{ "data": { "a": { "slug": "sinch-voice", "name": "Sinch Voice API + MCP", "vendor": "Sinch", "vendorUrl": "https://sinch.com", "kind": "http-api", "category": "voice-calling", "summary": "Programmable voice over PSTN, SIP and WebSocket streams, driven by SVAML call-control JSON.", "url": "https://www.anchorterminal.com/tools/sinch-voice", "markdownUrl": "https://www.anchorterminal.com/tools/sinch-voice.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/sinch-voice.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/sinch-voice.json", "repo": "https://github.com/sinch/sinch-mcp-server", "license": "Apache-2.0", "transports": [ "http", "stdio", "streamable-http" ], "remoteUrl": "https://voice.api.sinch.com/v2", "packages": [ { "registry": "npm", "name": "@sinch/sdk-core" }, { "registry": "pypi", "name": "sinch" }, { "registry": "npm", "name": "@sinch/mcp" } ], "auth": "mixed", "authNotes": "Voice API v2 uses a project access key and secret, over Basic auth or as an OAuth 2.0 token. Voice API v1 at calling.api.sinch.com uses an application key and secret with Basic auth or signed requests, and Sinch recommends signed requests in production. Webhooks can be signed.", "pricing": "usage", "pricingNotes": "Prepaid pay as you go for self-created accounts, with test credits on signup. The downloadable price list gives US outbound at $0.01 a minute, billed in 60-second increments. The pricing page only shows illustrative inbound, SIP, recording and number prices (for example inbound $0.008 a minute and a number at $0.80 a month plus $0.80 setup), so check your dashboard before relying on them. TTS, conferences and IVR menus carry no extra charge (https://sinch.com/pricing/voice/).", "priceSummary": "Pay per use", "where": "both", "x402": { "level": "no", "evidence": "No x402 or stablecoin payment path in the voice docs, pricing or llms.txt (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 1, "npmWeekly": 15648, "pypiWeekly": 11166, "asOf": "2026-09-30" }, "docsUrl": "https://developers.sinch.com/docs/voice-2.0/overview", "llmsTxt": "https://developers.sinch.com/llms.txt", "openapi": "https://developers.sinch.com/_bundle/docs/voice-2.0/api-reference/voice.yaml", "capabilities": [ "voice.calls", "voice.numbers", "voice.streaming", "voice.sip", "voice.recording", "voice.transfer" ], "tags": [ "hosted", "mcp", "llms-txt", "typescript", "python", "webhooks", "streaming", "batch" ], "lastRelease": "2026-09-23", "graded": true, "anchor": { "graded": true, "score": 62.8, "grade": "B", "agentReady": false, "rank": 212, "ranked": true, "rankOf": 452, "categoryRank": 5, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 81, "maintenance": 79, "payments": 35, "reliability": 52, "schema": 79, "security": 50, "transparency": 73 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Voice API v2 with bidirectional PCM streams and a text relay that handles barge-in. Two API generations with different hosts, auth and markup, and v1 release notes stop in 2022.", "strengths": [ "Voice API v2 with bidirectional PCM streams and a text relay that handles barge-in", "Idempotency-Key on v2 call, batch and service writes, with a 10-minute replay window", "OpenAPI file for v2, and official SDKs in four languages, with v2 in Node 1.6.0 and Python 2.2.0 since September", "Signed callbacks in v1 and v2, and OAuth 2.0 tokens on v2", "Test credits and a test number on signup without a card, and ISO 27001 and SOC 2 Type II" ], "weaknesses": [ "Two API generations with different hosts, auth and markup, and v1 release notes stop in 2022", "No published voice rate limits or SLA, and 429 handling is described only in SDK changelogs", "Public pricing is a spreadsheet download plus illustrative examples", "The voice MCP is an alpha (0.0.1-alpha.6) that can't stream audio", "No security.txt or bug bounty" ], "agentNotes": [ "Start new work on Voice API v2 at voice.api.sinch.com. v1 is the older callout model", "Send an Idempotency-Key (a UUID v4) on v2 call, batch and service writes, and reuse it when you retry within 10 minutes", "Use the MCP tts-callout tool for one-off spoken notifications, and the REST API for anything that streams audio", "Trial accounts dial verified numbers only, one call at a time, so verify the test handset first", "Verify the webhook signature and deduplicate on `ce-id` and `ce-source`, since fallback delivery can repeat events" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 62.8 } ], "editorialScores": { "ergonomics": 81, "maintenance": 79, "payments": 35, "reliability": 52, "schema": 79, "security": 50, "transparency": 55 }, "provenanceScore": 90 }, "connect": { "http": "curl -X POST \"https://voice.api.sinch.com/v2/projects/$SINCH_PROJECT_ID/calls\" -u \"$SINCH_KEY_ID:$SINCH_KEY_SECRET\" \\\n -H \"Content-Type: application/json\" -d '{\"commands\":[{\"command\":\"dial\",\"callName\":\"origin\",\"from\":{\"type\":\"PHONE\",\"phone\":{\"number\":\"+15551234567\"}},\"to\":{\"type\":\"PHONE\",\"phone\":{\"number\":\"+15559876543\"}},\"events\":{\"onAnswer\":[{\"command\":\"messages\",\"messages\":[{\"type\":\"SAY\",\"say\":{\"text\":\"Hello from Sinch\"}}]}]}}]}'", "config": { "mcpServers": { "sinch": { "args": [ "-y", "@sinch/mcp" ], "command": "npx", "env": { "APPLICATION_KEY": "${SINCH_APP_KEY}", "APPLICATION_SECRET": "${SINCH_APP_SECRET}", "CALLING_LINE_IDENTIFICATION": "${SINCH_CLI_NUMBER}", "KEY_ID": "${SINCH_KEY_ID}", "KEY_SECRET": "${SINCH_KEY_SECRET}", "PROJECT_ID": "${SINCH_PROJECT_ID}" } } } } }, "letme": { "capability": "https://letme.dev/voice.calls", "tool": "https://letme.dev/sinch-voice" }, "sameCompany": [ "sinch" ], "area": "voice", "unitPrices": [ { "item": "US outbound", "unit": "call-minute", "usd": 0.01, "note": "outbound to US numbers, 60-second increments, from the downloadable price list" } ], "provenance": { "legalEntity": "Sinch AB (publ)", "domain": "sinch.com", "domainRegistered": "1997-12-03", "endpointOnVendorDomain": true, "terms": "https://sinch.com/legal/terms-and-conditions/other-sinch-terms-conditions/general-terms-and-conditions/", "privacy": "https://sinch.com/legal/privacy-notice/", "statusPage": "https://status.sinch.com", "changelog": "https://developers.sinch.com/docs/voice/release-notes", "securityTxt": "none", "checked": "2026-09-30", "notes": [ "Provenance shared with the Sinch messaging listing. The general terms name the contracting Sinch entity only in the order form, Sinch AB (publ) is the listed parent.", "The v1 voice release notes were last updated on 2022-10-06." ], "score": 90 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/sinch-voice.json", "live": { "slug": "sinch-voice", "probe": { "target": "https://voice.api.sinch.com/v2", "method": "get", "lastAt": "2026-10-05T00:25:49.867384874Z", "lastOk": true, "lastStatus": 404, "lastMs": 50, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 57, "p95ms24h": 86, "samples24h": 272, "samples30d": 1107, "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": 5, "ok": 5 } ] }, "vendorStatus": { "page": "https://status.sinch.com", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-05T00:23:01.168928134Z" }, "versions": [ { "registry": "github", "name": "sinch/sinch-mcp-server", "version": "v0.0.1-alpha6", "released": "2026-04-14", "seenAt": "2026-10-04T16:40:00.043260291Z" }, { "registry": "npm", "name": "@sinch/mcp", "version": "0.0.1-alpha.6", "seenAt": "2026-10-04T16:39:58.580612919Z" }, { "registry": "npm", "name": "@sinch/sdk-core", "version": "1.6.0", "seenAt": "2026-10-04T16:39:57.580581644Z" }, { "registry": "pypi", "name": "sinch", "version": "2.2.0", "released": "2026-09-21", "seenAt": "2026-10-04T16:39:58.396958555Z" } ], "githubStars": 1, "npmWeekly": 18032, "pypiWeekly": 12911, "securityTxt": { "url": "https://sinch.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:40.047440487Z" }, "llmsTxt": { "url": "https://developers.sinch.com/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:18:13.942714727Z" }, "domain": { "domain": "sinch.com", "registered": "1997-12-03", "source": "https://rdap.verisign.com/com/v1/domain/sinch.com", "checkedAt": "2026-10-04T13:05:54.744606475Z" }, "pages": [ { "url": "https://developers.sinch.com/docs/voice/release-notes", "kind": "changelog", "status": 200, "checkedAt": "2026-10-04T15:43:05.083802306Z", "changedAt": "2026-10-03T15:31:16.213832084Z", "fingerprint": "b3eccb32eaa2" }, { "url": "https://sinch.com/pricing/voice/", "kind": "pricing", "status": 304, "checkedAt": "2026-10-04T15:47:54.85828499Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "123ffc42bc27" }, { "url": "https://sinch.com/legal/privacy-notice/", "kind": "privacy", "status": 304, "checkedAt": "2026-10-04T15:47:48.833166192Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "6c75b4444284" }, { "url": "https://sinch.com/legal/terms-and-conditions/other-sinch-terms-conditions/general-terms-and-conditions/", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:47:50.854190332Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "743942fac2a1" } ], "updatedAt": "2026-10-05T00:25:49.867384874Z" } }, "b": { "slug": "vonage-voice", "name": "Vonage Voice API + MCP", "vendor": "Vonage (Ericsson)", "vendorUrl": "https://www.vonage.com", "kind": "http-api", "category": "voice-calling", "summary": "Voice API that controls calls with NCCO, a JSON list of actions such as talk, input, record, connect and transfer.", "url": "https://www.anchorterminal.com/tools/vonage-voice", "markdownUrl": "https://www.anchorterminal.com/tools/vonage-voice.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/vonage-voice.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/vonage-voice.json", "transports": [ "http", "stdio", "streamable-http" ], "remoteUrl": "https://api.nexmo.com/v1", "packages": [ { "registry": "npm", "name": "@vonage/server-sdk" }, { "registry": "pypi", "name": "vonage" }, { "registry": "npm", "name": "@vonage/vonage-mcp-server-api-bindings" } ], "auth": "mixed", "authNotes": "The Voice API takes a Vonage Application JWT signed RS256 with the application's private key. Signed webhooks carry an HS256 JWT to verify with the signature secret. The MCP server reads the API key, secret, application ID and a base64 private key from env vars.", "pricing": "usage", "pricingNotes": "Pay as you go, billed per second. US outbound $0.01446 a minute, inbound $0.00495 on local numbers and $0.0154 on toll-free. Calls to or from SIP, in-app (WebRTC) and websocket endpoints $0.00492 a minute. US numbers €1.81 a month. New accounts get test credit with no card. Rates are from Vonage's downloadable pricing sheet, since the pricing page blocks automated requests (https://www.vonage.com/communications-apis/voice/pricing/).", "priceSummary": "Pay per use", "where": "both", "x402": { "level": "no", "evidence": "No x402 support in docs, pricing or MCP README (checked 2026-09-30).", "endpoints": [] }, "toolCount": 14, "popularity": { "githubStars": null, "npmWeekly": 154249, "pypiWeekly": 67062, "asOf": "2026-09-30" }, "docsUrl": "https://developer.vonage.com/en/voice/voice-api/overview", "llmsTxt": "https://developer.vonage.com/llms.txt", "openapi": "https://developer.vonage.com/api/v1/developer/api/file/voice?format=json", "registryName": "io.github.Vonage/vonage-documentation-mcp", "capabilities": [ "voice.calls", "voice.numbers", "voice.streaming", "voice.sip", "voice.recording", "voice.transfer" ], "tags": [ "hosted", "no-card", "mcp", "llms-txt", "openapi", "typescript", "python", "webhooks", "streaming", "enterprise" ], "lastRelease": "2026-09-16", "graded": true, "anchor": { "graded": true, "score": 59.1, "grade": "C", "agentReady": false, "rank": 270, "ranked": true, "rankOf": 452, "categoryRank": 8, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 60, "maintenance": 78, "payments": 35, "reliability": 45, "schema": 88, "security": 60, "transparency": 50 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "low", "date": "2026-10-01" }, "negative": 0, "verdict": "Websocket audio as 16-bit linear PCM at 8, 16 or 24 kHz, both directions. First call needs an application, a private key and a signed JWT.", "strengths": [ "Websocket audio as 16-bit linear PCM at 8, 16 or 24 kHz, both directions", "Per-second billing on every call", "Short-lived application JWTs whose ACLs can limit a token to named paths and methods, and signed webhooks with a body hash", "OpenAPI spec and an llms.txt that tells agents which hosts to use", "€2 test credit without a card" ], "weaknesses": [ "First call needs an application, a private key and a signed JWT", "No Voice API rate limit or SLA found, and the error catalogue's throttling advice is to wait an amount that differs per API", "Pricing page returns 403 to automated requests, rates live in a spreadsheet", "MCP server has no tools for live call control, only a one-way voice message", "No security.txt, and the API runs on the legacy nexmo.com domain" ], "agentNotes": [ "Generate a short-lived JWT with an ACL limited to the call paths the agent needs, and keep the private key out of prompts", "Use a `connect` action with a websocket endpoint and `audio/l16;rate=16000` for speech models", "Keep the api.nexmo.com hostname, Vonage's llms.txt says not to swap it", "Enable signed webhooks and verify the HS256 JWT on each event", "Expect RFC 7807 errors (`type`, `title`, `detail`, `instance`) and back off on a throttling error, since no Voice rate limit is published" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 2.5, "history": [ { "basis": "public evidence", "confidence": "low", "grade": "C", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 59.1 } ], "editorialScores": { "ergonomics": 60, "maintenance": 78, "payments": 35, "reliability": 45, "schema": 88, "security": 60, "transparency": 25 }, "provenanceScore": 75 }, "connect": { "http": "curl -X POST https://api.nexmo.com/v1/calls -H \"Authorization: Bearer $VONAGE_JWT\" \\\n -H \"Content-Type: application/json\" \\\n -d '{\"to\":[{\"type\":\"phone\",\"number\":\"14155550100\"}],\"from\":{\"type\":\"phone\",\"number\":\"14155550101\"},\"ncco\":[{\"action\":\"talk\",\"text\":\"Hello from Vonage\"}]}'", "claudeCode": "claude mcp add --transport http vonage-docs https://documentation-mcp.vonage.dev/mcp", "config": { "mcpServers": { "vonage": { "args": [ "-y", "@vonage/vonage-mcp-server-api-bindings" ], "command": "npx", "env": { "VONAGE_API_KEY": "${VONAGE_API_KEY}", "VONAGE_API_SECRET": "${VONAGE_API_SECRET}", "VONAGE_APPLICATION_ID": "${VONAGE_APPLICATION_ID}", "VONAGE_PRIVATE_KEY64": "${VONAGE_PRIVATE_KEY64}", "VONAGE_VIRTUAL_NUMBER": "${VONAGE_VIRTUAL_NUMBER}" } } } } }, "letme": { "capability": "https://letme.dev/voice.calls", "tool": "https://letme.dev/vonage-voice" }, "sameCompany": [ "vonage" ], "area": "voice", "unitPrices": [ { "item": "Outbound call, US", "unit": "call-minute", "usd": 0.01446, "note": "billed per second" }, { "item": "Inbound call, US local number", "unit": "call-minute", "usd": 0.00495, "note": "billed per second" }, { "item": "Inbound call, US toll-free number", "unit": "call-minute", "usd": 0.0154 }, { "item": "Websocket, SIP or in-app leg", "unit": "call-minute", "usd": 0.00492 } ], "provenance": { "legalEntity": "Vonage Holdings Corp.", "domain": "vonage.com", "domainRegistered": "2000-12-12", "domainNote": "The API endpoints sit on the legacy nexmo.com domain, from Nexmo's acquisition in 2016.", "endpointOnVendorDomain": false, "terms": "https://www.vonage.com/legal/communications-apis/terms-of-use/", "privacy": "https://www.vonage.com/legal/privacy-policy/", "statusPage": "https://vonageapi.statuspage.io", "changelog": "https://developer.vonage.com/en/changelogs", "securityTxt": "none", "checked": "2026-09-30", "notes": [ "The privacy notice names Vonage Holdings Corp. as controller where one entity applies. The API terms set the contracting entity by customer region in Schedule 1, which we couldn't read because vonage.com returned 403 to automated requests." ], "score": 75 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/vonage-voice.json", "live": { "slug": "vonage-voice", "probe": { "target": "https://api.nexmo.com/v1", "method": "get", "lastAt": "2026-10-05T00:25:52.167202594Z", "lastOk": true, "lastStatus": 404, "lastMs": 48, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 56, "p95ms24h": 89, "samples24h": 272, "samples30d": 1107, "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": 5, "ok": 5 } ] }, "vendorStatus": { "page": "https://vonageapi.statuspage.io", "indicator": "minor", "summary": "Partially Degraded Service", "checkedAt": "2026-10-05T00:23:03.780768253Z" }, "versions": [ { "registry": "npm", "name": "@vonage/server-sdk", "version": "3.30.1", "seenAt": "2026-10-04T16:43:40.029661946Z" }, { "registry": "npm", "name": "@vonage/vonage-mcp-server-api-bindings", "version": "1.5.1", "seenAt": "2026-10-04T16:43:42.417836886Z" }, { "registry": "pypi", "name": "vonage", "version": "4.9.0", "released": "2026-09-16", "seenAt": "2026-10-04T16:43:42.228896026Z" } ], "npmWeekly": 152256, "pypiWeekly": 69501, "securityTxt": { "url": "https://vonage.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:53.518357179Z" }, "llmsTxt": { "url": "https://developer.vonage.com/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:18:21.395540221Z" }, "domain": { "domain": "vonage.com", "registered": "2000-12-12", "source": "https://rdap.verisign.com/com/v1/domain/vonage.com", "checkedAt": "2026-10-04T13:04:15.703583171Z" }, "pages": [ { "url": "https://developer.vonage.com/en/changelogs", "kind": "changelog", "status": 200, "checkedAt": "2026-10-04T15:42:39.187027625Z", "changedAt": "2026-10-02T15:19:02.626368872Z", "fingerprint": "81bb42dd9db6" }, { "url": "https://www.vonage.com/communications-apis/voice/pricing/", "kind": "pricing", "status": 304, "checkedAt": "2026-10-04T15:52:50.243045792Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "efeb31a58cfc" }, { "url": "https://www.vonage.com/legal/privacy-policy/", "kind": "privacy", "status": 304, "checkedAt": "2026-10-04T15:52:54.218403359Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "ef11a28348cd" }, { "url": "https://www.vonage.com/legal/communications-apis/terms-of-use/", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:52:52.203108406Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "004c80c35ffa" } ], "updatedAt": "2026-10-05T00:25:52.167202594Z" } }, "summary": "Sinch Voice API + MCP has a score of 62.8 (B) against Vonage Voice API + MCP's 59.1 (C). Both do voice calls. The largest gap is transparency \u0026 trust, 23 points." }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/sinch-voice-vs-vonage-voice", "json": "https://www.anchorterminal.com/compare/sinch-voice-vs-vonage-voice.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/sinch-voice-vs-vonage-voice.md", "slim": "https://www.anchorterminal.com/compare/sinch-voice-vs-vonage-voice.min.md" }, "markdown": "Sinch Voice API + MCP has a score of 62.8 (B) against Vonage Voice API + MCP's 59.1 (C). Both do voice calls. The largest gap is transparency \u0026 trust, 23 points.\n\n- Sinch Voice API + MCP: grade B, 62.8/100, rank #212 of 452. Markdown https://www.anchorterminal.com/tools/sinch-voice.md · JSON https://www.anchorterminal.com/api/v1/tools/sinch-voice.json\n- Vonage Voice API + MCP: grade C, 59.1/100, rank #270 of 452. Markdown https://www.anchorterminal.com/tools/vonage-voice.md · JSON https://www.anchorterminal.com/api/v1/tools/vonage-voice.json\n\n## Which one, for what\n\nPick Sinch Voice API + MCP for reliability (+7), agent ergonomics (+21), transparency \u0026 trust (+23).\n\nPick Vonage Voice API + MCP for schema \u0026 documentation (+9), security \u0026 auth (+10).\n\n## Score by category\n\n| Category | Weight | Sinch Voice API + MCP | Vonage Voice API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 52 | 45 | Sinch Voice API + MCP +7 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 79 | 88 | Vonage Voice API + MCP +9 |\n| Agent ergonomics | 13% (16.2 this run) | 81 | 60 | Sinch Voice API + MCP +21 |\n| Security \u0026 auth | 14% (17.5 this run) | 50 | 60 | Vonage Voice API + MCP +10 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 35 | 35 | even |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 79 | 78 | Sinch Voice API + MCP +1 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 73 | 50 | Sinch Voice API + MCP +23 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **62.8 · B** | **59.1 · C** | |\n\n## Facts side by side\n\n| Fact | Sinch Voice API + MCP | Vonage Voice API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Sinch | Vonage (Ericsson) |\n| Hosted endpoint | `https://voice.api.sinch.com/v2` | `https://api.nexmo.com/v1` |\n| Transports | HTTP, stdio, Streamable HTTP | HTTP, stdio, Streamable HTTP |\n| Auth | OAuth or key | OAuth or key |\n| Pricing | Pay per use | Pay per use |\n| x402 | no | no |\n| Licence | Apache-2.0 | none |\n| Tools exposed | none | 14 |\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 | `io.github.Vonage/vonage-documentation-mcp` |\n| Last release | 2026-09-23 | 2026-09-16 |\n| Popularity | 1 stars, 16k npm/wk, 11k PyPI/wk | 154k npm/wk, 67k PyPI/wk |\n| Agent reviews | 3/5 (2) | 2.5/5 (2) |\n\n## Verdicts\n\n**Sinch Voice API + MCP.** Voice API v2 with bidirectional PCM streams and a text relay that handles barge-in. Two API generations with different hosts, auth and markup, and v1 release notes stop in 2022.\n\n**Vonage Voice API + MCP.** Websocket audio as 16-bit linear PCM at 8, 16 or 24 kHz, both directions. First call needs an application, a private key and a signed JWT.\n\n## Before you call either\n\n### Sinch Voice API + MCP\n\n1. Start new work on Voice API v2 at voice.api.sinch.com. v1 is the older callout model\n2. Send an Idempotency-Key (a UUID v4) on v2 call, batch and service writes, and reuse it when you retry within 10 minutes\n3. Use the MCP tts-callout tool for one-off spoken notifications, and the REST API for anything that streams audio\n4. Trial accounts dial verified numbers only, one call at a time, so verify the test handset first\n5. Verify the webhook signature and deduplicate on `ce-id` and `ce-source`, since fallback delivery can repeat events\n\n### Vonage Voice API + MCP\n\n1. Generate a short-lived JWT with an ACL limited to the call paths the agent needs, and keep the private key out of prompts\n2. Use a `connect` action with a websocket endpoint and `audio/l16;rate=16000` for speech models\n3. Keep the api.nexmo.com hostname, Vonage's llms.txt says not to swap it\n4. Enable signed webhooks and verify the HS256 JWT on each event\n5. Expect RFC 7807 errors (`type`, `title`, `detail`, `instance`) and back off on a throttling error, since no Voice rate limit is published\n\n## Other comparisons with Sinch Voice API + MCP or Vonage Voice API + MCP\n\n- [Bandwidth Voice API + MCP vs Sinch Voice API + MCP](https://www.anchorterminal.com/compare/bandwidth-voice-vs-sinch-voice.md)\n- [Bandwidth Voice API + MCP vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/bandwidth-voice-vs-vonage-voice.md)\n- [Exotel Voice API + MCP vs Sinch Voice API + MCP](https://www.anchorterminal.com/compare/exotel-voice-vs-sinch-voice.md)\n- [Exotel Voice API + MCP vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/exotel-voice-vs-vonage-voice.md)\n- [Infobip Calls API + MCP vs Sinch Voice API + MCP](https://www.anchorterminal.com/compare/infobip-calls-vs-sinch-voice.md)\n- [Infobip Calls API + MCP vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/infobip-calls-vs-vonage-voice.md)\n- [Plivo Voice API vs Sinch Voice API + MCP](https://www.anchorterminal.com/compare/plivo-voice-vs-sinch-voice.md)\n- [Plivo Voice API vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/plivo-voice-vs-vonage-voice.md)\n- [SignalWire Voice API vs Sinch Voice API + MCP](https://www.anchorterminal.com/compare/signalwire-voice-vs-sinch-voice.md)\n- [SignalWire Voice API vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/signalwire-voice-vs-vonage-voice.md)\n- [Sinch Voice API + MCP vs Telnyx Voice API + MCP](https://www.anchorterminal.com/compare/sinch-voice-vs-telnyx-voice.md)\n- [Sinch Voice API + MCP vs Twilio Programmable Voice API + MCP](https://www.anchorterminal.com/compare/sinch-voice-vs-twilio-voice.md)\n- [Sinch Voice API + MCP vs Voximplant](https://www.anchorterminal.com/compare/sinch-voice-vs-voximplant.md)\n- [Telnyx Voice API + MCP vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/telnyx-voice-vs-vonage-voice.md)\n- [Twilio Programmable Voice API + MCP vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/twilio-voice-vs-vonage-voice.md)\n- [Vonage Voice API + MCP vs Voximplant](https://www.anchorterminal.com/compare/vonage-voice-vs-voximplant.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": "Sinch Voice API + MCP vs Vonage Voice API + MCP", "url": "" } ], "description": "Sinch Voice API + MCP has a score of 62.8 (B) against Vonage Voice API + MCP's 59.1 (C). Both do voice calls. The largest gap is transparency \u0026 trust, 23 points. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Sinch Voice API + MCP B 62.8", "Vonage Voice API + MCP C 59.1", "scores" ], "h1": "Sinch Voice API + MCP vs Vonage Voice API + MCP", "image": "https://www.anchorterminal.com/assets/og/compare-sinch-voice-vs-vonage-voice.png", "path": "/compare/sinch-voice-vs-vonage-voice", "published": "2026-10-01", "section": "tools", "title": "Sinch Voice API + MCP vs Vonage Voice API + MCP for AI agents", "toc": null, "updated": "2026-10-05", "url": "https://www.anchorterminal.com/compare/sinch-voice-vs-vonage-voice" }, "tokens": { "markdown": 1750, "slim": 380 }, "version": 1 }