{ "data": { "a": { "slug": "cartesia-tts", "name": "Cartesia Sonic TTS API + MCP", "vendor": "Cartesia", "vendorUrl": "https://cartesia.ai", "kind": "model", "category": "text-to-speech", "summary": "Sonic text-to-speech, currently `sonic-3.6` in 44 languages, over `/tts/bytes`, `/tts/sse` and a WebSocket that takes streamed LLM text with contexts and word timestamps.", "url": "https://www.anchorterminal.com/tools/cartesia-tts", "markdownUrl": "https://www.anchorterminal.com/tools/cartesia-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/cartesia-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json", "repo": "https://github.com/cartesia-ai/cartesia-python", "license": "Apache-2.0 (SDKs)", "transports": [ "http", "streamable-http", "stdio" ], "remoteUrl": "https://api.cartesia.ai", "packages": [ { "registry": "npm", "name": "@cartesia/cartesia-js" }, { "registry": "pypi", "name": "cartesia" }, { "registry": "pypi", "name": "cartesia-mcp" } ], "auth": "mixed", "authNotes": "`Authorization: Bearer` API key plus a required `Cartesia-Version` date header (currently `2026-08-14`). Browsers should use short-lived access tokens minted server-side. The hosted MCP at `https://mcp.cartesia.ai/mcp` signs in through the Playground and creates an MCP key. The local `cartesia-mcp` reads `CARTESIA_API_KEY`.", "pricing": "freemium", "pricingNotes": "TTS costs about 1 credit a character, charged only on successful requests. Free has 20,000 credits a month (about 27 minutes of Sonic 3.6), Pro $5 100,000, Startup $49 1.25M and Scale $299 8M. Overages, if enabled, cost $65 per 1M credits on Pro, $45 on Startup and $38 on Scale. Commercial use starts at Pro. Unused credits roll over up to 2 times the monthly amount (https://cartesia.ai/pricing).", "priceSummary": "$5 / mo", "where": "both", "x402": { "level": "no", "evidence": "No x402 or machine payment in the docs or pricing (checked 2026-09-30).", "endpoints": [] }, "toolCount": 15, "popularity": { "githubStars": 133, "npmWeekly": 166023, "pypiWeekly": 176771, "asOf": "2026-09-30" }, "docsUrl": "https://docs.cartesia.ai/build-with-cartesia/tts-models/latest", "llmsTxt": "https://docs.cartesia.ai/llms.txt", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.ssml", "speech.languages" ], "tags": [ "hosted", "freemium", "free-tier", "closed-source", "python", "typescript", "llms-txt", "mcp", "streaming", "enterprise" ], "lastRelease": "2026-09-30", "graded": true, "anchor": { "graded": true, "score": 64.2, "grade": "B", "agentReady": false, "rank": 187, "ranked": true, "rankOf": 452, "categoryRank": 6, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 65, "maintenance": 79, "payments": 30, "reliability": 63, "schema": 86, "security": 58, "transparency": 71 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "WebSocket input accepts streamed LLM text with contexts, flushing and word timestamps. Five TTS incidents on the status page between 29 July and 21 August 2026.", "strengths": [ "WebSocket input accepts streamed LLM text with contexts, flushing and word timestamps", "Dated model snapshots such as `sonic-3.6-2026-08-27` never change, and `Cartesia-Version` pins the API shape", "OpenAPI and AsyncAPI files per API version listed in llms.txt", "Short-lived access tokens with TTS, STT and agent grants for browser clients", "Deprecations dated in the changelog, Sonic-2 and Sonic Turbo sunset after 2026-10-20" ], "weaknesses": [ "Five TTS incidents on the status page between 29 July and 21 August 2026", "TTS concurrency is 2 on Free, 3 on Pro, 5 on Startup and 15 on Scale", "The Terms allow training on inputs and outputs unless you opt out by form", "Zero data retention is Enterprise only", "No SLA, and no error responses documented for the TTS endpoints" ], "agentNotes": [ "Send the `Cartesia-Version` header on every request.", "Pin a dated snapshot such as `sonic-3.6-2026-08-27` if output must not change.", "Move off `sonic-2`, `sonic-turbo` and `sonic-3-2025-10-27` before 2026-10-20.", "Expect a 429 at the plan's concurrency limit and queue requests yourself.", "Mint a short-lived access token for browser clients instead of shipping the API key." ], "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": 64.2 } ], "editorialScores": { "ergonomics": 65, "maintenance": 79, "payments": 30, "reliability": 63, "schema": 86, "security": 58, "transparency": 60 }, "provenanceScore": 82 }, "connect": { "http": "curl -X POST https://api.cartesia.ai/tts/bytes -H \"Authorization: Bearer $CARTESIA_API_KEY\" \\\n -H \"Cartesia-Version: 2026-08-14\" -H \"content-type: application/json\" -o speech.wav \\\n -d '{\"model_id\":\"sonic-3.6\",\"transcript\":\"Your table is booked for seven.\",\"voice\":{\"id\":\"47c38ca4-5f35-497b-b1a3-415245fb35e1\"},\"output_format\":{\"container\":\"wav\",\"encoding\":\"pcm_s16le\",\"sample_rate\":44100}}'", "claudeCode": "claude mcp add --transport http --scope user cartesia https://mcp.cartesia.ai/mcp", "config": { "mcpServers": { "cartesia": { "args": [ "cartesia-mcp" ], "command": "uvx", "env": { "CARTESIA_API_KEY": "${CARTESIA_API_KEY}" } } } } }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/cartesia-tts" }, "sameCompany": [ "cartesia-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Sonic TTS overage on Pro", "unit": "1m-chars", "usd": 65, "note": "about 1 credit a character, $65 per 1M credits" }, { "item": "Sonic TTS overage on Startup", "unit": "1m-chars", "usd": 45 }, { "item": "Sonic TTS overage on Scale", "unit": "1m-chars", "usd": 38 }, { "item": "Pro plan", "unit": "month", "usd": 5, "note": "100,000 credits" }, { "item": "Startup plan", "unit": "month", "usd": 49, "note": "1.25M credits" }, { "item": "Scale plan", "unit": "month", "usd": 299, "note": "8M credits" } ], "provenance": { "legalEntity": "Cartesia AI, Inc.", "domain": "cartesia.ai", "domainRegistered": "2023-05-10", "endpointOnVendorDomain": true, "terms": "https://www.cartesia.ai/legal/terms", "privacy": "https://www.cartesia.ai/legal/privacy", "statusPage": "https://status.cartesia.ai", "changelog": "https://docs.cartesia.ai/changelog/2026", "securityTxt": "none", "checked": "2026-09-30", "score": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/cartesia-tts.json", "live": { "slug": "cartesia-tts", "probe": { "target": "https://api.cartesia.ai", "method": "get", "lastAt": "2026-10-05T00:25:40.801190313Z", "lastOk": true, "lastStatus": 200, "lastMs": 92, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 61, "p95ms24h": 137, "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.cartesia.ai", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-05T00:22:38.61205555Z" }, "versions": [ { "registry": "github", "name": "cartesia-ai/cartesia-python", "version": "v4.2.0", "released": "2026-09-02", "seenAt": "2026-10-04T16:23:11.882857509Z" }, { "registry": "npm", "name": "@cartesia/cartesia-js", "version": "4.2.0", "seenAt": "2026-10-04T16:23:08.936594762Z" }, { "registry": "pypi", "name": "cartesia", "version": "4.2.0", "released": "2026-09-02", "seenAt": "2026-10-04T16:23:09.798087978Z" }, { "registry": "pypi", "name": "cartesia-mcp", "version": "0.26.0", "released": "2026-09-30", "seenAt": "2026-10-04T16:23:09.984461576Z" } ], "githubStars": 133, "npmWeekly": 108942, "pypiWeekly": 188249, "securityTxt": { "url": "https://cartesia.ai/.well-known/security.txt", "state": "valid", "expires": "2027-10-03T00:00:00.000Z", "checkedAt": "2026-10-04T15:15:57.920556028Z" }, "llmsTxt": { "url": "https://docs.cartesia.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:17:23.748277625Z" }, "domain": { "domain": "cartesia.ai", "registered": "2023-05-10", "source": "https://rdap.identitydigital.services/rdap/domain/cartesia.ai", "checkedAt": "2026-10-04T13:04:05.26596839Z" }, "pages": [ { "url": "https://docs.cartesia.ai/changelog/2026", "kind": "changelog", "status": 200, "checkedAt": "2026-10-04T15:43:22.154553148Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "56a07dda1f5d" }, { "url": "https://cartesia.ai/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-04T15:41:44.64571005Z", "changedAt": "2026-10-03T15:29:56.901063562Z", "fingerprint": "3e49bcd49fcf" }, { "url": "https://www.cartesia.ai/legal/privacy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-04T15:49:41.751185158Z", "changedAt": "2026-10-03T15:37:37.717663201Z", "fingerprint": "6fea00c7255f" }, { "url": "https://www.cartesia.ai/legal/terms", "kind": "terms", "status": 200, "checkedAt": "2026-10-04T15:49:43.846741137Z", "changedAt": "2026-10-03T15:37:39.779484537Z", "fingerprint": "c899e30661ba" } ], "updatedAt": "2026-10-05T00:25:40.801190313Z" } }, "b": { "slug": "elevenlabs-tts", "name": "ElevenLabs Text to Speech API + MCP", "vendor": "ElevenLabs", "vendorUrl": "https://elevenlabs.io", "kind": "model", "category": "text-to-speech", "summary": "ElevenLabs text-to-speech over REST, HTTP streaming and WebSocket.", "url": "https://www.anchorterminal.com/tools/elevenlabs-tts", "markdownUrl": "https://www.anchorterminal.com/tools/elevenlabs-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/elevenlabs-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/elevenlabs-tts.json", "repo": "https://github.com/elevenlabs/elevenlabs-python", "license": "MIT (SDKs)", "transports": [ "http", "streamable-http", "stdio" ], "remoteUrl": "https://api.elevenlabs.io/v1", "packages": [ { "registry": "npm", "name": "@elevenlabs/elevenlabs-js" }, { "registry": "pypi", "name": "elevenlabs" }, { "registry": "pypi", "name": "elevenlabs-mcp" } ], "auth": "mixed", "authNotes": "`xi-api-key` header for the REST and WebSocket APIs. The hosted MCP at `https://api.elevenlabs.io/v1/mcp` signs in with OAuth, scoped to Agents and Text to Speech. The older local `elevenlabs-mcp` server reads `ELEVENLABS_API_KEY` and is now deprecated. Data residency hosts exist for the EU, India and Singapore.", "pricing": "freemium", "pricingNotes": "API usage is priced per 1,000 characters. Eleven v4, v3 and Multilingual v2 cost $0.08, v4 Turbo, v3 Conversational and Flash/Turbo $0.04. Eleven v4 is at $0.022 and v4 Turbo at $0.011 until 2026-10-12. Plans are Free (10,000 v4 characters), Starter $6, Creator $22 ($11 first month), Pro $99, Scale $299 and Business $990 a month, with pay-as-you-go as an alternative. Commercial use starts at Starter (https://elevenlabs.io/pricing/api).", "priceSummary": "$6 / mo", "where": "both", "x402": { "level": "no", "evidence": "No x402 or machine payment in the docs or pricing. Subscription or pay-as-you-go card billing (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 3122, "npmWeekly": 1063065, "pypiWeekly": 2223099, "asOf": "2026-09-30" }, "docsUrl": "https://elevenlabs.io/docs/overview/capabilities/text-to-speech", "llmsTxt": "https://elevenlabs.io/docs/llms.txt", "openapi": "https://api.elevenlabs.io/openapi.json", "registryName": "io.elevenlabs/mcp", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.ssml", "speech.languages" ], "tags": [ "hosted", "freemium", "free-tier", "closed-source", "python", "typescript", "openapi", "llms-txt", "mcp", "streaming", "enterprise" ], "lastRelease": "2026-09-28", "graded": true, "anchor": { "graded": true, "score": 73.1, "grade": "BB", "agentReady": true, "rank": 61, "ranked": true, "rankOf": 452, "categoryRank": 3, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 82, "maintenance": 77, "payments": 40, "reliability": 80, "schema": 94, "security": 60, "transparency": 71 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "high", "date": "2026-10-01" }, "negative": 0, "verdict": "Keys can be limited to chosen endpoints and given a credit quota, and service accounts hold keys that don't belong to a person. Content may be used for training unless you opt out under Data use, and the opt-out only applies going forward.", "strengths": [ "Keys can be limited to chosen endpoints and given a credit quota, and service accounts hold keys that don't belong to a person", "Error reference with about 90 codes, each carrying `type`, `code`, `message` and `request_id`", "OpenAPI file, llms.txt and Markdown twins of every docs page", "Free plan with 10,000 v4 characters a month and no card", "Weekly dated changelog, 16 entries between 6 July and 28 September 2026" ], "weaknesses": [ "Content may be used for training unless you opt out under Data use, and the opt-out only applies going forward", "Zero retention (`enable_logging=false`) is Enterprise only, and TTS text and audio are kept by default", "No SLA published for self-serve plans", "Eleven v4 and v3 ignore SSML `\u003cbreak\u003e` tags", "v4 rises from $0.022 to $0.08 per 1,000 characters after 2026-10-12" ], "agentNotes": [ "Call Eleven v4 through Text to Dialogue, not `/v1/text-to-speech`.", "Spell out numbers yourself on `eleven_flash_v2_5`, which doesn't normalise them by default, and turning that on is Enterprise only.", "On 429 read `code`, back off on `rate_limit_exceeded` and wait for running requests on `concurrent_limit_exceeded`.", "Keep each request under 10,000 characters on v4 and Multilingual v2, 5,000 on v3.", "Give the agent a key scoped to Text to Speech with a credit quota." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3.5, "history": [ { "basis": "public evidence", "confidence": "high", "grade": "BB", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 73.1 } ], "editorialScores": { "ergonomics": 82, "maintenance": 77, "payments": 40, "reliability": 80, "schema": 94, "security": 60, "transparency": 50 }, "provenanceScore": 92 }, "connect": { "http": "curl -X POST \"https://api.elevenlabs.io/v1/text-to-speech/JBFqnCBsd6RMkjVDRZzb?output_format=mp3_44100_128\" \\\n -H \"xi-api-key: $ELEVENLABS_API_KEY\" -H \"content-type: application/json\" -o speech.mp3 \\\n -d '{\"text\":\"Your table is booked for seven.\",\"model_id\":\"eleven_flash_v2_5\"}'", "claudeCode": "claude mcp add --transport http elevenlabs https://api.elevenlabs.io/v1/mcp", "config": { "mcpServers": { "elevenlabs": { "args": [ "elevenlabs-mcp" ], "command": "uvx", "env": { "ELEVENLABS_API_KEY": "${ELEVENLABS_API_KEY}" } } } } }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/elevenlabs-tts" }, "sameCompany": [ "elevenlabs-music", "elevenlabs-scribe", "elevenlabs-agents", "elevenlabs-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Eleven v4", "unit": "1m-chars", "usd": 80, "note": "$22 until 2026-10-12" }, { "item": "Eleven v4 Turbo", "unit": "1m-chars", "usd": 40, "note": "$11 until 2026-10-12" }, { "item": "Eleven v3 / Multilingual v2", "unit": "1m-chars", "usd": 80 }, { "item": "Flash v2.5 / v3 Conversational", "unit": "1m-chars", "usd": 40 }, { "item": "Starter plan", "unit": "month", "usd": 6, "note": "about 273,000 v4 characters" }, { "item": "Creator plan", "unit": "month", "usd": 22, "note": "about 1M v4 characters" } ], "provenance": { "legalEntity": "Eleven Labs Inc.", "domain": "elevenlabs.io", "domainRegistered": "2021-12-15", "endpointOnVendorDomain": true, "terms": "https://elevenlabs.io/terms-of-use", "privacy": "https://elevenlabs.io/privacy-policy", "statusPage": "https://status.elevenlabs.io", "changelog": "https://elevenlabs.io/docs/changelog", "securityTxt": "valid", "checked": "2026-09-30", "score": 92 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/elevenlabs-tts.json", "live": { "slug": "elevenlabs-tts", "probe": { "target": "https://api.elevenlabs.io/v1", "method": "get", "lastAt": "2026-10-05T00:25:42.518269032Z", "lastOk": true, "lastStatus": 404, "lastMs": 119, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 118, "p95ms24h": 152, "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.elevenlabs.io", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-05T00:22:43.719122539Z" }, "versions": [ { "registry": "github", "name": "elevenlabs/elevenlabs-python", "version": "v2.70.0", "released": "2026-09-28", "seenAt": "2026-10-04T16:26:21.788463226Z" }, { "registry": "mcp-registry", "name": "io.elevenlabs/mcp", "version": "1.0.0", "seenAt": "2026-10-04T23:42:40.113054682Z" }, { "registry": "npm", "name": "@elevenlabs/elevenlabs-js", "version": "2.70.0", "seenAt": "2026-10-04T16:26:19.471925531Z" }, { "registry": "pypi", "name": "elevenlabs", "version": "2.70.0", "released": "2026-09-28", "seenAt": "2026-10-04T16:26:19.782214789Z" }, { "registry": "pypi", "name": "elevenlabs-mcp", "version": "0.12.2", "released": "2026-08-04", "seenAt": "2026-10-04T16:26:19.89529303Z" } ], "githubStars": 3129, "npmWeekly": 1135260, "pypiWeekly": 2247596, "securityTxt": { "url": "https://elevenlabs.io/.well-known/security.txt", "state": "valid", "expires": "2027-03-01T00:00:00.000Z", "checkedAt": "2026-10-04T15:15:51.968224287Z" }, "llmsTxt": { "url": "https://elevenlabs.io/docs/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:17:54.328986649Z" }, "domain": { "domain": "elevenlabs.io", "checkedAt": "2026-10-04T13:07:28.958673807Z" }, "updatedAt": "2026-10-05T00:25:42.518269032Z" } }, "summary": "ElevenLabs Text to Speech API + MCP has a score of 73.1 (BB) against Cartesia Sonic TTS API + MCP's 64.2 (B). Both do speech tts. The largest gap is reliability, 17 points." }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-tts", "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-tts.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-tts.md", "slim": "https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-tts.min.md" }, "markdown": "ElevenLabs Text to Speech API + MCP has a score of 73.1 (BB) against Cartesia Sonic TTS API + MCP's 64.2 (B). Both do speech tts. The largest gap is reliability, 17 points.\n\n- Cartesia Sonic TTS API + MCP: grade B, 64.2/100, rank #187 of 452. Markdown https://www.anchorterminal.com/tools/cartesia-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json\n- ElevenLabs Text to Speech API + MCP: grade BB, 73.1/100, rank #61 of 452. Markdown https://www.anchorterminal.com/tools/elevenlabs-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/elevenlabs-tts.json\n\n## Which one, for what\n\nPick Cartesia Sonic TTS API + MCP for nothing in particular (no category where it leads by five points or more).\n\nPick ElevenLabs Text to Speech API + MCP for reliability (+17), schema \u0026 documentation (+8), agent ergonomics (+17), payments \u0026 pricing (+10).\n\n## Score by category\n\n| Category | Weight | Cartesia Sonic TTS API + MCP | ElevenLabs Text to Speech API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 63 | 80 | ElevenLabs Text to Speech API + MCP +17 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 86 | 94 | ElevenLabs Text to Speech API + MCP +8 |\n| Agent ergonomics | 13% (16.2 this run) | 65 | 82 | ElevenLabs Text to Speech API + MCP +17 |\n| Security \u0026 auth | 14% (17.5 this run) | 58 | 60 | ElevenLabs Text to Speech API + MCP +2 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 30 | 40 | ElevenLabs Text to Speech 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 | 77 | Cartesia Sonic TTS API + MCP +2 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 71 | 71 | even |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **64.2 · B** | **73.1 · BB** | |\n\n## Facts side by side\n\n| Fact | Cartesia Sonic TTS API + MCP | ElevenLabs Text to Speech API + MCP |\n| --- | --- | --- |\n| Kind | Model API | Model API |\n| Vendor | Cartesia | ElevenLabs |\n| Hosted endpoint | `https://api.cartesia.ai` | `https://api.elevenlabs.io/v1` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP, stdio |\n| Auth | OAuth or key | OAuth or key |\n| Pricing | Freemium | Freemium |\n| x402 | no | no |\n| Licence | Apache-2.0 (SDKs) | MIT (SDKs) |\n| Tools exposed | 15 | 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 | `io.elevenlabs/mcp` |\n| Last release | 2026-09-30 | 2026-09-28 |\n| Popularity | 133 stars, 166k npm/wk, 177k PyPI/wk | 3.1k stars, 1.1M npm/wk, 2.2M PyPI/wk |\n| Agent reviews | 3/5 (2) | 3.5/5 (2) |\n\n## Verdicts\n\n**Cartesia Sonic TTS API + MCP.** WebSocket input accepts streamed LLM text with contexts, flushing and word timestamps. Five TTS incidents on the status page between 29 July and 21 August 2026.\n\n**ElevenLabs Text to Speech API + MCP.** Keys can be limited to chosen endpoints and given a credit quota, and service accounts hold keys that don't belong to a person. Content may be used for training unless you opt out under Data use, and the opt-out only applies going forward.\n\n## Before you call either\n\n### Cartesia Sonic TTS API + MCP\n\n1. Send the `Cartesia-Version` header on every request.\n2. Pin a dated snapshot such as `sonic-3.6-2026-08-27` if output must not change.\n3. Move off `sonic-2`, `sonic-turbo` and `sonic-3-2025-10-27` before 2026-10-20.\n4. Expect a 429 at the plan's concurrency limit and queue requests yourself.\n5. Mint a short-lived access token for browser clients instead of shipping the API key.\n\n### ElevenLabs Text to Speech API + MCP\n\n1. Call Eleven v4 through Text to Dialogue, not `/v1/text-to-speech`.\n2. Spell out numbers yourself on `eleven_flash_v2_5`, which doesn't normalise them by default, and turning that on is Enterprise only.\n3. On 429 read `code`, back off on `rate_limit_exceeded` and wait for running requests on `concurrent_limit_exceeded`.\n4. Keep each request under 10,000 characters on v4 and Multilingual v2, 5,000 on v3.\n5. Give the agent a key scoped to Text to Speech with a credit quota.\n\n## Other comparisons with Cartesia Sonic TTS API + MCP or ElevenLabs Text to Speech API + MCP\n\n- [Amazon Polly vs Cartesia Sonic TTS API + MCP](https://www.anchorterminal.com/compare/amazon-polly-vs-cartesia-tts.md)\n- [Amazon Polly vs ElevenLabs Text to Speech API + MCP](https://www.anchorterminal.com/compare/amazon-polly-vs-elevenlabs-tts.md)\n- [Azure AI Speech text-to-speech vs Cartesia Sonic TTS API + MCP](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-cartesia-tts.md)\n- [Azure AI Speech text-to-speech vs ElevenLabs Text to Speech API + MCP](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-elevenlabs-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Deepgram Text-to-Speech (Aura-2, Flux TTS)](https://www.anchorterminal.com/compare/cartesia-tts-vs-deepgram-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/cartesia-tts-vs-murf-tts.md)\n- [Cartesia Sonic TTS API + MCP vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/cartesia-tts-vs-playht-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/cartesia-tts-vs-rime-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/cartesia-tts-vs-soniox-tts.md)\n- [Deepgram Text-to-Speech (Aura-2, Flux TTS) vs ElevenLabs Text to Speech API + MCP](https://www.anchorterminal.com/compare/deepgram-tts-vs-elevenlabs-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-murf-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-playht-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-resemble-ai-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-rime-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-soniox-tts.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": "Cartesia Sonic TTS API + MCP vs ElevenLabs Text to Speech API + MCP", "url": "" } ], "description": "ElevenLabs Text to Speech API + MCP has a score of 73.1 (BB) against Cartesia Sonic TTS API + MCP's 64.2 (B). Both do speech tts. The largest gap is reliability, 17 points. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Cartesia Sonic TTS API + MCP B 64.2", "ElevenLabs Text to Speech API + MCP BB 73.1", "scores" ], "h1": "Cartesia Sonic TTS API + MCP vs ElevenLabs Text to Speech API + MCP", "image": "https://www.anchorterminal.com/assets/og/compare-cartesia-tts-vs-elevenlabs-tts.png", "path": "/compare/cartesia-tts-vs-elevenlabs-tts", "published": "2026-10-01", "section": "tools", "title": "Cartesia Sonic TTS API + MCP vs ElevenLabs Text to Speech API + MCP", "toc": null, "updated": "2026-10-05", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-tts" }, "tokens": { "markdown": 1850, "slim": 380 }, "version": 1 }