"+15551234567\",\"name\":\"David\"}'", "claudeCode": "claude mcp add --transport http synthflow https://mcp.synthflow.ai/mcp" }, "letme": { "capability": "https://letme.dev/voice.agent", "tool": "https://letme.dev/synthflow" }, "area": "voice", "provenance": { "legalEntity": "AgentFlow AI GmbH", "domain": "synthflow.ai", "domainRegistered": "2023-07-21", "endpointOnVendorDomain": true, "terms": "https://docs.synthflow.ai/terms-conditions", "privacy": "https://docs.synthflow.ai/privacy-policy", "statusPage": "https://status.synthflow.ai", "changelog": "https://docs.synthflow.ai/changelog", "securityTxt": "none", "checked": "2026-11-04", "notes": [ "The Subscriber Terms (version 1.0, last updated 13 May 2026) name AgentFlow AI GmbH, registered at the local court of Charlottenburg under HRB 255004 B, Kurfürstendamm 15, 10719 Berlin.", "The status page at status.synthflow.ai runs on incident.io, with Dashboard, API and End to End calling components for Legacy, US and EU infrastructure.", "synthflow.ai/.well-known/security.txt returns 404 (4 November 2026). The trust centre at security.synthflow.ai is run on SafeBase.", "The registration date of synthflow.ai has no first-hand source we could read on 4 November 2026." ], "score": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/synthflow.json", "live": { "slug": "synthflow", "probe": { "target": "https://api.synthflow.ai/v2", "method": "get", "lastAt": "2026-11-07T18:20:58.022084777Z", "lastOk": true, "lastStatus": 404, "lastMs": 286, "authRequired": false, "uptime24h": 100, "uptime30d": 99.99, "p50ms24h": 218, "p95ms24h": 445, "samples24h": 239, "samples30d": 7910, "days": [ { "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": 256, "ok": 256 }, { "date": "2026-10-19", "probes": 255, "ok": 255 }, { "date": "2026-10-20", "probes": 252, "ok": 252 }, { "date": "2026-10-21", "probes": 253, "ok": 253 }, { "date": "2026-10-22", "probes": 253, "ok": 253 }, { "date": "2026-10-23", "probes": 248, "ok": 248 }, { "date": "2026-10-24", "probes": 251, "ok": 251 }, { "date": "2026-10-25", "probes": 250, "ok": 249 }, { "date": "2026-10-26", "probes": 252, "ok": 252 }, { "date": "2026-10-27", "probes": 249, "ok": 249 }, { "date": "2026-10-28", "probes": 250, "ok": 250 }, { "date": "2026-10-29", "probes": 249, "ok": 249 }, { "date": "2026-10-30", "probes": 249, "ok": 249 }, { "date": "2026-10-31", "probes": 251, "ok": 251 }, { "date": "2026-11-01", "probes": 249, "ok": 249 }, { "date": "2026-11-02", "probes": 250, "ok": 250 }, { "date": "2026-11-03", "probes": 248, "ok": 248 }, { "date": "2026-11-04", "probes": 246, "ok": 246 }, { "date": "2026-11-05", "probes": 185, "ok": 185 }, { "date": "2026-11-06", "probes": 241, "ok": 241 }, { "date": "2026-11-07", "probes": 187, "ok": 187 } ] }, "vendorStatus": { "page": "https://status.synthflow.ai", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-11-07T18:22:04.672404132Z" }, "githubStars": 0, "securityTxt": { "url": "https://synthflow.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-11-07T16:00:37.012918414Z" }, "llmsTxt": { "url": "https://docs.synthflow.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:34:05.343006996Z" }, "domain": { "domain": "synthflow.ai", "registered": "2023-07-21", "source": "https://rdap.identitydigital.services/rdap/domain/synthflow.ai", "checkedAt": "2026-11-01T14:08:46.202924518Z" }, "pages": [ { "url": "https://docs.synthflow.ai/changelog", "kind": "changelog", "status": 200, "checkedAt": "2026-11-07T14:08:16.305098813Z", "changedAt": "2026-11-06T13:30:35.671235385Z", "fingerprint": "e371e7e41e75" }, { "url": "https://synthflow.ai/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-11-07T14:21:37.566787318Z", "changedAt": "2026-11-06T13:43:04.747170265Z", "fingerprint": "a5a3170c3c78" }, { "url": "https://docs.synthflow.ai/privacy-policy", "kind": "privacy", "status": 200, "checkedAt": "2026-11-07T14:08:18.832503841Z", "changedAt": "2026-10-29T05:06:05.220387717Z", "fingerprint": "3738d5638558" }, { "url": "https://docs.synthflow.ai/terms-conditions", "kind": "terms", "status": 200, "checkedAt": "2026-11-07T14:08:20.742266544Z", "changedAt": "2026-10-29T05:06:07.003894551Z", "fingerprint": "79b6301d26e0" } ], "mcpTools": { "url": "https://mcp.synthflow.ai/mcp", "checkedAt": "2026-11-07T01:48:11.228612533Z", "status": "auth", "note": "asks for credentials before listing its tools", "changedAt": "2026-11-07T01:48:11.228612533Z" }, "github": { "repo": "synthflowai/anthropicplugin", "checkedAt": "2026-11-02T09:29:46.136470387Z", "stars": 0, "archived": false, "issuesEnabled": true, "pushedAt": "2026-07-30T07:56:34Z", "openIssues": 0, "openPRs": 0, "issuesOpened90d": 0, "issuesClosed90d": 0, "prsMerged90d": 0 }, "updatedAt": "2026-11-07T18:22:04.672404132Z" } }, "edges": [ { "by": 40, "category": "payments", "leads": "inworld-realtime", "name": "Payments \u0026 pricing", "reasons": { "a": "No x402, MPP or L402 (0). No per-session price, but each billed part (STT per hour, TTS per character, LLM per token) is priced publicly (20). On-Demand includes free STT and TTS allowances and lists no payment method, though some premium LLMs need a card on file (20). A person signs up in a browser before a key exists (0). Total 40.", "b": "No x402, MPP or L402 (0 of 40). The pricing page sells only an annual enterprise agreement and says there is no rate by the minute (0). It also says there is no free plan or trial (0). An agent can't get access without a sales process (0)." }, "scores": { "a": 40, "b": 0 } }, { "by": 23, "category": "ergonomics", "leads": "inworld-realtime", "name": "Agent ergonomics", "reasons": { "a": "Scored as an API. Conversation history defaults to the last 100 items, can be trimmed, and can be cached on Anthropic models, and every `response.done` carries a `usage` block (18 of 25). No lists to page. Output controls are modalities, turn detection settings, optional transcription and `response.speak` (12 of 20). Error events follow OpenAI's `type` and `code` shape, unsupported fields come back as non-fatal `unsupported_field` warnings, and `item_not_found` names the bad parameter (14 of 20). Tools run on the client and a follow-up response starts automatically after a tool result. Nothing covers side effects of a tool call cut off by an interruption (12 of 20). Works with OpenAI Realtime clients after changing the URL and key, with no Inworld Realtime SDK (12 of 15). Total 68.", "b": "The hosted MCP server lists 66 tools in seven groups, with no toolsets or read-only subset; `get_more_tools` only reports whether more exist (5 of 25). Call and log lists filter and page (14 of 20). Errors carry codes and named transfer failure reasons (13 of 20). Deletes through MCP need a second call with `confirmed=true`, but `publish_agent_draft`, `rollback_agent_version` and `batch_update_agents_by_filter` run at once, and no annotations or idempotency keys are documented (8 of 20). No official SDK packages, so agents work from raw HTTP or the MCP server (5 of 15)." }, "scores": { "a": 68, "b": 45 } }, { "by": 12, "category": "transparency", "leads": "synthflow", "name": "Transparency \u0026 trust", "reasons": { "a": "Closed service with clear terms naming Theai, Inc. dba Inworld AI (15). The ZDR page says what a session keeps and that third-party LLM requests aren't covered, but the terms and privacy notice disagree on training (12 of 30). Release notes flag potentially breaking changes with the clients affected and what to do, without stating a notice period (14 of 20). US headquarters with EU and India residency on Enterprise, and no sub-processor list in the docs, while sessions may route to third-party LLM providers (10 of 20). Total 51.", "b": "Closed platform with clear terms. The Subscriber Terms (version 1.0, 13 May 2026) name AgentFlow AI GmbH, Berlin, HRB 255004 B (15). Recordings, transcripts and caller IDs can be set to delete after 30 days per agent, PII redaction is available, and a DPA and BAA are offered. Otherwise the privacy policy keeps data until it is no longer needed, with no platform retention period (18 of 30). The changelog's Deprecation Notices carry dates. `recording_url` on the calls endpoints ends on 10 January 2027, announced on 22 October, and Salesforce actions need reconnecting by 30 November 2026. No written policy with a notice period found (15). The trust centre page lists 20 subprocessors, each with its purpose and processing location, among them AWS, Google Cloud, Microsoft Azure, OpenAI, Anthropic, Deepgram, ElevenLabs and Twilio. 18 process in the US and EU and two, Cerebrium and Hex Tech, in the US. The docs give Global, US and EU regions (20). 15 + 18 + 15 + 20 = 68." }, "scores": { "a": 63, "b": 75 } }, { "by": 7, "category": "reliability", "leads": "inworld-realtime", "name": "Reliability", "reasons": { "a": "Hosted reading of the checklist. status.inworld.ai is a public status page (20), with history we couldn't read, as on inworld-tts (5). Concurrent sessions are published per plan, 10 on On-Demand up to 1,000 on Growth (15). The rate limits page gives exponential backoff with jitter and Retry-After on longer windows, and sessions emit `rate_limits.updated`, with nothing on reconnecting a dropped session (12 of 15). An SLA appears only in the Enterprise column, with no terms (0). No preview or beta label on the Realtime API (10). 20 + 5 + 15 + 12 + 0 + 10 = 62.", "b": "Status page at status.synthflow.ai, now on incident.io, with Dashboard, API and End to End calling components for the Legacy, US and EU infrastructure, and a 90-day history on the page that covers the window from 6 August (20). In the 90 days from 6 August there were post-call AI outputs missing from webhooks from 08:20 to 11:10 UTC on 7 August (calls and webhook delivery unaffected), 9 to 12 minutes of failed calls in the EU and US regions with intermittent warm-transfer failures on 17 August, a white-label login fault on 7 September, `PUT /v2/subaccounts` rejecting two fields from 23 to 26 October, dashboard access and slower API responses on 26 October, and the settings page and SSO login unavailable for some workspaces from 27 October, which also hid some subaccount workspaces in the dashboard. Each touched one function, region or group of requests, so all read as minor. The 7 August webhook fault was counted as a major on 1 October (20). Concurrency and calls-per-second limits are set per contract and no numbers are published (0). The concurrency page documents 429 on reaching either limit and suggests a 1-second delay between calls started from automation tools, with no Retry-After, backoff or idempotency guidance. Earlier partial kept (5). No SLA published, and the pricing page sets availability terms in each agreement (0). The Platform API is generally available (10)." }, "scores": { "a": 62, "b": 55 } }, { "by": 6, "category": "maintenance", "leads": "inworld-realtime", "name": "Maintenance \u0026 community", "reasons": { "a": "Release note of 16 October 2026 (`cache_transcript`), 21 days ago (30). Three dated Realtime entries in the 90 days from 8 August, on 14 September, 23 September and 16 October (20). Discord and support@inworld.ai, with no evidence of answers read (8 of 15). Works with OpenAI's Realtime clients and the CLI is current at 1.5.0, but there is no Inworld Realtime SDK (8 of 15). CLI on npm under MIT, CI not read (5 of 10). Total 71.", "b": "API changes dated 23 October 2026 (List agent versions, new MCP server tools), 12 days before this check. The 30 October entry is a dashboard function the API doesn't serve (30). Ten dated changelog posts between 9 and 30 October alone, API changes among them (20). Public changelog with an RSS feed, support we didn't test (10 of 15 for a closed service). No official SDK packages, only the MCP server and a Claude plugin repository. Earlier partial kept (5 of 15). No packages. The plugin repository has no CI and its last commit is 30 July 2026. Down from 3, which no package earned (0)." }, "scores": { "a": 71, "b": 65 } } ], "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "Inworld AI", "b": "Synthflow", "name": "Vendor" }, { "a": "no (local only)", "b": "https://api.synthflow.ai/v2", "name": "Hosted endpoint" }, { "a": "websocket, HTTP", "b": "HTTP, Streamable HTTP", "name": "Transports" }, { "a": "API key", "b": "OAuth or key", "name": "Auth" }, { "a": "Pay per use", "b": "Paid", "name": "Pricing" }, { "a": "$25 per 1M characters", "b": "not published", "name": "Price for voice agents" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "0", "b": "66", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-10-16", "b": "2026-10-23", "name": "Last release" }, { "a": "2025-06-11", "b": "2026-05-13", "name": "Terms last updated" }, { "a": "2026-01-18", "b": "no date given", "name": "Privacy policy last updated" }, { "a": "not found in the text", "b": "not found in the text", "name": "Customer content may train models" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict automated access" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict benchmarking" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms or service can change without notice" }, { "a": "not found in the text", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "none", "b": "2/5 (2)", "name": "Agent reviews" } ], "faq": [ { "answer": "Inworld Realtime API scores 60.1 (C) on agent readiness against Synthflow API + MCP's 47.3 (D), and leads in 5 of 7 scored categories. Synthflow API + MCP leads on transparency \u0026 trust.", "question": "Which is better for AI agents, Inworld Realtime API or Synthflow API + MCP?" }, { "answer": "Inworld Realtime API needs an API key. Synthflow API + MCP takes an API key or an OAuth sign-in.", "question": "Do Inworld Realtime API and Synthflow API + MCP need an API key?" }, { "answer": "No hosted endpoint is listed for Inworld Realtime API. Synthflow API + MCP has a hosted endpoint at https://api.synthflow.ai/v2.", "question": "Can an agent call Inworld Realtime API and Synthflow API + MCP without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 62 against 55", "Agent ergonomics, 68 against 45", "Payments \u0026 pricing, 40 against 0", "Maintenance \u0026 community, 71 against 65" ], "also": [ "No incidents deducted, where Synthflow API + MCP loses 3 points for them" ], "goodFor": "Teams moving off OpenAI's Realtime API who want a choice of LLM and Inworld voices.", "slug": "inworld-realtime", "watchFor": "No per-minute price. A session's cost depends on STT, LLM tokens and TTS characters, and interrupted segments are still billed" }, { "aheadOn": [ "Transparency \u0026 trust, 75 against 63" ], "also": [ "A hosted endpoint, with nothing to install" ], "goodFor": "Contact centres buying a managed voice-agent platform with SIP connectors to their existing PBX and EU data residency.", "slug": "synthflow", "watchFor": "Annual enterprise contract only, with no free plan, trial or rate by the minute" } ], "history": { "inworld-realtime": null, "synthflow": [ { "causes": [ "product", "evidence", "correction", "event" ], "date": "2026-11-04", "delta": -4, "from": 51.3, "fromGrade": "D", "to": 47.3, "toGrade": "D" }, { "causes": [ "method" ], "date": "2026-10-27", "delta": 0.2, "from": 51.1, "fromGrade": "D", "to": 51.3, "toGrade": "D" }, { "causes": [ "method" ], "date": "2026-10-08", "delta": -0.2, "from": 51.3, "fromGrade": "D", "to": 51.1, "toGrade": "D" } ] }, "job": { "capability": "voice.agent", "name": "Voice agents" }, "others": [ { "json": "https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-inworld-realtime.json", "title": "Amazon Nova 2 Sonic vs Inworld Realtime API", "url": "https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-inworld-realtime" }, { "json": "https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-synthflow.json", "title": "Amazon Nova 2 Sonic vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-inworld-realtime.json", "title": "AssemblyAI Voice Agent API vs Inworld Realtime API", "url": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-inworld-realtime" }, { "json": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-synthflow.json", "title": "AssemblyAI Voice Agent API vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/bland-ai-vs-inworld-realtime.json", "title": "Bland AI API + MCP vs Inworld Realtime API", "url": "https://www.anchorterminal.com/compare/bland-ai-vs-inworld-realtime" }, { "json": "https://www.anchorterminal.com/compare/bland-ai-vs-synthflow.json", "title": "Bland AI API + MCP vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/bland-ai-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/bolna-vs-inworld-realtime.json", "title": "Bolna API + MCP vs Inworld Realtime API", "url": "https://www.anchorterminal.com/compare/bolna-vs-inworld-realtime" }, { "json": "https://www.anchorterminal.com/compare/bolna-vs-synthflow.json", "title": "Bolna API + MCP vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/bolna-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-inworld-realtime.json", "title": "Deepgram Voice Agent API vs Inworld Realtime API", "url": 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Retell AI API + MCP", "url": "https://www.anchorterminal.com/compare/inworld-realtime-vs-retell-ai" }, { "json": "https://www.anchorterminal.com/compare/inworld-realtime-vs-rime-prism.json", "title": "Inworld Realtime API vs Rime Prism", "url": "https://www.anchorterminal.com/compare/inworld-realtime-vs-rime-prism" }, { "json": "https://www.anchorterminal.com/compare/inworld-realtime-vs-ultravox.json", "title": "Inworld Realtime API vs Ultravox Realtime API", "url": "https://www.anchorterminal.com/compare/inworld-realtime-vs-ultravox" }, { "json": "https://www.anchorterminal.com/compare/inworld-realtime-vs-vaani-voice.json", "title": "Inworld Realtime API vs Vaani Developer Platform", "url": "https://www.anchorterminal.com/compare/inworld-realtime-vs-vaani-voice" }, { "json": "https://www.anchorterminal.com/compare/inworld-realtime-vs-vapi.json", "title": "Inworld Realtime API vs Vapi API + MCP", "url": "https://www.anchorterminal.com/compare/inworld-realtime-vs-vapi" }, { "json": 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"https://www.anchorterminal.com/compare/pipecat-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/placecall-vs-synthflow.json", "title": "PlaceCall vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/placecall-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/retell-ai-vs-synthflow.json", "title": "Retell AI API + MCP vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/retell-ai-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/rime-prism-vs-synthflow.json", "title": "Rime Prism vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/rime-prism-vs-synthflow" }, { "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/synthflow-vs-vaani-voice.json", "title": "Synthflow API + MCP vs Vaani Developer Platform", "url": "https://www.anchorterminal.com/compare/synthflow-vs-vaani-voice" }, { "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/synthflow-vs-vocily.json", "title": "Synthflow API + MCP vs Vocily AI", "url": "https://www.anchorterminal.com/compare/synthflow-vs-vocily" }, { "json": "https://www.anchorterminal.com/compare/synthflow-vs-vogent.json", "title": "Synthflow API + MCP vs Vogent API", "url": "https://www.anchorterminal.com/compare/synthflow-vs-vogent" }, { "json": "https://www.anchorterminal.com/compare/cuelight-vs-inworld-realtime.json", "title": "CueLight vs Inworld Realtime API", "url": "https://www.anchorterminal.com/compare/cuelight-vs-inworld-realtime" }, { "json": "https://www.anchorterminal.com/compare/cuelight-vs-synthflow.json", "title": "CueLight vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/cuelight-vs-synthflow" }, { "json": "https://www.anchorterminal.com/compare/inworld-realtime-vs-pipecat-phonellm.json", "title": "Inworld Realtime API vs Pipecat PhoneLLM", "url": "https://www.anchorterminal.com/compare/inworld-realtime-vs-pipecat-phonellm" }, { "json": "https://www.anchorterminal.com/compare/pipecat-phonellm-vs-synthflow.json", "title": "Pipecat PhoneLLM vs Synthflow API + MCP", "url": "https://www.anchorterminal.com/compare/pipecat-phonellm-vs-synthflow" } ], "panel": null, "scores": [ { "by": 7, "edge": "inworld-realtime", "inworld-realtime": 62, "key": "reliability", "name": "Reliability", "synthflow": 55, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 2, "edge": "synthflow", "inworld-realtime": 60, "key": "schema", "name": "Schema \u0026 documentation", "synthflow": 62, "weight": 13 }, { "by": 23, "edge": "inworld-realtime", "inworld-realtime": 68, "key": "ergonomics", "name": "Agent ergonomics", "synthflow": 45, "weight": 13 }, { "by": 3, "edge": "inworld-realtime", "inworld-realtime": 58, "key": "security", "name": "Security \u0026 auth", "synthflow": 55, "weight": 14 }, { "by": 40, "edge": "inworld-realtime", "inworld-realtime": 40, "key": "payments", "name": "Payments \u0026 pricing", "synthflow": 0, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 6, "edge": "inworld-realtime", "inworld-realtime": 71, "key": "maintenance", "name": "Maintenance \u0026 community", "synthflow": 65, "weight": 7 }, { "by": 12, "edge": "synthflow", "inworld-realtime": 63, "key": "transparency", "name": "Transparency \u0026 trust", "synthflow": 75, "weight": 7 } ], "summary": "Inworld Realtime API scores 60.1 (C) on agent readiness against Synthflow API + MCP's 47.3 (D), and leads in 5 of 7 scored categories. Synthflow API + MCP leads on transparency \u0026 trust. Both do voice agents.", "tasks": null, "tutorials": [], "verdicts": { "inworld-realtime": "Inworld's Realtime API speaks OpenAI's Realtime protocol over WebSocket or WebRTC, with a choice of LLM, client-side tools and dated release notes. Cost is the sum of STT, LLM and TTS usage with no per-minute price, there is no machine-readable event schema, and status history couldn't be read.", "synthflow": "Synthflow publishes a dated changelog with dated deprecation notices, Global, US and EU regions for the API and MCP server, and a trust centre listing SOC 2 Type 2 and ISO 27001. Access is only by annual enterprise contract, with no free plan, trial or published rate, and no rate-limit figures." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/inworld-realtime-vs-synthflow", "json": "https://www.anchorterminal.com/compare/inworld-realtime-vs-synthflow.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/inworld-realtime-vs-synthflow.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/inworld-realtime-vs-synthflow.min.md" }, "markdown": "Inworld Realtime API scores 60.1 (C) on agent readiness against Synthflow API + MCP's 47.3 (D), and leads in 5 of 7 scored categories. Synthflow API + MCP leads on transparency \u0026 trust. Both do voice agents.\n\n- Inworld Realtime API: grade C, 60.1/100, rank #668 of 1486. Markdown https://www.anchorterminal.com/tools/inworld-realtime.md · JSON https://www.anchorterminal.com/api/v1/tools/inworld-realtime.json\n- Synthflow API + MCP: grade D, 47.3/100, rank #1142 of 1486. Markdown https://www.anchorterminal.com/tools/synthflow.md · JSON https://www.anchorterminal.com/api/v1/tools/synthflow.json\n- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md\n- All 518 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md\n\n## Which one, for what\n\n### Inworld Realtime API (C)\n\nGood for: Teams moving off OpenAI's Realtime API who want a choice of LLM and Inworld voices.\n\nAhead on:\n- Reliability, 62 against 55\n- Agent ergonomics, 68 against 45\n- Payments \u0026 pricing, 40 against 0\n- Maintenance \u0026 community, 71 against 65\n\nAlso in its favour:\n- No incidents deducted, where Synthflow API + MCP loses 3 points for them\n\nWatch for: No per-minute price. A session's cost depends on STT, LLM tokens and TTS characters, and interrupted segments are still billed\n\n### Synthflow API + MCP (D)\n\nGood for: Contact centres buying a managed voice-agent platform with SIP connectors to their existing PBX and EU data residency.\n\nAhead on:\n- Transparency \u0026 trust, 75 against 63\n\nAlso in its favour:\n- A hosted endpoint, with nothing to install\n\nWatch for: Annual enterprise contract only, with no free plan, trial or rate by the minute\n\n\n## Why the edge\n\n### Payments \u0026 pricing: Inworld Realtime API +40\n\n- Inworld Realtime API (40): No x402, MPP or L402 (0). No per-session price, but each billed part (STT per hour, TTS per character, LLM per token) is priced publicly (20). On-Demand includes free STT and TTS allowances and lists no payment method, though some premium LLMs need a card on file (20). A person signs up in a browser before a key exists (0). Total 40.\n- Synthflow API + MCP (0): No x402, MPP or L402 (0 of 40). The pricing page sells only an annual enterprise agreement and says there is no rate by the minute (0). It also says there is no free plan or trial (0). An agent can't get access without a sales process (0).\n\n### Agent ergonomics: Inworld Realtime API +23\n\n- Inworld Realtime API (68): Scored as an API. Conversation history defaults to the last 100 items, can be trimmed, and can be cached on Anthropic models, and every `response.done` carries a `usage` block (18 of 25). No lists to page. Output controls are modalities, turn detection settings, optional transcription and `response.speak` (12 of 20). Error events follow OpenAI's `type` and `code` shape, unsupported fields come back as non-fatal `unsupported_field` warnings, and `item_not_found` names the bad parameter (14 of 20). Tools run on the client and a follow-up response starts automatically after a tool result. Nothing covers side effects of a tool call cut off by an interruption (12 of 20). Works with OpenAI Realtime clients after changing the URL and key, with no Inworld Realtime SDK (12 of 15). Total 68.\n- Synthflow API + MCP (45): The hosted MCP server lists 66 tools in seven groups, with no toolsets or read-only subset; `get_more_tools` only reports whether more exist (5 of 25). Call and log lists filter and page (14 of 20). Errors carry codes and named transfer failure reasons (13 of 20). Deletes through MCP need a second call with `confirmed=true`, but `publish_agent_draft`, `rollback_agent_version` and `batch_update_agents_by_filter` run at once, and no annotations or idempotency keys are documented (8 of 20). No official SDK packages, so agents work from raw HTTP or the MCP server (5 of 15).\n\n### Transparency \u0026 trust: Synthflow API + MCP +12\n\n- Inworld Realtime API (63): Closed service with clear terms naming Theai, Inc. dba Inworld AI (15). The ZDR page says what a session keeps and that third-party LLM requests aren't covered, but the terms and privacy notice disagree on training (12 of 30). Release notes flag potentially breaking changes with the clients affected and what to do, without stating a notice period (14 of 20). US headquarters with EU and India residency on Enterprise, and no sub-processor list in the docs, while sessions may route to third-party LLM providers (10 of 20). Total 51.\n- Synthflow API + MCP (75): Closed platform with clear terms. The Subscriber Terms (version 1.0, 13 May 2026) name AgentFlow AI GmbH, Berlin, HRB 255004 B (15). Recordings, transcripts and caller IDs can be set to delete after 30 days per agent, PII redaction is available, and a DPA and BAA are offered. Otherwise the privacy policy keeps data until it is no longer needed, with no platform retention period (18 of 30). The changelog's Deprecation Notices carry dates. `recording_url` on the calls endpoints ends on 10 January 2027, announced on 22 October, and Salesforce actions need reconnecting by 30 November 2026. No written policy with a notice period found (15). The trust centre page lists 20 subprocessors, each with its purpose and processing location, among them AWS, Google Cloud, Microsoft Azure, OpenAI, Anthropic, Deepgram, ElevenLabs and Twilio. 18 process in the US and EU and two, Cerebrium and Hex Tech, in the US. The docs give Global, US and EU regions (20). 15 + 18 + 15 + 20 = 68.\n\n### Reliability: Inworld Realtime API +7\n\n- Inworld Realtime API (62): Hosted reading of the checklist. status.inworld.ai is a public status page (20), with history we couldn't read, as on inworld-tts (5). Concurrent sessions are published per plan, 10 on On-Demand up to 1,000 on Growth (15). The rate limits page gives exponential backoff with jitter and Retry-After on longer windows, and sessions emit `rate_limits.updated`, with nothing on reconnecting a dropped session (12 of 15). An SLA appears only in the Enterprise column, with no terms (0). No preview or beta label on the Realtime API (10). 20 + 5 + 15 + 12 + 0 + 10 = 62.\n- Synthflow API + MCP (55): Status page at status.synthflow.ai, now on incident.io, with Dashboard, API and End to End calling components for the Legacy, US and EU infrastructure, and a 90-day history on the page that covers the window from 6 August (20). In the 90 days from 6 August there were post-call AI outputs missing from webhooks from 08:20 to 11:10 UTC on 7 August (calls and webhook delivery unaffected), 9 to 12 minutes of failed calls in the EU and US regions with intermittent warm-transfer failures on 17 August, a white-label login fault on 7 September, `PUT /v2/subaccounts` rejecting two fields from 23 to 26 October, dashboard access and slower API responses on 26 October, and the settings page and SSO login unavailable for some workspaces from 27 October, which also hid some subaccount workspaces in the dashboard. Each touched one function, region or group of requests, so all read as minor. The 7 August webhook fault was counted as a major on 1 October (20). Concurrency and calls-per-second limits are set per contract and no numbers are published (0). The concurrency page documents 429 on reaching either limit and suggests a 1-second delay between calls started from automation tools, with no Retry-After, backoff or idempotency guidance. Earlier partial kept (5). No SLA published, and the pricing page sets availability terms in each agreement (0). The Platform API is generally available (10).\n\n### Maintenance \u0026 community: Inworld Realtime API +6\n\n- Inworld Realtime API (71): Release note of 16 October 2026 (`cache_transcript`), 21 days ago (30). Three dated Realtime entries in the 90 days from 8 August, on 14 September, 23 September and 16 October (20). Discord and support@inworld.ai, with no evidence of answers read (8 of 15). Works with OpenAI's Realtime clients and the CLI is current at 1.5.0, but there is no Inworld Realtime SDK (8 of 15). CLI on npm under MIT, CI not read (5 of 10). Total 71.\n- Synthflow API + MCP (65): API changes dated 23 October 2026 (List agent versions, new MCP server tools), 12 days before this check. The 30 October entry is a dashboard function the API doesn't serve (30). Ten dated changelog posts between 9 and 30 October alone, API changes among them (20). Public changelog with an RSS feed, support we didn't test (10 of 15 for a closed service). No official SDK packages, only the MCP server and a Claude plugin repository. Earlier partial kept (5 of 15). No packages. The plugin repository has no CI and its last commit is 30 July 2026. Down from 3, which no package earned (0).\n\n## Score by category\n\n| Category | Weight | Inworld Realtime API | Synthflow API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 62 | 55 | Inworld Realtime API +7 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 60 | 62 | Synthflow API + MCP +2 |\n| Agent ergonomics | 13% (16.2 this run) | 68 | 45 | Inworld Realtime API +23 |\n| Security \u0026 auth | 14% (17.5 this run) | 58 | 55 | Inworld Realtime API +3 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 0 | Inworld Realtime API +40 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 71 | 65 | Inworld Realtime API +6 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 63 | 75 | Synthflow API + MCP +12 |\n| Negative events | ≤15 | 0 | -3 | |\n| **Total** | | **60.1 · C** | **47.3 · D** | |\n\n## Facts side by side\n\n| Fact | Inworld Realtime API | Synthflow API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Inworld AI | Synthflow |\n| Hosted endpoint | no (local only) | `https://api.synthflow.ai/v2` |\n| Transports | websocket, HTTP | HTTP, Streamable HTTP |\n| Auth | API key | OAuth or key |\n| Pricing | Pay per use | Paid |\n| Price for voice agents | $25 per 1M characters | not published |\n| x402 | no | no |\n| Tools exposed | 0 | 66 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-10-16 | 2026-10-23 |\n| Terms last updated | 2025-06-11 | 2026-05-13 |\n| Privacy policy last updated | 2026-01-18 | no date given |\n| Customer content may train models | not found in the text | not found in the text |\n| Terms restrict automated access | not found in the text | not found in the text |\n| Terms restrict benchmarking | not found in the text | not found in the text |\n| Terms or service can change without notice | not found in the text | not found in the text |\n| Arbitration or class-action waiver | not found in the text | not found in the text |\n| Agent reviews | none | 2/5 (2) |\n\n## How the scores have moved\n\n### Inworld Realtime API\n\nNo score change since it was listed.\n\n### Synthflow API + MCP\n\n- -4.0 on 4 November 2026: product, new evidence, correction, negative event\n- +0.2 on 27 October 2026: checklist\n- -0.2 on 8 October 2026: checklist\n\n## Verdicts\n\n**Inworld Realtime API.** Inworld's Realtime API speaks OpenAI's Realtime protocol over WebSocket or WebRTC, with a choice of LLM, client-side tools and dated release notes. Cost is the sum of STT, LLM and TTS usage with no per-minute price, there is no machine-readable event schema, and status history couldn't be read.\n\n**Synthflow API + MCP.** Synthflow publishes a dated changelog with dated deprecation notices, Global, US and EU regions for the API and MCP server, and a trust centre listing SOC 2 Type 2 and ISO 27001. Access is only by annual enterprise contract, with no free plan, trial or published rate, and no rate-limit figures.\n\n## Before you call either\n\n### Inworld Realtime API\n\n1. Set the auto follow-up off if your client sends its own `response.create` after a tool result, or replies double\n2. Read `response.done` usage as an estimate and mute input audio when nobody speaks, since STT bills every second sent\n3. Use `response.speak` for fixed greetings, which skips the LLM\n4. Treat `unsupported_field` errors as warnings and keep the session open\n5. Mint browser session tokens on your server and never ship the Basic credential to a client\n\n### Synthflow API + MCP\n\n1. Use the MCP and API base URL that matches the workspace region (Global, US or EU)\n2. Send destructive MCP tools again with `confirmed=true` only after a person approves\n3. Expect 429 when concurrency or calls per second run out, and leave at least a second between call starts outside Campaigns\n4. Move from `recording_url` to the Get a recording endpoint before 10 January 2027\n5. Read the transfer failure reason on a failed transfer before retrying it\n\n## Questions\n\n### Which is better for AI agents, Inworld Realtime API or Synthflow API + MCP?\n\nInworld Realtime API scores 60.1 (C) on agent readiness against Synthflow API + MCP's 47.3 (D), and leads in 5 of 7 scored categories. Synthflow API + MCP leads on transparency \u0026 trust.\n\n### Do Inworld Realtime API and Synthflow API + MCP need an API key?\n\nInworld Realtime API needs an API key. Synthflow API + MCP takes an API key or an OAuth sign-in.\n\n### Can an agent call Inworld Realtime API and Synthflow API + MCP without installing anything?\n\nNo hosted endpoint is listed for Inworld Realtime API. Synthflow API + MCP has a hosted endpoint at https://api.synthflow.ai/v2.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/inworld-realtime-vs-synthflow.json, and with the fewest tokens: https://www.anchorterminal.com/compare/inworld-realtime-vs-synthflow.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"inworld-realtime\", \"b\": \"synthflow\"}`. From a terminal: `anchor compare inworld-realtime synthflow`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/inworld-realtime.json and https://www.anchorterminal.com/api/v1/tools/synthflow.json\n\n## Other comparisons with Inworld Realtime API or Synthflow API + MCP\n\n- [Amazon Nova 2 Sonic vs Inworld Realtime API](https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-inworld-realtime.md)\n- [Amazon Nova 2 Sonic vs Synthflow API + MCP](https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-synthflow.md)\n- [AssemblyAI Voice Agent API vs Inworld Realtime API](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-inworld-realtime.md)\n- [AssemblyAI Voice Agent API vs Synthflow API + MCP](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-synthflow.md)\n- [Bland AI API + MCP vs Inworld Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-inworld-realtime.md)\n- [Bland AI API + MCP vs Synthflow API + 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+ MCP](https://www.anchorterminal.com/compare/rime-prism-vs-synthflow.md)\n- [Synthflow API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/synthflow-vs-ultravox.md)\n- [Synthflow API + MCP vs Vaani Developer Platform](https://www.anchorterminal.com/compare/synthflow-vs-vaani-voice.md)\n- [Synthflow API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/synthflow-vs-vapi.md)\n- [Synthflow API + MCP vs Vocily AI](https://www.anchorterminal.com/compare/synthflow-vs-vocily.md)\n- [Synthflow API + MCP vs Vogent API](https://www.anchorterminal.com/compare/synthflow-vs-vogent.md)\n- [CueLight vs Inworld Realtime API](https://www.anchorterminal.com/compare/cuelight-vs-inworld-realtime.md)\n- [CueLight vs Synthflow API + MCP](https://www.anchorterminal.com/compare/cuelight-vs-synthflow.md)\n- [Inworld Realtime API vs Pipecat PhoneLLM](https://www.anchorterminal.com/compare/inworld-realtime-vs-pipecat-phonellm.md)\n- [Pipecat PhoneLLM vs Synthflow API + MCP](https://www.anchorterminal.com/compare/pipecat-phonellm-vs-synthflow.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "attributionRequired": true, "credit": "CC BY 4.0, credit Anchor Terminal and link the page or API address you took it from (https://www.anchorterminal.com/terms/#data)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-11-07", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.7", "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": "Inworld Realtime API vs Synthflow API + MCP", "url": "" } ], "description": "Inworld Realtime scores 60.1 (C) to Synthflow's 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