{
  "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": "2026-10-04T23:48:15.890085803Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 63,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 57,
          "p95ms24h": 88,
          "samples24h": 272,
          "samples30d": 1100,
          "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": 270,
              "ok": 270
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.sinch.com",
          "indicator": "none",
          "summary": "All Systems Operational",
          "checkedAt": "2026-10-04T23:49:28.041504051Z"
        },
        "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": "2026-10-04T23:49:28.041504051Z"
      }
    },
    "b": {
      "slug": "voximplant",
      "name": "Voximplant",
      "vendor": "Voximplant",
      "vendorUrl": "https://voximplant.com",
      "kind": "http-api",
      "category": "voice-calling",
      "summary": "Serverless platform for programmable calling.",
      "url": "https://www.anchorterminal.com/tools/voximplant",
      "markdownUrl": "https://www.anchorterminal.com/tools/voximplant.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/voximplant.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/voximplant.json",
      "repo": "https://github.com/voximplant/apiclient-nodejs",
      "license": "Apache-2.0",
      "transports": [
        "http"
      ],
      "remoteUrl": "https://api.voximplant.com/platform_api",
      "packages": [
        {
          "registry": "npm",
          "name": "@voximplant/apiclient-nodejs"
        },
        {
          "registry": "pypi",
          "name": "voximplant-apiclient"
        }
      ],
      "auth": "mixed",
      "authNotes": "Management API accepts a service-account JWT (RS256, up to one hour) as a Bearer token, or an account ID and API key in the query string. Prefer the JWT, since query-string keys end up in logs.",
      "pricing": "usage",
      "pricingNotes": "Pay as you go in USD. US outbound $0.017 a minute to landlines and mobiles, inbound $0.005, toll-free inbound $0.03. US numbers $1.50 a month plus $1.50 setup, toll-free $3 a month. WebSocket audio streaming $0.001 per 15 seconds per direction ($0.004 a minute each way). Voice AI connectors $0.001 per 15 seconds ($0.004 a minute), including a bidirectional stream. Recording $0.001 a minute to your own S3 or $0.0015 with 3-month cloud storage. Speech recognition $0.034 a minute (https://voximplant.com/pricing).",
      "priceSummary": "$1.50 / mo",
      "where": "hosted",
      "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": 15,
        "npmWeekly": 1419,
        "pypiWeekly": 930,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://docs.voximplant.ai",
      "llmsTxt": "https://docs.voximplant.ai/llms.txt",
      "openapi": "https://docs.voximplant.ai/openapi.json",
      "capabilities": [
        "voice.calls",
        "voice.numbers",
        "voice.streaming",
        "voice.sip",
        "voice.recording",
        "voice.transfer"
      ],
      "tags": [
        "hosted",
        "llms-txt",
        "openapi",
        "typescript",
        "python",
        "streaming",
        "webhooks"
      ],
      "lastRelease": "2026-08-26",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 51.9,
        "grade": "D",
        "agentReady": false,
        "rank": 346,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 9,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 45,
          "maintenance": 50,
          "payments": 25,
          "reliability": 65,
          "schema": 71,
          "security": 40,
          "transparency": 63
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": 0,
        "verdict": "Call logic runs next to the media, with connectors for the main speech-to-speech models at $0.004 a minute. Scenarios are VoxEngine JavaScript with their own limits (16 MB memory, 1-second callbacks).",
        "strengths": [
          "Call logic runs next to the media, with connectors for the main speech-to-speech models at $0.004 a minute",
          "Service-account JWTs that expire within an hour, with roles per account",
          "OpenAPI spec for the Management API and an llms.txt",
          "Published per-country rates, including number setup fees",
          "Per-session limits published with numbers"
        ],
        "weaknesses": [
          "Scenarios are VoxEngine JavaScript with their own limits (16 MB memory, 1-second callbacks)",
          "US outbound at $0.017 a minute is higher than most here",
          "API key accepted in the query string, and no security.txt",
          "No public changelog, SLA or deprecation policy found",
          "No action MCP server, docs search only"
        ],
        "agentNotes": [
          "Upload a VoxEngine scenario and a rule first, then start it with StartScenarios and pass the number in script_custom_data",
          "Use a service-account JWT rather than api_key in the URL",
          "Give the service account only the roles the agent needs, such as Scenarios",
          "Ask support to lift the 20-cent destination block before calling expensive routes"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 3,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "D",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 51.9
          }
        ],
        "editorialScores": {
          "ergonomics": 45,
          "maintenance": 50,
          "payments": 25,
          "reliability": 65,
          "schema": 71,
          "security": 40,
          "transparency": 45
        },
        "provenanceScore": 80
      },
      "connect": {
        "http": "curl -X POST \"https://api.voximplant.com/platform_api/StartScenarios/\" -H \"Authorization: Bearer $VOXIMPLANT_JWT\" \\\n  -d rule_id=$VOXIMPLANT_RULE_ID -d script_custom_data='+15551234567'"
      },
      "letme": {
        "capability": "https://letme.dev/voice.calls",
        "tool": "https://letme.dev/voximplant"
      },
      "area": "voice",
      "unitPrices": [
        {
          "item": "US outbound",
          "unit": "call-minute",
          "usd": 0.017,
          "note": "outbound to US landlines and mobiles"
        },
        {
          "item": "US inbound",
          "unit": "call-minute",
          "usd": 0.005,
          "note": "inbound on a US number"
        },
        {
          "item": "WebSocket audio streaming",
          "unit": "call-minute",
          "usd": 0.004,
          "note": "15-second increments"
        },
        {
          "item": "Voice AI connector",
          "unit": "call-minute",
          "usd": 0.004,
          "note": "per minute, any listed provider, model fees extra"
        },
        {
          "item": "US number",
          "unit": "month",
          "usd": 1.5,
          "note": "plus $1.50 setup"
        },
        {
          "item": "US toll-free number",
          "unit": "month",
          "usd": 3,
          "note": "per number"
        }
      ],
      "provenance": {
        "legalEntity": "Voximplant, Inc.",
        "domain": "voximplant.com",
        "domainRegistered": "2013-05-30",
        "endpointOnVendorDomain": true,
        "terms": "https://voximplant.com/legal/tos",
        "privacy": "https://voximplant.com/legal/privacy",
        "statusPage": "https://status.voximplant.com",
        "changelog": "",
        "securityTxt": "none",
        "checked": "2026-09-30",
        "notes": [
          "Legal entity from the terms of service. No public changelog found."
        ],
        "score": 80
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/voximplant.json",
      "live": {
        "slug": "voximplant",
        "probe": {
          "target": "https://api.voximplant.com/platform_api",
          "method": "get",
          "lastAt": "2026-10-04T23:48:18.313756979Z",
          "lastOk": true,
          "lastStatus": 200,
          "lastMs": 58,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 60,
          "p95ms24h": 85,
          "samples24h": 272,
          "samples30d": 1100,
          "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": 270,
              "ok": 270
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.voximplant.com",
          "indicator": "none",
          "summary": "All Systems Operational",
          "checkedAt": "2026-10-04T23:49:30.73546758Z"
        },
        "versions": [
          {
            "registry": "npm",
            "name": "@voximplant/apiclient-nodejs",
            "version": "4.11.0",
            "seenAt": "2026-10-04T16:43:49.611417657Z"
          },
          {
            "registry": "pypi",
            "name": "voximplant-apiclient",
            "version": "2.10.0",
            "released": "2026-08-26",
            "seenAt": "2026-10-04T16:43:50.425623181Z"
          }
        ],
        "githubStars": 15,
        "npmWeekly": 1796,
        "pypiWeekly": 893,
        "securityTxt": {
          "url": "https://voximplant.com/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:16:01.143579003Z"
        },
        "llmsTxt": {
          "url": "https://docs.voximplant.ai/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:18:21.661478569Z"
        },
        "domain": {
          "domain": "voximplant.com",
          "registered": "2013-05-30",
          "source": "https://rdap.verisign.com/com/v1/domain/voximplant.com",
          "checkedAt": "2026-10-04T13:06:06.742088675Z"
        },
        "pages": [
          {
            "url": "https://voximplant.com/pricing",
            "kind": "pricing",
            "status": 200,
            "checkedAt": "2026-10-04T15:48:52.131689877Z",
            "changedAt": "2026-10-02T15:25:01.512055599Z",
            "fingerprint": "e337aae5234a"
          },
          {
            "url": "https://voximplant.com/legal/privacy",
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  "markdown": "Sinch Voice API + MCP has a score of 62.8 (B) against Voximplant's 51.9 (D). Both do voice calls. The largest gap is agent ergonomics, 36 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- Voximplant: grade D, 51.9/100, rank #346 of 452. Markdown https://www.anchorterminal.com/tools/voximplant.md · JSON https://www.anchorterminal.com/api/v1/tools/voximplant.json\n\n## Which one, for what\n\nPick Sinch Voice API + MCP for schema \u0026 documentation (+8), agent ergonomics (+36), security \u0026 auth (+10), payments \u0026 pricing (+10), maintenance \u0026 community (+29), transparency \u0026 trust (+10).\n\nPick Voximplant for reliability (+13).\n\n## Score by category\n\n| Category | Weight | Sinch Voice API + MCP | Voximplant | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 52 | 65 | Voximplant +13 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 79 | 71 | Sinch Voice API + MCP +8 |\n| Agent ergonomics | 13% (16.2 this run) | 81 | 45 | Sinch Voice API + MCP +36 |\n| Security \u0026 auth | 14% (17.5 this run) | 50 | 40 | Sinch Voice API + MCP +10 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 35 | 25 | Sinch Voice API + MCP +10 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 79 | 50 | Sinch Voice API + MCP +29 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 73 | 63 | Sinch Voice API + MCP +10 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **62.8 · B** | **51.9 · D** | |\n\n## Facts side by side\n\n| Fact | Sinch Voice API + MCP | Voximplant |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Sinch | Voximplant |\n| Hosted endpoint | `https://voice.api.sinch.com/v2` | `https://api.voximplant.com/platform_api` |\n| Transports | HTTP, stdio, Streamable HTTP | 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 | Apache-2.0 |\n| Tools exposed | none | none |\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 | 2026-09-23 | 2026-08-26 |\n| Popularity | 1 stars, 16k npm/wk, 11k PyPI/wk | 15 stars, 1.4k npm/wk, 930 PyPI/wk |\n| Agent reviews | 3/5 (2) | 3/5 (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**Voximplant.** Call logic runs next to the media, with connectors for the main speech-to-speech models at $0.004 a minute. Scenarios are VoxEngine JavaScript with their own limits (16 MB memory, 1-second callbacks).\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### Voximplant\n\n1. Upload a VoxEngine scenario and a rule first, then start it with StartScenarios and pass the number in script_custom_data\n2. Use a service-account JWT rather than api_key in the URL\n3. Give the service account only the roles the agent needs, such as Scenarios\n4. Ask support to lift the 20-cent destination block before calling expensive routes\n\n## Other comparisons with Sinch Voice API + MCP or Voximplant\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 Voximplant](https://www.anchorterminal.com/compare/bandwidth-voice-vs-voximplant.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 Voximplant](https://www.anchorterminal.com/compare/exotel-voice-vs-voximplant.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 Voximplant](https://www.anchorterminal.com/compare/infobip-calls-vs-voximplant.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 Voximplant](https://www.anchorterminal.com/compare/plivo-voice-vs-voximplant.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 Voximplant](https://www.anchorterminal.com/compare/signalwire-voice-vs-voximplant.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 Vonage Voice API + MCP](https://www.anchorterminal.com/compare/sinch-voice-vs-vonage-voice.md)\n- [Telnyx Voice API + MCP vs Voximplant](https://www.anchorterminal.com/compare/telnyx-voice-vs-voximplant.md)\n- [Twilio Programmable Voice API + MCP vs Voximplant](https://www.anchorterminal.com/compare/twilio-voice-vs-voximplant.md)\n- [Vonage Voice API + MCP vs Voximplant](https://www.anchorterminal.com/compare/vonage-voice-vs-voximplant.md)\n",
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    "description": "Sinch Voice API + MCP has a score of 62.8 (B) against Voximplant's 51.9 (D). Both do voice calls. The largest gap is agent ergonomics, 36 points. Category scores, facts, verdicts and agent notes side by side.",
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    "title": "Sinch Voice API + MCP vs Voximplant for AI agents, B 62.8 vs D 51.9",
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