{ "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": 63.8, "grade": "B", "agentReady": false, "rank": 335, "ranked": true, "rankOf": 842, "categoryRank": 6, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 65, "maintenance": 79, "payments": 30, "reliability": 63, "schema": 86, "security": 58, "transparency": 67 }, "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.", "bestFor": "Real-time voice agents that stream LLM output straight into speech and need stable, pinnable models.", "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": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 63.8 } ], "editorialScores": { "ergonomics": 65, "maintenance": 79, "payments": 30, "reliability": 63, "schema": 86, "security": 58, "transparency": 60 }, "provenanceScore": 74 }, "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": 74 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/cartesia-tts.json", "live": { "slug": "cartesia-tts", "probe": { "target": "https://api.cartesia.ai", "method": "get", "lastAt": "2026-10-09T11:46:25.001858323Z", "lastOk": true, "lastStatus": 200, "lastMs": 57, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 65, "p95ms24h": 131, "samples24h": 259, "samples30d": 2311, "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": 272, "ok": 272 }, { "date": "2026-10-06", "probes": 272, "ok": 272 }, { "date": "2026-10-07", "probes": 272, "ok": 272 }, { "date": "2026-10-08", "probes": 268, "ok": 268 }, { "date": "2026-10-09", "probes": 125, "ok": 125 } ] }, "vendorStatus": { "page": "https://status.cartesia.ai", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-09T11:38:24.575231825Z" }, "versions": [ { "registry": "github", "name": "cartesia-ai/cartesia-python", "version": "v4.2.0", "released": "2026-09-02", "seenAt": "2026-10-08T16:04:35.630169669Z" }, { "registry": "npm", "name": "@cartesia/cartesia-js", "version": "4.2.0", "seenAt": "2026-10-08T16:04:29.519679644Z" }, { "registry": "pypi", "name": "cartesia", "version": "4.2.0", "released": "2026-09-02", "seenAt": "2026-10-08T16:04:33.10890709Z" }, { "registry": "pypi", "name": "cartesia-mcp", "version": "0.26.0", "released": "2026-09-30", "seenAt": "2026-10-08T16:04:33.302806Z" } ], "githubStars": 134, "npmWeekly": 103248, "pypiWeekly": 200265, "securityTxt": { "url": "https://cartesia.ai/.well-known/security.txt", "state": "valid", "expires": "2027-10-03T00:00:00.000Z", "checkedAt": "2026-10-08T15:39:07.996817567Z" }, "llmsTxt": { "url": "https://docs.cartesia.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-08T14:00:11.113541196Z" }, "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": "2026-10-08T18:18:24.003636335Z", "changedAt": "2026-10-07T18:04:49.25388057Z", "fingerprint": "405fadad924b" }, { "url": "https://cartesia.ai/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-08T18:16:00.56995349Z", "changedAt": "2026-10-06T16:06:13.196074501Z", "fingerprint": "522d1763181c" }, { "url": "https://www.cartesia.ai/legal/privacy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-08T18:26:54.204830291Z", "changedAt": "2026-10-08T18:26:54.204830291Z", "fingerprint": "2750d7de8d7c" }, { "url": "https://www.cartesia.ai/legal/terms", "kind": "terms", "status": 200, "checkedAt": "2026-10-08T18:26:56.591248396Z", "changedAt": "2026-10-08T18:26:56.591248396Z", "fingerprint": "a146b5cf872a" } ], "updatedAt": "2026-10-09T11:46:25.001858323Z" } }, "answer": "Cartesia Sonic TTS API + MCP scores 63.8 (B) on agent readiness against Fish Audio TTS API's 60.7 (C), and leads in 4 of 7 scored categories. Fish Audio TTS API leads on reliability.", "b": { "slug": "fish-audio-tts", "name": "Fish Audio TTS API", "vendor": "Fish Audio", "vendorUrl": "https://fish.audio", "kind": "model", "category": "text-to-speech", "summary": "Fish Audio's API turns text into speech with the `s2.1-pro` model in 83 languages, over a REST endpoint, a timestamped stream and a WebSocket that accepts text as it is produced.", "url": "https://www.anchorterminal.com/tools/fish-audio-tts", "markdownUrl": "https://www.anchorterminal.com/tools/fish-audio-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/fish-audio-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/fish-audio-tts.json", "repo": "https://github.com/fishaudio/fish-audio-python", "license": "Apache-2.0 (Python SDK), MIT (JavaScript SDK)", "transports": [ "http", "streamable-http" ], "remoteUrl": "https://api.fish.audio", "packages": [ { "registry": "pypi", "name": "fish-audio-sdk" }, { "registry": "npm", "name": "fish-audio" } ], "auth": "mixed", "authNotes": "`Authorization: Bearer` API key created in the web app after a browser signup with email verification. A key takes a name and an optional expiry. The `model` request header selects the model. The hosted MCP server at `https://api.fish.audio/mcp` signs in by OAuth and is bound to one team (https://docs.fish.audio/developer-guide/getting-started/api-key, https://docs.fish.audio/overview/mcp).", "pricing": "usage", "pricingNotes": "$15 per million UTF-8 bytes of input text on `s2.1-pro`, `s2-pro` and `s1`, prepaid with no subscription or monthly minimum. `s2.1-pro-free` costs $0 under fair-use limits, and the changelog says it is free through 30 November 2026. An agent can start on the free model once a person has signed up. Whether a card is needed is not stated. Concurrency rises with total prepaid amount. MCP usage draws on web app plan credits, not API credits (https://docs.fish.audio/developer-guide/models-pricing/pricing-and-rate-limits).", "priceSummary": "Pay per use", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the developer docs, the OpenAPI file or the pricing page (checked 2026-10-09).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": null, "npmWeekly": 5213, "pypiWeekly": 34220, "asOf": "2026-10-09" }, "docsUrl": "https://docs.fish.audio/features/text-to-speech", "llmsTxt": "https://docs.fish.audio/llms.txt", "openapi": "https://docs.fish.audio/api-reference/openapi.json", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.languages", "voice.clone" ], "tags": [ "hosted", "usage-priced", "prepaid", "free-tier", "closed-source", "python", "typescript", "openapi", "llms-txt", "mcp", "streaming", "status-page", "open-weights" ], "lastRelease": "2026-09-23", "graded": true, "anchor": { "graded": true, "score": 60.7, "grade": "C", "agentReady": false, "rank": 453, "ranked": true, "rankOf": 842, "categoryRank": 8, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 67, "maintenance": 69, "payments": 30, "reliability": 75, "schema": 84, "security": 35, "transparency": 60 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-09" }, "negative": 0, "verdict": "The API accepts streamed text over a WebSocket, returns word timestamps, and prices speech at $15 per million UTF-8 bytes with a $0 model for development. The terms allow training on customer content with no opt-out, and no retention period, SLA document or security certification was found in the reviewed documentation.", "bestFor": "Voice agents that stream LLM text into speech at a low per-byte price, multilingual output from one model, and teams moving from OpenAI or ElevenLabs request shapes.", "strengths": [ "Public OpenAPI 3.1 file, llms.txt, Markdown pages and two installable agent skills for the SDKs and the raw API", "WebSocket input takes text as it is produced, with `flush` and `stop` events and a variant that returns word timestamps", "`s2.1-pro-free` runs the production model at $0 under fair-use limits, through 30 November 2026", "OpenAI-compatible and ElevenLabs-compatible endpoints refuse unsupported options with a 4xx and send `Retry-After` on a 429", "S1 retirement was announced on 8 October 2026 for 31 December 2026, with a migration guide" ], "weaknesses": [ "The terms allow Usage Data and Content to train models, with no opt-out found", "An unrecognised `model` header falls back to paid `s2.1-pro` without an error", "The Text-to-Speech API status component shows downtime on 11 days in 90, the longest 58 minutes on 6 August 2026, mostly on the free model", "The published SDKs date from March 2026. `fish-audio` 0.1.0 on npm defaults to the deprecated `s1`", "No security.txt, certification, DPA text or sub-processor list found in the pages read" ], "agentNotes": [ "Send the `model` header on every request and check its spelling. A missing or unknown value is served and billed as `s2.1-pro`.", "Budget by UTF-8 bytes, not characters. Chinese, Japanese and Korean text costs about three bytes a character.", "Retry 429 and 5xx with exponential backoff. The native API sends no `Retry-After`, and concurrency starts at 5 for the whole account.", "Use `[bracket]` cues on the S2 family. `(parenthesis)` tags from `s1` are read aloud as text.", "Pass the model explicitly in the JavaScript SDK, because npm release 0.1.0 defaults to `s1`." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 60.7 } ], "editorialScores": { "ergonomics": 67, "maintenance": 69, "payments": 30, "reliability": 75, "schema": 84, "security": 35, "transparency": 44 }, "provenanceScore": 75 }, "connect": { "install": "pip install fish-audio-sdk", "http": "curl --request POST https://api.fish.audio/v1/tts \\\n --header \"Authorization: Bearer $FISH_API_KEY\" \\\n --header \"Content-Type: application/json\" \\\n --header \"model: s2.1-pro-free\" \\\n --data '{ \"text\": \"Hello from Fish Audio!\", \"format\": \"mp3\" }' \\\n --output hello.mp3", "claudeCode": "claude mcp add --transport http fish-audio https://api.fish.audio/mcp", "config": { "mcpServers": { "fish-audio": { "url": "https://api.fish.audio/mcp" } } } }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/fish-audio-tts" }, "sameCompany": [ "fish-audio-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Text to speech, s2.1-pro", "unit": "1m-chars", "usd": 15, "note": "per million UTF-8 bytes of input text, not characters" }, { "item": "Text to speech, s2.1-pro-free", "unit": "1m-chars", "usd": 0, "note": "fair-use limits, free through 30 November 2026 per the changelog" } ], "provenance": { "legalEntity": "Hanabi AI Inc.", "domain": "fish.audio", "domainRegistered": "2023-12-11", "endpointOnVendorDomain": true, "terms": "https://fish.audio/terms/", "privacy": "https://fish.audio/privacy/", "statusPage": "https://status.fish.audio", "changelog": "https://docs.fish.audio/developer-guide/getting-started/changelog", "securityTxt": "none", "checked": "2026-10-09", "notes": [ "The Terms of Use (effective 18 August 2024) name Hanabi AI Inc., a Delaware corporation at 1111B S Governors Ave STE 48109, Dover, DE 19904, as the provider of the Services, and cover API keys.", "The Privacy Policy is dated 28 August 2024.", "https://fish.audio/.well-known/security.txt returned 404 on 2026-10-09.", "RDAP for fish.audio gives a registration date of 2023-12-11.", "The terms forbid crawling or scraping any page of the Services by manual or automated means. robots.txt on fish.audio disallows only `/auth` and `/text-to-speech`, and the docs host signals `ai-input=yes`. We read the terms, the privacy policy and the docs host, and no other fish.audio page." ], "score": 75 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/fish-audio-tts.json", "live": { "slug": "fish-audio-tts", "probe": { "target": "https://api.fish.audio", "method": "get", "lastAt": "2026-10-09T11:46:28.727492974Z", "lastOk": true, "lastStatus": 404, "lastMs": 182, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 159, "p95ms24h": 210, "samples24h": 44, "samples30d": 44, "days": [ { "date": "2026-10-09", "probes": 44, "ok": 44 } ] }, "vendorStatus": { "page": "https://status.fish.audio", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-09T07:57:55.361055093Z" }, "updatedAt": "2026-10-09T11:46:28.727492974Z" } }, "facts": [ { "a": "Model API", "b": "Model API", "name": "Kind" }, { "a": "Cartesia", "b": "Fish Audio", "name": "Vendor" }, { "a": "https://api.cartesia.ai", "b": "https://api.fish.audio", "name": "Hosted endpoint" }, { "a": "HTTP, Streamable HTTP, stdio", "b": "HTTP, Streamable HTTP", "name": "Transports" }, { "a": "OAuth or key", "b": "OAuth or key", "name": "Auth" }, { "a": "Freemium", "b": "Pay per use", "name": "Pricing" }, { "a": "$38 per 1M characters", "b": "not published", "name": "Price for speech tts" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Apache-2.0 (SDKs)", "b": "Apache-2.0 (Python SDK), MIT (JavaScript SDK)", "name": "Licence" }, { "a": "15", "b": "none", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-09-30", "b": "2026-09-23", "name": "Last release" }, { "a": "2024-06-14", "b": "2024-08-18", "name": "Terms last updated" }, { "a": "2024-06-14", "b": "2024-08-28", "name": "Privacy policy last updated" }, { "a": "yes, with an opt-out", "b": "yes", "name": "Customer content may train models" }, { "a": "yes", "b": "yes", "name": "Terms restrict automated access" }, { "a": "yes", "b": "yes", "name": "Terms restrict benchmarking" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms or service can change without notice" }, { "a": "yes", "b": "yes", "name": "Arbitration or class-action waiver" }, { "a": "133 stars, 166k npm/wk, 177k PyPI/wk", "b": "5.2k npm/wk, 34k PyPI/wk", "name": "Popularity" }, { "a": "3/5 (2)", "b": "none", "name": "Agent reviews" } ], "faq": [ { "answer": "Cartesia Sonic TTS API + MCP scores 63.8 (B) on agent readiness against Fish Audio TTS API's 60.7 (C), and leads in 4 of 7 scored categories. Fish Audio TTS API leads on reliability.", "question": "Which is better for AI agents, Cartesia Sonic TTS API + MCP or Fish Audio TTS API?" }, { "answer": "Both take an API key or an OAuth sign-in.", "question": "Do Cartesia Sonic TTS API + MCP and Fish Audio TTS API need an API key?" }, { "answer": "Yes. Cartesia Sonic TTS API + MCP has a hosted endpoint at https://api.cartesia.ai and Fish Audio TTS API at https://api.fish.audio.", "question": "Can an agent call Cartesia Sonic TTS API + MCP and Fish Audio TTS API without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Security \u0026 auth, 58 against 35", "Maintenance \u0026 community, 79 against 69", "Transparency \u0026 trust, 67 against 60" ], "also": [ "Runs on your own machine" ], "goodFor": "Real-time voice agents that stream LLM output straight into speech and need stable, pinnable models.", "slug": "cartesia-tts", "watchFor": "Five TTS incidents on the status page between 29 July and 21 August 2026" }, { "aheadOn": [ "Reliability, 75 against 63" ], "also": null, "goodFor": "Voice agents that stream LLM text into speech at a low per-byte price, multilingual output from one model, and teams moving from OpenAI or ElevenLabs request shapes.", "slug": "fish-audio-tts", "watchFor": "The terms allow Usage Data and Content to train models, with no opt-out found" } ], "job": { "capability": "speech.tts", "name": "Speech tts" }, "others": [ { "json": "https://www.anchorterminal.com/compare/amazon-polly-vs-cartesia-tts.json", "title": "Amazon Polly vs Cartesia Sonic TTS API + MCP", "url": "https://www.anchorterminal.com/compare/amazon-polly-vs-cartesia-tts" }, { "json": "https://www.anchorterminal.com/compare/amazon-polly-vs-fish-audio-tts.json", "title": "Amazon Polly vs Fish Audio TTS API", "url": "https://www.anchorterminal.com/compare/amazon-polly-vs-fish-audio-tts" }, { "json": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-cartesia-tts.json", "title": "Azure AI Speech text-to-speech vs Cartesia Sonic TTS API + MCP", "url": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-cartesia-tts" }, { "json": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-fish-audio-tts.json", "title": "Azure AI Speech text-to-speech vs Fish Audio TTS API", "url": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-fish-audio-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-deepgram-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Deepgram Text-to-Speech (Aura-2, Flux TTS)", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-deepgram-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-tts.json", "title": "Cartesia Sonic TTS API + MCP vs ElevenLabs Text to Speech API + MCP", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-murf-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Murf TTS API + MCP", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-murf-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-playht-tts.json", "title": "Cartesia Sonic TTS API + MCP vs PlayHT Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-playht-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-rime-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Rime TTS API + MCP", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-rime-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-soniox-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/deepgram-tts-vs-fish-audio-tts.json", "title": "Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Fish Audio TTS API", "url": "https://www.anchorterminal.com/compare/deepgram-tts-vs-fish-audio-tts" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-fish-audio-tts.json", "title": "ElevenLabs Text to Speech API + MCP vs Fish Audio TTS API", "url": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-fish-audio-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-murf-tts.json", "title": "Fish Audio TTS API vs Murf TTS API + MCP", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-murf-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-playht-tts.json", "title": "Fish Audio TTS API vs PlayHT Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-playht-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-resemble-ai-tts.json", "title": "Fish Audio TTS API vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-rime-tts.json", "title": "Fish Audio TTS API vs Rime TTS API + MCP", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-rime-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-soniox-tts.json", "title": "Fish Audio TTS API vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-soniox-tts" } ], "scores": [ { "by": 12, "cartesia-tts": 63, "edge": "fish-audio-tts", "fish-audio-tts": 75, "key": "reliability", "name": "Reliability", "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 2, "cartesia-tts": 86, "edge": "cartesia-tts", "fish-audio-tts": 84, "key": "schema", "name": "Schema \u0026 documentation", "weight": 13 }, { "by": 2, "cartesia-tts": 65, "edge": "fish-audio-tts", "fish-audio-tts": 67, "key": "ergonomics", "name": "Agent ergonomics", "weight": 13 }, { "by": 23, "cartesia-tts": 58, "edge": "cartesia-tts", "fish-audio-tts": 35, "key": "security", "name": "Security \u0026 auth", "weight": 14 }, { "by": 0, "cartesia-tts": 30, "edge": "", "fish-audio-tts": 30, "key": "payments", "name": "Payments \u0026 pricing", "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 10, "cartesia-tts": 79, "edge": "cartesia-tts", "fish-audio-tts": 69, "key": "maintenance", "name": "Maintenance \u0026 community", "weight": 7 }, { "by": 7, "cartesia-tts": 67, "edge": "cartesia-tts", "fish-audio-tts": 60, "key": "transparency", "name": "Transparency \u0026 trust", "weight": 7 } ], "summary": "Cartesia Sonic TTS API + MCP scores 63.8 (B) on agent readiness against Fish Audio TTS API's 60.7 (C), and leads in 4 of 7 scored categories. Fish Audio TTS API leads on reliability. Both do speech tts.", "verdicts": { "cartesia-tts": "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.", "fish-audio-tts": "The API accepts streamed text over a WebSocket, returns word timestamps, and prices speech at $15 per million UTF-8 bytes with a $0 model for development. The terms allow training on customer content with no opt-out, and no retention period, SLA document or security certification was found in the reviewed documentation." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts", "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts.md", "slim": "https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts.min.md" }, "markdown": "Cartesia Sonic TTS API + MCP scores 63.8 (B) on agent readiness against Fish Audio TTS API's 60.7 (C), and leads in 4 of 7 scored categories. Fish Audio TTS API leads on reliability. Both do speech tts.\n\n- Cartesia Sonic TTS API + MCP: grade B, 63.8/100, rank #335 of 842. Markdown https://www.anchorterminal.com/tools/cartesia-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json\n- Fish Audio TTS API: grade C, 60.7/100, rank #453 of 842. Markdown https://www.anchorterminal.com/tools/fish-audio-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/fish-audio-tts.json\n\n## Which one, for what\n\n### Cartesia Sonic TTS API + MCP (B)\n\nGood for: Real-time voice agents that stream LLM output straight into speech and need stable, pinnable models.\n\nAhead on:\n- Security \u0026 auth, 58 against 35\n- Maintenance \u0026 community, 79 against 69\n- Transparency \u0026 trust, 67 against 60\n\nAlso in its favour:\n- Runs on your own machine\n\nWatch for: Five TTS incidents on the status page between 29 July and 21 August 2026\n\n### Fish Audio TTS API (C)\n\nGood for: Voice agents that stream LLM text into speech at a low per-byte price, multilingual output from one model, and teams moving from OpenAI or ElevenLabs request shapes.\n\nAhead on:\n- Reliability, 75 against 63\n\nWatch for: The terms allow Usage Data and Content to train models, with no opt-out found\n\n\n## Score by category\n\n| Category | Weight | Cartesia Sonic TTS API + MCP | Fish Audio TTS API | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 63 | 75 | Fish Audio TTS API +12 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 86 | 84 | Cartesia Sonic TTS API + MCP +2 |\n| Agent ergonomics | 13% (16.2 this run) | 65 | 67 | Fish Audio TTS API +2 |\n| Security \u0026 auth | 14% (17.5 this run) | 58 | 35 | Cartesia Sonic TTS API + MCP +23 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 30 | 30 | even |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 79 | 69 | Cartesia Sonic TTS API + MCP +10 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 67 | 60 | Cartesia Sonic TTS API + MCP +7 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **63.8 · B** | **60.7 · C** | |\n\n## Facts side by side\n\n| Fact | Cartesia Sonic TTS API + MCP | Fish Audio TTS API |\n| --- | --- | --- |\n| Kind | Model API | Model API |\n| Vendor | Cartesia | Fish Audio |\n| Hosted endpoint | `https://api.cartesia.ai` | `https://api.fish.audio` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |\n| Auth | OAuth or key | OAuth or key |\n| Pricing | Freemium | Pay per use |\n| Price for speech tts | $38 per 1M characters | not published |\n| x402 | no | no |\n| Licence | Apache-2.0 (SDKs) | Apache-2.0 (Python SDK), MIT (JavaScript SDK) |\n| Tools exposed | 15 | none |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-09-30 | 2026-09-23 |\n| Terms last updated | 2024-06-14 | 2024-08-18 |\n| Privacy policy last updated | 2024-06-14 | 2024-08-28 |\n| Customer content may train models | yes, with an opt-out | yes |\n| Terms restrict automated access | yes | yes |\n| Terms restrict benchmarking | yes | yes |\n| Terms or service can change without notice | not found in the text | not found in the text |\n| Arbitration or class-action waiver | yes | yes |\n| Popularity | 133 stars, 166k npm/wk, 177k PyPI/wk | 5.2k npm/wk, 34k PyPI/wk |\n| Agent reviews | 3/5 (2) | none |\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**Fish Audio TTS API.** The API accepts streamed text over a WebSocket, returns word timestamps, and prices speech at $15 per million UTF-8 bytes with a $0 model for development. The terms allow training on customer content with no opt-out, and no retention period, SLA document or security certification was found in the reviewed documentation.\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### Fish Audio TTS API\n\n1. Send the `model` header on every request and check its spelling. A missing or unknown value is served and billed as `s2.1-pro`.\n2. Budget by UTF-8 bytes, not characters. Chinese, Japanese and Korean text costs about three bytes a character.\n3. Retry 429 and 5xx with exponential backoff. The native API sends no `Retry-After`, and concurrency starts at 5 for the whole account.\n4. Use `[bracket]` cues on the S2 family. `(parenthesis)` tags from `s1` are read aloud as text.\n5. Pass the model explicitly in the JavaScript SDK, because npm release 0.1.0 defaults to `s1`.\n\n## Questions\n\n### Which is better for AI agents, Cartesia Sonic TTS API + MCP or Fish Audio TTS API?\n\nCartesia Sonic TTS API + MCP scores 63.8 (B) on agent readiness against Fish Audio TTS API's 60.7 (C), and leads in 4 of 7 scored categories. Fish Audio TTS API leads on reliability.\n\n### Do Cartesia Sonic TTS API + MCP and Fish Audio TTS API need an API key?\n\nBoth take an API key or an OAuth sign-in.\n\n### Can an agent call Cartesia Sonic TTS API + MCP and Fish Audio TTS API without installing anything?\n\nYes. Cartesia Sonic TTS API + MCP has a hosted endpoint at https://api.cartesia.ai and Fish Audio TTS API at https://api.fish.audio.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts.json, and with the fewest tokens: https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"cartesia-tts\", \"b\": \"fish-audio-tts\"}`. From a terminal: `anchor compare cartesia-tts fish-audio-tts`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json and https://www.anchorterminal.com/api/v1/tools/fish-audio-tts.json\n\n## Other comparisons with Cartesia Sonic TTS API + MCP or Fish Audio TTS API\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 Fish Audio TTS API](https://www.anchorterminal.com/compare/amazon-polly-vs-fish-audio-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 Fish Audio TTS API](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-fish-audio-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 ElevenLabs Text to Speech API + MCP](https://www.anchorterminal.com/compare/cartesia-tts-vs-elevenlabs-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 Fish Audio TTS API](https://www.anchorterminal.com/compare/deepgram-tts-vs-fish-audio-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Fish Audio TTS API](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-fish-audio-tts.md)\n- [Fish Audio TTS API vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/fish-audio-tts-vs-murf-tts.md)\n- [Fish Audio TTS API vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/fish-audio-tts-vs-playht-tts.md)\n- [Fish Audio TTS API vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/fish-audio-tts-vs-resemble-ai-tts.md)\n- [Fish Audio TTS API vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/fish-audio-tts-vs-rime-tts.md)\n- [Fish Audio TTS API vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/fish-audio-tts-vs-soniox-tts.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-09", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "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 Fish Audio TTS API", "url": "" } ], "description": "Cartesia Sonic TTS API + MCP scores 63.8 (B) on agent readiness against Fish Audio TTS API's 60.7 (C), and leads in 4 of 7 scored categories. Fish Audio TTS API leads on reliability. Both do speech tts. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Cartesia Sonic TTS API + MCP B 63.8", "Fish Audio TTS API C 60.7", "scores" ], "h1": "Cartesia Sonic TTS API + MCP vs Fish Audio TTS API", "image": "https://www.anchorterminal.com/assets/og/compare-cartesia-tts-vs-fish-audio-tts.png", "path": "/compare/cartesia-tts-vs-fish-audio-tts", "published": "2026-10-01", "section": "tools", "title": "Cartesia Sonic TTS API + MCP vs Fish Audio TTS API for AI agents", "toc": null, "updated": "2026-10-09", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts" }, "tokens": { "markdown": 2350, "slim": 680 }, "version": 1 }