{ "data": { "a": { "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", "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. Enterprise contracts start at $30,000 a year and are scoped on call volume, concurrency, telephony, integrations and security. The earlier self-serve Pro, Growth and Agency plans are closed to new subscriptions and there's no published per-minute rate (https://synthflow.ai/pricing).", "priceSummary": "Paid", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 support in the docs, pricing page or MCP docs (checked 2026-09-30).", "endpoints": [] }, "toolCount": 60, "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": "2026-10-01", "graded": true, "anchor": { "graded": true, "score": 51.3, "grade": "D", "agentReady": false, "rank": 352, "ranked": true, "rankOf": 452, "categoryRank": 9, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 45, "maintenance": 68, "payments": 0, "reliability": 45, "schema": 87, "security": 51, "transparency": 68 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Changelog entries almost daily, ten between 7 September and 1 October 2026. Sales-led only, contracts from $30,000 a year, no free tier.", "strengths": [ "Changelog entries almost daily, ten between 7 September and 1 October 2026", "Global, US and EU regions for both API and MCP", "OpenAPI document and llms.txt", "Retention toggles, 30-day auto-deletion and PII redaction", "Deletes through MCP need a second confirmed call" ], "weaknesses": [ "Sales-led only, contracts from $30,000 a year, no free tier", "No published per-minute price, concurrency or rate limits", "No official SDK packages", "Post-call webhooks failed for nearly three hours on 7 August 2026", "Publish and rollback through MCP run 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` after a person approves", "Expect 429 on call bursts, since `POST /v2/calls` is limited by calls per second as well as concurrency", "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": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 51.3 } ], "editorialScores": { "ergonomics": 45, "maintenance": 68, "payments": 0, "reliability": 45, "schema": 87, "security": 51, "transparency": 53 }, "provenanceScore": 82 }, "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": "2026-09-30", "score": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/synthflow.json", "live": { "slug": "synthflow", "probe": { "target": "https://api.synthflow.ai/v2", "method": "get", "lastAt": "2026-10-05T00:57:29.013492921Z", "lastOk": true, "lastStatus": 404, "lastMs": 147, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 188, "p95ms24h": 399, "samples24h": 272, "samples30d": 1113, "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": 11, "ok": 11 } ] }, "vendorStatus": { "page": "https://status.synthflow.ai", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-05T00:54:06.169036207Z" }, "githubStars": 0, "securityTxt": { "url": "https://synthflow.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:39.825666303Z" }, "llmsTxt": { "url": "https://docs.synthflow.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:18:17.135484926Z" }, "domain": { "domain": "synthflow.ai", "registered": "2023-07-21", "source": "https://rdap.identitydigital.services/rdap/domain/synthflow.ai", "checkedAt": "2026-10-04T13:05:22.70407658Z" }, "pages": [ { "url": "https://docs.synthflow.ai/changelog", "kind": "changelog", "status": 304, "checkedAt": "2026-10-04T15:44:06.478375762Z", "changedAt": "2026-10-02T15:20:29.611067431Z", "fingerprint": "d9555340c631" }, { "url": "https://synthflow.ai/pricing", "kind": "pricing", "status": 304, "checkedAt": "2026-10-04T15:48:18.850561804Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "63e74a7a5acd" }, { "url": "https://docs.synthflow.ai/privacy-policy", "kind": "privacy", "status": 304, "checkedAt": "2026-10-04T15:44:09.424908736Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "efaf26369f90" }, { "url": "https://docs.synthflow.ai/terms-conditions", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:44:11.249829924Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "3ed62f6822c3" } ], "updatedAt": "2026-10-05T00:57:29.013492921Z" } }, "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": 63.7, "grade": "B", "agentReady": false, "rank": 198, "ranked": true, "rankOf": 452, "categoryRank": 5, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 64, "maintenance": 88, "payments": 35, "reliability": 70, "schema": 89, "security": 58, "transparency": 76 }, "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.", "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": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 63.7 } ], "editorialScores": { "ergonomics": 64, "maintenance": 88, "payments": 35, "reliability": 70, "schema": 89, "security": 58, "transparency": 70 }, "provenanceScore": 82 }, "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": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/vapi.json", "live": { "slug": "vapi", "probe": { "target": "https://api.vapi.ai", "method": "get", "lastAt": "2026-10-05T00:57:30.092583865Z", "lastOk": true, "lastStatus": 200, "lastMs": 207, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 190, "p95ms24h": 551, "samples24h": 272, "samples30d": 1113, "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": 11, "ok": 11 } ] }, "vendorStatus": { "page": "https://status.vapi.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-04T21:40:32.91562276Z" }, "versions": [ { "registry": "github", "name": "VapiAI/mcp-server", "version": "v0.0.11", "released": "2026-08-14", "seenAt": "2026-10-04T16:43:12.477208468Z" }, { "registry": "npm", "name": "@vapi-ai/mcp-server", "version": "0.0.11", "seenAt": "2026-10-04T16:43:10.657227109Z" }, { "registry": "npm", "name": "@vapi-ai/server-sdk", "version": "2.0.1", "seenAt": "2026-10-04T16:43:06.847289486Z" }, { "registry": "npm", "name": "@vapi-ai/web", "version": "2.7.1", "seenAt": "2026-10-04T16:43:09.259416721Z" }, { "registry": "pypi", "name": "vapi_server_sdk", "version": "1.11.1", "released": "2026-05-20", "seenAt": "2026-10-04T16:43:10.468923211Z" } ], "githubStars": 57, "npmWeekly": 205182, "pypiWeekly": 39699, "securityTxt": { "url": "https://vapi.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:46.43020372Z" }, "llmsTxt": { "url": "https://docs.vapi.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:18:23.657652287Z" }, "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": 200, "checkedAt": "2026-10-04T15:44:13.606342765Z", "changedAt": "2026-10-03T15:32:20.588337898Z", "fingerprint": "ec991822798a" }, { "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": 200, "checkedAt": "2026-10-04T15:44:25.802628589Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "9f62a32477a4" }, { "url": "https://vapi.ai/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-04T15:48:41.681772611Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "f3c0afec077f" }, { "url": "https://vapi.ai/privacy", "kind": "privacy", "status": 304, "checkedAt": "2026-10-04T15:48:43.888276245Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "f13594373bcf" }, { "url": "https://vapi.ai/terms-of-service", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:48:45.895499196Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "4b1fd29445f7" } ], "updatedAt": "2026-10-05T00:57:30.092583865Z" } }, "summary": "Vapi API + MCP has a score of 63.7 (B) against Synthflow API + MCP's 51.3 (D). Both do voice agent. The largest gap is payments \u0026 pricing, 35 points." }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/synthflow-vs-vapi", "json": "https://www.anchorterminal.com/compare/synthflow-vs-vapi.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/synthflow-vs-vapi.md", "slim": "https://www.anchorterminal.com/compare/synthflow-vs-vapi.min.md" }, "markdown": "Vapi API + MCP has a score of 63.7 (B) against Synthflow API + MCP's 51.3 (D). Both do voice agent. The largest gap is payments \u0026 pricing, 35 points.\n\n- Synthflow API + MCP: grade D, 51.3/100, rank #352 of 452. Markdown https://www.anchorterminal.com/tools/synthflow.md · JSON https://www.anchorterminal.com/api/v1/tools/synthflow.json\n- Vapi API + MCP: grade B, 63.7/100, rank #198 of 452. Markdown https://www.anchorterminal.com/tools/vapi.md · JSON https://www.anchorterminal.com/api/v1/tools/vapi.json\n\n## Which one, for what\n\nPick Synthflow API + MCP for nothing in particular (no category where it leads by five points or more).\n\nPick Vapi API + MCP for reliability (+25), agent ergonomics (+19), security \u0026 auth (+7), payments \u0026 pricing (+35), maintenance \u0026 community (+20), transparency \u0026 trust (+8).\n\n## Score by category\n\n| Category | Weight | Synthflow API + MCP | Vapi API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 45 | 70 | Vapi API + MCP +25 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 87 | 89 | Vapi API + MCP +2 |\n| Agent ergonomics | 13% (16.2 this run) | 45 | 64 | Vapi API + MCP +19 |\n| Security \u0026 auth | 14% (17.5 this run) | 51 | 58 | Vapi API + MCP +7 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 0 | 35 | Vapi API + MCP +35 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 68 | 88 | Vapi API + MCP +20 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 68 | 76 | Vapi API + MCP +8 |\n| Negative events | ≤15 | 0 | -4 | |\n| **Total** | | **51.3 · D** | **63.7 · B** | |\n\n## Facts side by side\n\n| Fact | Synthflow API + MCP | Vapi API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Synthflow | Vapi |\n| Hosted endpoint | `https://api.synthflow.ai/v2` | `https://api.vapi.ai` |\n| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP, stdio |\n| Auth | OAuth or key | API key |\n| Pricing | Paid | Pay per use |\n| x402 | no | no |\n| Licence | none | MIT (MCP server) |\n| Tools exposed | 60 | 20 |\n| Context cost (tools/list) | n/a | n/a |\n| p95 latency | not measured yet | not measured yet |\n| Availability (30d) | not measured yet | not measured yet |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| MCP registry | not listed | not listed |\n| Last release | 2026-10-01 | 2026-09-21 |\n| Popularity | none | 57 stars, 177k npm/wk, 42k PyPI/wk |\n| Agent reviews | 2/5 (2) | 2.5/5 (2) |\n\n## Verdicts\n\n**Synthflow API + MCP.** Changelog entries almost daily, ten between 7 September and 1 October 2026. Sales-led only, contracts from $30,000 a year, no free tier.\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### 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` after a person approves\n3. Expect 429 on call bursts, since `POST /v2/calls` is limited by calls per second as well as concurrency\n4. Read the transfer failure reason on a failed transfer before retrying it\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## Other comparisons with Synthflow API + MCP or Vapi API + MCP\n\n- [Bland AI API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/bland-ai-vs-synthflow.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 Synthflow API + MCP](https://www.anchorterminal.com/compare/bolna-vs-synthflow.md)\n- [Bolna API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/bolna-vs-vapi.md)\n- [Deepgram Voice Agent API vs Synthflow API + MCP](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-synthflow.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 Synthflow API + MCP](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-synthflow.md)\n- [ElevenLabs Agents API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-vapi.md)\n- [Hume EVI (Empathic Voice Interface) vs Synthflow API + MCP](https://www.anchorterminal.com/compare/hume-evi-vs-synthflow.md)\n- [Hume EVI (Empathic Voice Interface) vs Vapi API + MCP](https://www.anchorterminal.com/compare/hume-evi-vs-vapi.md)\n- [Retell AI API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/retell-ai-vs-synthflow.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 Ultravox Realtime API](https://www.anchorterminal.com/compare/synthflow-vs-ultravox.md)\n- [Synthflow API + MCP vs Vogent API](https://www.anchorterminal.com/compare/synthflow-vs-vogent.md)\n- [Ultravox Realtime API vs Vapi API + MCP](https://www.anchorterminal.com/compare/ultravox-vs-vapi.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": "2026-10-05", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.3", "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": "Synthflow API + MCP vs Vapi API + MCP", "url": "" } ], "description": "Vapi API + MCP has a score of 63.7 (B) against Synthflow API + MCP's 51.3 (D). Both do voice agent. The largest gap is payments \u0026 pricing, 35 points. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Synthflow API + MCP D 51.3", "Vapi API + MCP B 63.7", "scores" ], "h1": "Synthflow API + MCP vs Vapi API + MCP", "image": "https://www.anchorterminal.com/assets/og/compare-synthflow-vs-vapi.png", "path": "/compare/synthflow-vs-vapi", "published": "2026-10-01", "section": "tools", "title": "Synthflow API + MCP vs Vapi API + MCP for AI agents, D 51.3 vs B 63.7", "toc": null, "updated": "2026-10-05", "url": "https://www.anchorterminal.com/compare/synthflow-vs-vapi" }, "tokens": { "markdown": 1600, "slim": 380 }, "version": 1 }