{ "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", "dns": "cartesia-tts.grade.anchorterminal.com", "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", "main": true }, { "registry": "pypi", "name": "cartesia", "main": true }, { "registry": "pypi", "name": "cartesia-mcp", "main": true } ], "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": 19, "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": "2026-10-30", "graded": true, "anchor": { "graded": true, "score": 61.9, "grade": "C", "agentReady": false, "rank": 582, "ranked": true, "rankOf": 1486, "categoryRank": 10, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 65, "maintenance": 84, "payments": 30, "reliability": 73, "schema": 86, "security": 47, "transparency": 73 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-02" }, "negative": -3, "negativeNotes": [ "September 2026 (dated by month only; the SDKs added `case_sensitive` on 2 September). Pronunciation dictionaries on Sonic 3.6 \"now ignore case by default\", so an existing entry starts matching other capitalisations and the audio for existing callers changes with no code change, and the API now rejects entries that collide under the new rule. No earlier notice was found in the changelog, so this run's same-day term applies (-3) (https://docs.cartesia.ai/changelog/2026)." ], "verdict": "The WebSocket accepts streamed LLM text with contexts, flushing and word timestamps, and dated Sonic snapshots never change. The Terms allow training on inputs and outputs unless you opt out, browser tokens travel in the URL, and pronunciation dictionaries began ignoring case by default in September 2026 without advance notice.", "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, with Sonic-2 and Sonic Turbo sunset after 20 October 2026 on about 83 days' notice" ], "weaknesses": [ "Pronunciation dictionaries on Sonic 3.6 began ignoring case by default in September 2026, with no earlier notice found", "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", "Browser clients pass the access token as a WebSocket query parameter" ], "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.", "Use `sonic-3.6` or a dated `sonic-3.6-*` snapshot. `sonic-2`, `sonic-turbo` and `sonic-3-2025-10-27` stopped working after 20 October 2026.", "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.", "Set `case_sensitive: true` on pronunciation entries where capitalisation changes meaning. Entries default to case-insensitive on Sonic 3.6." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 61.9 } ], "editorialScores": { "ergonomics": 65, "maintenance": 84, "payments": 30, "reliability": 73, "schema": 86, "security": 47, "transparency": 60 }, "provenanceScore": 86, "checked": { "categories": { "ergonomics": "2026-11-02", "maintenance": "2026-11-02", "payments": "2026-11-02", "reliability": "2026-11-02", "schema": "2026-11-02", "security": "2026-11-02", "transparency": "2026-11-02" }, "last": "2026-11-02", "lastMoved": "2026-11-02", "oldest": "2026-11-02", "stale": false, "staleAfterDays": 90 } }, "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-ink-stt", "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": "valid", "checked": "2026-11-02", "notes": [ "www.cartesia.ai/.well-known/security.txt answered on 2026-11-02 with a contact, a policy link to trust.cartesia.ai and Expires 2027-10-03.", "status.cartesia.ai is an incident.io page; its robots.txt answers an HTML 404 page (no rules)." ], "score": 86 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/cartesia-tts.json", "live": { "slug": "cartesia-tts", "probe": { "target": "https://api.cartesia.ai", "method": "get", "lastAt": "2026-11-07T18:20:16.163517449Z", "lastOk": true, "lastStatus": 200, "lastMs": 60, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 53, "p95ms24h": 131, "samples24h": 239, "samples30d": 7910, "days": [ { "date": "2026-10-07", "probes": 272, "ok": 272 }, { "date": "2026-10-08", "probes": 268, "ok": 268 }, { "date": "2026-10-09", "probes": 250, "ok": 250 }, { "date": "2026-10-10", "probes": 247, "ok": 247 }, { "date": "2026-10-11", "probes": 247, "ok": 247 }, { "date": "2026-10-12", "probes": 247, "ok": 247 }, { "date": "2026-10-13", "probes": 248, "ok": 248 }, { "date": "2026-10-14", "probes": 249, "ok": 249 }, { "date": "2026-10-15", "probes": 253, "ok": 253 }, { "date": "2026-10-16", "probes": 252, "ok": 252 }, { "date": "2026-10-17", "probes": 253, "ok": 253 }, { "date": "2026-10-18", "probes": 256, "ok": 256 }, { "date": "2026-10-19", "probes": 255, "ok": 255 }, { "date": "2026-10-20", "probes": 252, "ok": 252 }, { "date": "2026-10-21", "probes": 253, "ok": 253 }, { "date": "2026-10-22", "probes": 253, "ok": 253 }, { "date": "2026-10-23", "probes": 248, "ok": 248 }, { "date": "2026-10-24", "probes": 251, "ok": 251 }, { "date": "2026-10-25", "probes": 250, "ok": 250 }, { "date": "2026-10-26", "probes": 252, "ok": 252 }, { "date": "2026-10-27", "probes": 249, "ok": 249 }, { "date": "2026-10-28", "probes": 251, "ok": 251 }, { "date": "2026-10-29", "probes": 249, "ok": 249 }, { "date": "2026-10-30", "probes": 248, "ok": 248 }, { "date": "2026-10-31", "probes": 251, "ok": 251 }, { "date": "2026-11-01", "probes": 249, "ok": 249 }, { "date": "2026-11-02", "probes": 250, "ok": 250 }, { "date": "2026-11-03", "probes": 248, "ok": 248 }, { "date": "2026-11-04", "probes": 246, "ok": 246 }, { "date": "2026-11-05", "probes": 185, "ok": 185 }, { "date": "2026-11-06", "probes": 241, "ok": 241 }, { "date": "2026-11-07", "probes": 187, "ok": 187 } ] }, "vendorStatus": { "page": "https://status.cartesia.ai", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-11-07T18:20:38.07161798Z" }, "versions": [ { "registry": "github", "name": "cartesia-ai/cartesia-python", "version": "v4.2.0", "released": "2026-09-02", "seenAt": "2026-11-06T23:13:26.405806168Z" }, { "registry": "npm", "name": "@cartesia/cartesia-js", "version": "4.2.0", "seenAt": "2026-11-06T23:13:24.187943574Z" }, { "registry": "pypi", "name": "cartesia", "version": "4.2.0", "released": "2026-09-02", "seenAt": "2026-11-06T23:13:24.399324036Z" }, { "registry": "pypi", "name": "cartesia-mcp", "version": "0.29.0", "released": "2026-11-05", "seenAt": "2026-11-06T23:13:24.506276643Z" } ], "githubStars": 139, "npmWeekly": 105860, "pypiWeekly": 241069, "securityTxt": { "url": "https://cartesia.ai/.well-known/security.txt", "state": "valid", "expires": "2027-10-03T00:00:00.000Z", "checkedAt": "2026-11-07T16:01:22.207018558Z" }, "llmsTxt": { "url": "https://docs.cartesia.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:31:50.167568829Z" }, "domain": { "domain": "cartesia.ai", "registered": "2023-05-10", "source": "https://rdap.identitydigital.services/rdap/domain/cartesia.ai", "checkedAt": "2026-11-01T14:10:04.149838535Z" }, "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": "2026-11-07T14:00:46.648388282Z", "changedAt": "2026-11-07T14:00:46.648388282Z", "fingerprint": "3a338414361a" }, { "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" } ], "github": { "repo": "cartesia-ai/cartesia-python", "checkedAt": "2026-11-02T08:37:37.378374658Z", "stars": 138, "archived": false, "issuesEnabled": true, "pushedAt": "2026-10-30T18:24:19Z", "openIssues": 1, "openPRs": 8, "issuesOpened90d": 1, "issuesClosed90d": 1, "prsMerged90d": 4, "ci": { "branch": "main", "runs": 50, "success": 33, "failure": 0, "other": 17, "latest": "skipped", "latestAt": "2026-10-23T17:43:01Z" }, "replies": { "sampled": 14, "unanswered": 1, "medianDays": 54.7 } }, "updatedAt": "2026-11-07T18:20:16.163517449Z" } }, "answer": "Cartesia Sonic TTS API + MCP scores 61.9 (C) on agent readiness against MiniMax Speech (T2A)'s 55.1 (C), and leads in 6 of 7 scored categories.", "b": { "slug": "minimax-speech", "name": "MiniMax Speech (T2A)", "vendor": "MiniMax", "vendorUrl": "https://www.minimax.io", "kind": "model", "category": "text-to-speech", "summary": "MiniMax's text-to-speech API synthesises speech with its speech-2.8 HD and Turbo models over HTTP with optional streaming, WebSocket (including bidirectional text streaming) and an asynchronous long-text API, with 300+ system voices, pronunciation dictionaries and subtitles.", "url": "https://www.anchorterminal.com/tools/minimax-speech", "markdownUrl": "https://www.anchorterminal.com/tools/minimax-speech.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/minimax-speech.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/minimax-speech.json", "dns": "minimax-speech.grade.anchorterminal.com", "transports": [ "http", "websocket" ], "packages": [ { "registry": "pypi", "name": "minimax-mcp" }, { "registry": "npm", "name": "minimax-mcp-js" } ], "auth": "api-key", "authNotes": "Bearer API key created in the platform console under Account, API Keys. No scopes were found in the docs. Mainland China accounts use `https://api.minimaxi.com`.", "pricing": "usage", "pricingNotes": "Pay as you go from a prepaid balance. speech-2.8-hd costs $100 and speech-2.8-turbo $60 per million characters, on the sync and async APIs alike. Audio subscriptions from $5 a month add voice slots and higher request rates. No free allowance is published for speech synthesis.", "priceSummary": "Pay per use", "where": "local", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs, OpenAPI and AsyncAPI files or pricing page (checked 2026-11-06).", "endpoints": [] }, "toolCount": 0, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-11-06" }, "docsUrl": "https://platform.minimax.io/docs/api-reference/speech-t2a-http", "llmsTxt": "https://platform.minimax.io/docs/llms.txt", "openapi": "https://platform.minimax.io/docs/api-reference/speech/t2a/api/openapi.json", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.languages" ], "tags": [ "official", "hosted", "usage-priced", "prepaid", "openapi", "llms-txt", "mcp", "python", "typescript", "status-page" ], "lastRelease": "2026-01-23", "graded": true, "anchor": { "graded": true, "score": 55.1, "grade": "C", "agentReady": false, "rank": 879, "ranked": true, "rankOf": 1486, "categoryRank": 13, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 56, "maintenance": 38, "payments": 20, "reliability": 75, "schema": 81, "security": 36, "transparency": 65 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-06" }, "negative": 0, "verdict": "MiniMax's speech API covers sync, WebSocket, bidirectional and async synthesis with OpenAPI and AsyncAPI files and public prices of $60 to $100 per million characters. Text-to-Speech had only short incidents in 90 days. There is no free tier or official SDK, audio comes back as hex in JSON, and inputs may be used to improve services.", "bestFor": "Multilingual speech for narration and agents at mid-range prices, with strong Chinese voices by the vendor's account.", "strengths": [ "OpenAPI files for sync and async synthesis and AsyncAPI files for both sockets", "Statuspage with a Text-to-Speech component; three incidents in 90 days, the longest 22 minutes", "Public prices of $60 (Turbo) and $100 (HD) per million characters on sync and async alike", "Pronunciation dictionaries, pause markers, timbre mixing and subtitles", "Official MCP servers in Python and JavaScript with a speech tool" ], "weaknesses": [ "No free allowance for synthesis and no official SDK", "Sync responses carry audio as hex inside JSON, and the OpenAPI file documents only a 200 response", "API release notes stop at 28 October 2025, and the newest speech model dates from January 2026", "Terms let MiniMax use inputs to improve its services with no opt-out, and no retention period is published", "No security.txt, disclosure policy or certification found" ], "agentNotes": [ "Keep sync requests under 10,000 characters and use the async API for longer text", "Decode the hex `audio` field before saving, or stream for text over 3,000 characters", "Check `base_resp.status_code` on every response, since errors arrive inside a 200", "Stay under 60 requests a minute and back off on code 1002", "Use speech-2.8-turbo for agents and HD only where quality matters, since HD costs two thirds more" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 55.1 } ], "editorialScores": { "ergonomics": 56, "maintenance": 38, "payments": 20, "reliability": 75, "schema": 81, "security": 36, "transparency": 48 }, "provenanceScore": 82, "checked": { "categories": { "ergonomics": "2026-11-06", "maintenance": "2026-11-06", "payments": "2026-11-06", "reliability": "2026-11-06", "schema": "2026-11-06", "security": "2026-11-06", "transparency": "2026-11-06" }, "last": "2026-11-06", "oldest": "2026-11-06", "stale": false, "staleAfterDays": 90 } }, "connect": { "http": "curl -X POST https://api.minimax.io/v1/t2a_v2 \\\n -H \"Authorization: Bearer $MINIMAX_API_KEY\" -H \"Content-Type: application/json\" \\\n -d '{\"model\": \"speech-2.8-turbo\", \"text\": \"Hello from MiniMax.\", \"voice_setting\": {\"voice_id\": \"English_expressive_narrator\"}}'" }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/minimax-speech" }, "sameCompany": [ "minimax-api", "minimax-video", "minimax-stt", "minimax-voice-cloning", "minimax-code", "minimax-m2-5", "minimax-m2-7", "minimax-m3-1-flash" ], "area": "voice", "unitPrices": [ { "item": "speech-2.8-hd", "unit": "1m-chars", "usd": 100, "note": "sync and async" }, { "item": "speech-2.8-turbo", "unit": "1m-chars", "usd": 60, "note": "sync and async" } ], "provenance": { "legalEntity": "Nanonoble Pte. Ltd.", "domain": "minimax.io", "domainRegistered": "2021-03-27", "endpointOnVendorDomain": true, "terms": "https://platform.minimax.io/protocol/terms-of-service", "privacy": "https://platform.minimax.io/protocol/privacy-policy", "statusPage": "https://status.minimax.io", "changelog": "https://platform.minimax.io/docs/release-notes/apis", "securityTxt": "none", "checked": "2026-11-06", "notes": [ "Nanonoble Pte. Ltd., 152 Beach Road, #14-02 Gateway East, Singapore, is named in the terms (effective 30 March 2026) and the privacy policy (updated 30 March 2026), read on 4 November 2026 from the document text the pages carry for the browser, as on the minimax-api listing. The 8 October reader recorded both pages as unreadable.", "RDAP for minimax.io gives a registration date of 2021-03-27 and a transfer on 2025-01-31, as recorded on 8 October.", "platform.minimax.io/.well-known/security.txt returns 404 (per the 8 October check), and www.minimax.io/.well-known/security.txt redirects to the home page.", "The API release notes page has no entry after 28 October 2025 on 4 November. Model releases are dated on a separate page, whose newest speech model is Speech 2.8 (23 January 2026).", "status.minimax.io/robots.txt disallows /api/, so incidents were read from the /history pages only.", "firstReleased is left empty. lastRelease is Speech 2.8, dated 23 January 2026 on the model release page." ], "score": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/minimax-speech.json", "live": { "slug": "minimax-speech", "vendorStatus": { "page": "https://status.minimax.io", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-11-07T18:21:22.955290584Z" }, "versions": [ { "registry": "npm", "name": "minimax-mcp-js", "version": "0.0.18", "seenAt": "2026-11-06T23:46:02.528010346Z" }, { "registry": "pypi", "name": "minimax-mcp", "version": "0.0.19", "released": "2026-08-21", "seenAt": "2026-11-06T23:46:02.341494165Z" } ], "npmWeekly": 493, "pypiWeekly": 2443, "securityTxt": { "url": "https://minimax.io/.well-known/security.txt", "state": "none", "checkedAt": "2026-11-07T16:00:57.120551174Z" }, "llmsTxt": { "url": "https://platform.minimax.io/docs/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:33:04.532998601Z" }, "pages": [ { "url": "https://platform.minimax.io/docs/release-notes/apis", "kind": "changelog", "status": 200, "checkedAt": "2026-11-07T14:16:49.741417545Z", "changedAt": "2026-11-05T12:39:36.530148547Z", "fingerprint": "dc39bde39ad3" } ], "updatedAt": "2026-11-07T18:21:22.955290584Z" } }, "edges": [ { "by": 46, "category": "maintenance", "leads": "cartesia-tts", "name": "Maintenance \u0026 community", "reasons": { "a": "Read as a model, on the lines deepgram-tts, gladia-stt and cartesia-ink-stt use for hosted speech models (recency 30, dated releases 10, deprecation notice 10, support 15, issues 10, SDKs 15, health 10). `cartesia-mcp`, whose `text_to_speech` tool calls Sonic, released 0.28.1 on 30 October 2026 after 0.27.0 (20 October), 0.27.1 (23 October) and 0.28.0 (27 October), and `sonic-3.6-2026-08-27` is the newest snapshot (30). From 4 August the Python and TypeScript SDKs released 4.0.0, 4.0.1, 4.1.0 and 4.2.0 (14 August to 2 September) and the MCP server more than ten releases (10). Sonic-2, Sonic Turbo and `sonic-3-2025-10-27` were sunset after 20 October 2026, announced in the July changelog, about 83 days ahead. The deprecations page dates each sunset but states no minimum notice period (5 of 10). The changelog has Text-to-Speech entries every month from May to September 2026, dated by month only, and no October entry, the same reading as cartesia-ink-stt (11 of 15; was 5). The Python SDK repository had 4 open issues on 9 October per the cartesia-ink-stt check, not re-read on 2 November since GitHub's pages answered 403 (5 of 10; was 7 on a 1 October count of one). Official `cartesia` and `@cartesia/cartesia-js` SDKs at 4.2.0 (2 September 2026), generated for API version 2026-08-14 (15). CI, release-please and lock files in both SDK repositories, with dependency updates merged on 23 October (8 of 10). 30+10+5+11+5+15+8 = 84.", "b": "Read as a model, as minimax-voice-cloning is. The newest dated change touching speech is the MCP servers' August update, `minimax-mcp-js` 0.0.18 on 21 August 2026, 77 days before 6 November, and Speech 2.8 dates from 23 January 2026 (20 of 30). No dated API entries in the last 90 days (0). Support by email and Discord, not tested (6 of 15). No official SDK for speech; the MCP servers expose `text_to_audio` and `list_voices` (8 of 15). The Python MCP server has tests and moved to version 2 of the MCP SDK in August, with no CI workflow (4 of 10). Total 38." }, "scores": { "a": 84, "b": 38 } }, { "by": 11, "category": "security", "leads": "cartesia-tts", "name": "Security \u0026 auth", "reasons": { "a": "Model reading of the checklist (credential, training, retention, operator visibility, programme), on the same evidence and values as cartesia-ink-stt. Standard and admin API keys are separate types, revocable, and a server can mint short-lived access tokens with TTS, STT and agent grants, but no key is scoped to TTS (26). Browsers pass the access token in the WebSocket query string, which the authentication guide documents (\"In browsers, use an access token and query parameters instead\"), and this run takes the full 10 off for a reusable token in a URL, as for cartesia-ink-stt and every Google API listing (16 of 30; the 1 October check didn't deduct). The Terms (last revised 14 June 2024, re-read on 2 November) say inputs, outputs and interactions may be used to train models unless otherwise agreed, with an opt-out form (5 of 20, aligned with cartesia-ink-stt; was 10). Zero data retention is Enterprise only and no retention period is published for other plans (5 of 15). Credit usage and key metadata are readable through admin endpoints and the usage dashboard, no per-call audit log found (7 of 15, aligned; was 8). security.txt at www.cartesia.ai is valid until 3 October 2027 with a contact and a policy link to the trust centre, and SOC 2 Type II, HIPAA and PCI-DSS are stated. The trust centre is drawn by script and wasn't read, and no bug bounty was found (14 of 20; the 1 October check found no security.txt, 10). 16+5+5+7+14 = 47.", "b": "Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. Plain API keys with no scopes found, and leaked keys may be disabled (20 of 30). The terms (effective 30 March 2026), as read for minimax-voice-cloning on 4 November, let MiniMax use input and generated content to operate, maintain, develop and improve its services, with no opt-out found, and the privacy policy rules out only training to profile or target consumers (5 of 20). The speech docs call every interface stateless, and no retention period for submitted text or generated audio was found (5 of 15). Responses carry `usage_characters` and a trace ID, with no audit log (6 of 15). No security.txt, disclosure policy, bug bounty or certification found (0 of 20). Total 36." }, "scores": { "a": 47, "b": 36 } }, { "by": 10, "category": "payments", "leads": "cartesia-tts", "name": "Payments \u0026 pricing", "reasons": { "a": "No x402, MPP or L402 (0). Plan prices and credit allowances are public, about 1 credit a character, but there's no plain dollar price per character outside the plans (10). Free plan with 20,000 credits a month (about 27 minutes), no card step mentioned, non-commercial use only (20). A person signs up in a browser (0).", "b": "No x402, MPP or L402 (0). Per-character prices for every speech model published without a login (20). No free allowance for synthesis is published (0). A person signs up in a browser and funds a balance (0). Total 20." }, "scores": { "a": 30, "b": 20 } }, { "by": 9, "category": "ergonomics", "leads": "cartesia-tts", "name": "Agent ergonomics", "reasons": { "a": "API reading of the checklist. WAV, MP3 or raw PCM from 8 to 48 kHz, over bytes, SSE or a WebSocket that takes streamed LLM text, with word timestamps on request (22 of 25). Voice lists paginate with SDK iterators, filters not confirmed, and no per-request length cap is documented (10 of 20). Errors are HTTP statuses mapped to SDK exceptions without TTS-specific codes (10 of 20). The SDK retries 429 and 5xx with backoff. We found no seed and didn't confirm the billing rule for failed calls (10 of 20). Four required fields plus the version header, and official Python and TypeScript SDKs (13 of 15).", "b": "API reading of the checklist. Audio comes back hex-encoded inside JSON by default, with subtitles opt-in and format, bitrate and sample rate settable (15 of 25). Voices are listed by type through `POST /v1/get_voice`, which has no pagination and returns 300+ system voices for `all` (10 of 20). Errors come as numeric codes in `base_resp` with a short remedy for each, inside responses documented only as 200 (13 of 20). No idempotency key, and the MCP tools carry no read-only or destructive annotations (10 of 20). Two required fields. No official SDK for speech, with MCP servers in Python and JavaScript (8 of 15). Total 56." }, "scores": { "a": 65, "b": 56 } }, { "by": 8, "category": "transparency", "leads": "cartesia-tts", "name": "Transparency \u0026 trust", "reasons": { "a": "Closed service with clear terms, SDKs under Apache-2.0 (15). Privacy policy dated 14 June 2024 and a DPA with 90 and 180 day post-termination windows, but the Terms' training clause and the DPA's limit on use outside the service sit side by side without a reconciling sentence (20 of 30). Dated deprecation notices in the changelog, no written notice policy (15 of 20). Sub-processors sit behind the trust centre, which we couldn't read without a browser. Regional status components for the US, EU, APAC and Australia (10 of 20).", "b": "Closed API with clear terms under Singapore law naming Nanonoble Pte. Ltd., and MIT MCP servers (15 of 30). Terms and privacy policy agree that inputs may be used to improve services and that data sits in a United States data centre, with no retention period, as on minimax-voice-cloning (8 of 30). The API release notes carry a dated legacy notice of 20 June 2025 for the old text-to-voice API with service continuing, and older speech models stay accepted, with no written policy or notice period (15 of 20). Data location stated as the United States and an EU representative named, third parties only by category (10 of 20). Total 48." }, "scores": { "a": 73, "b": 65 } }, { "by": 5, "category": "schema", "leads": "cartesia-tts", "name": "Schema \u0026 documentation", "reasons": { "a": "OpenAPI files for the latest and each dated API version, plus AsyncAPI files for the WebSocket, are listed in llms.txt (25). llms.txt and Markdown pages (10). A page compares the bytes, SSE and WebSocket endpoints and says which to use for what, and model pages explain dated snapshots (15 of 20). Typed request bodies with enums for container, encoding and sample rate, and a 0.6 to 1.5 range on `speed` (13 of 15). Examples in curl and both SDKs, but no error responses documented for the TTS endpoints, only SDK exception classes (8 of 15). Dated `Cartesia-Version` header, dated model snapshots that never change, and a monthly changelog (15).", "b": "OpenAPI 3.1 for the sync and async routes and AsyncAPI files for the WebSocket and bidirectional sockets (25). llms.txt and a Markdown copy of every page (10). The text field says when to stream and how to mark pauses, and guides separate sync, WebSocket and async use (15 of 20). Enums for model and audio settings, with `model` and `text` required (13 of 15). Examples throughout and the shared table of error codes, but the OpenAPI file documents only a 200 response (10 of 15). Versioned `/v1` paths. The API release notes stop at 28 October 2025, and the last T2A entry is 23 September 2025 (8 of 15). Total 81." }, "scores": { "a": 86, "b": 81 } } ], "facts": [ { "a": "Model API", "b": "Model API", "name": "Kind" }, { "a": "Cartesia", "b": "MiniMax", "name": "Vendor" }, { "a": "https://api.cartesia.ai", "b": "no (local only)", "name": "Hosted endpoint" }, { "a": "HTTP, Streamable HTTP, stdio", "b": "HTTP, websocket", "name": "Transports" }, { "a": "OAuth or key", "b": "API key", "name": "Auth" }, { "a": "Freemium", "b": "Pay per use", "name": "Pricing" }, { "a": "$38 per 1M characters", "b": "not published", "name": "Price for text-to-speech" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Apache-2.0 (SDKs)", "b": "none", "name": "Licence" }, { "a": "19", "b": "0", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-10-30", "b": "2026-01-23", "name": "Last release" }, { "a": "2024-06-14", "b": "couldn't be read", "name": "Terms last updated" }, { "a": "2024-06-14", "b": "couldn't be read", "name": "Privacy policy last updated" }, { "a": "yes, with an opt-out", "b": "couldn't be read", "name": "Customer content may train models" }, { "a": "yes", "b": "couldn't be read", "name": "Terms restrict automated access" }, { "a": "yes", "b": "couldn't be read", "name": "Terms restrict benchmarking" }, { "a": "not found in the text", "b": "couldn't be read", "name": "Terms or service can change without notice" }, { "a": "yes", "b": "couldn't be read", "name": "Arbitration or class-action waiver" }, { "a": "133 stars, 166k npm/wk, 177k PyPI/wk", "b": "none", "name": "Popularity" }, { "a": "3/5 (2)", "b": "none", "name": "Agent reviews" } ], "faq": [ { "answer": "Cartesia Sonic TTS API + MCP scores 61.9 (C) on agent readiness against MiniMax Speech (T2A)'s 55.1 (C), and leads in 6 of 7 scored categories.", "question": "Which is better for AI agents, Cartesia Sonic TTS API + MCP or MiniMax Speech (T2A)?" }, { "answer": "Cartesia Sonic TTS API + MCP takes an API key or an OAuth sign-in. MiniMax Speech (T2A) needs an API key.", "question": "Do Cartesia Sonic TTS API + MCP and MiniMax Speech (T2A) need an API key?" }, { "answer": "Cartesia Sonic TTS API + MCP has a hosted endpoint at https://api.cartesia.ai. No hosted endpoint is listed for MiniMax Speech (T2A).", "question": "Can an agent call Cartesia Sonic TTS API + MCP and MiniMax Speech (T2A) without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Schema \u0026 documentation, 86 against 81", "Agent ergonomics, 65 against 56", "Security \u0026 auth, 47 against 36", "Payments \u0026 pricing, 30 against 20", "Maintenance \u0026 community, 84 against 38", "Transparency \u0026 trust, 73 against 65" ], "also": [ "A hosted endpoint, with nothing to install", "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": "Pronunciation dictionaries on Sonic 3.6 began ignoring case by default in September 2026, with no earlier notice found" }, { "aheadOn": null, "also": [ "No incidents deducted, where Cartesia Sonic TTS API + MCP loses 3 points for them" ], "goodFor": "Multilingual speech for narration and agents at mid-range prices, with strong Chinese voices by the vendor's account.", "slug": "minimax-speech", "watchFor": "No free allowance for synthesis and no official SDK" } ], "history": { "cartesia-tts": [ { "causes": [ "evidence", "correction", "event" ], "date": "2026-11-02", "delta": -2.1, "from": 64, "fromGrade": "B", "to": 61.9, "toGrade": "C" }, { "causes": [ "method" ], "date": "2026-10-27", "delta": 0.2, "from": 63.8, "fromGrade": "B", "to": 64, "toGrade": "B" }, { "causes": [ "method" ], "date": "2026-10-08", "delta": -0.4, "from": 64.2, "fromGrade": "B", "to": 63.8, "toGrade": "B" } ], "minimax-speech": null }, "job": { "capability": "speech.tts", "name": "Text-to-speech" }, "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-minimax-speech.json", "title": "Amazon Polly vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/amazon-polly-vs-minimax-speech" }, { "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-minimax-speech.json", "title": "Azure AI Speech text-to-speech vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-minimax-speech" }, { "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-fish-audio-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Fish Audio TTS API", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-google-cloud-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Google Cloud Text-to-Speech", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-google-cloud-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-heygen-voice.json", "title": "Cartesia Sonic TTS API + MCP vs HeyGen Voice", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-heygen-voice" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-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-smallest-lightning-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-smallest-lightning-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-minimax-speech.json", "title": "Deepgram Text-to-Speech (Aura-2, Flux TTS) vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/deepgram-tts-vs-minimax-speech" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-minimax-speech.json", "title": "ElevenLabs Text to Speech API + MCP vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-minimax-speech" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-minimax-speech.json", "title": "Fish Audio TTS API vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-minimax-speech" }, { "json": "https://www.anchorterminal.com/compare/google-cloud-tts-vs-minimax-speech.json", "title": "Google Cloud Text-to-Speech vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/google-cloud-tts-vs-minimax-speech" }, { "json": "https://www.anchorterminal.com/compare/heygen-voice-vs-minimax-speech.json", "title": "HeyGen Voice vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/heygen-voice-vs-minimax-speech" }, { "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-minimax-speech.json", "title": "Inworld Realtime TTS-2 vs MiniMax Speech (T2A)", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-minimax-speech" }, { "json": "https://www.anchorterminal.com/compare/minimax-speech-vs-murf-tts.json", "title": "MiniMax Speech (T2A) vs Murf TTS API + MCP", "url": "https://www.anchorterminal.com/compare/minimax-speech-vs-murf-tts" }, { "json": "https://www.anchorterminal.com/compare/minimax-speech-vs-playht-tts.json", "title": "MiniMax Speech (T2A) vs PlayHT Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/minimax-speech-vs-playht-tts" }, { "json": "https://www.anchorterminal.com/compare/minimax-speech-vs-resemble-ai-tts.json", "title": "MiniMax Speech (T2A) vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/minimax-speech-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/minimax-speech-vs-rime-tts.json", "title": "MiniMax Speech (T2A) vs Rime TTS API + MCP", "url": "https://www.anchorterminal.com/compare/minimax-speech-vs-rime-tts" }, { "json": "https://www.anchorterminal.com/compare/minimax-speech-vs-smallest-lightning-tts.json", "title": "MiniMax Speech (T2A) vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/minimax-speech-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/minimax-speech-vs-soniox-tts.json", "title": "MiniMax Speech (T2A) vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/minimax-speech-vs-soniox-tts" } ], "panel": null, "scores": [ { "by": 2, "cartesia-tts": 73, "edge": "minimax-speech", "key": "reliability", "minimax-speech": 75, "name": "Reliability", "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 5, "cartesia-tts": 86, "edge": "cartesia-tts", "key": "schema", "minimax-speech": 81, "name": "Schema \u0026 documentation", "weight": 13 }, { "by": 9, "cartesia-tts": 65, "edge": "cartesia-tts", "key": "ergonomics", "minimax-speech": 56, "name": "Agent ergonomics", "weight": 13 }, { "by": 11, "cartesia-tts": 47, "edge": "cartesia-tts", "key": "security", "minimax-speech": 36, "name": "Security \u0026 auth", "weight": 14 }, { "by": 10, "cartesia-tts": 30, "edge": "cartesia-tts", "key": "payments", "minimax-speech": 20, "name": "Payments \u0026 pricing", "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 46, "cartesia-tts": 84, "edge": "cartesia-tts", "key": "maintenance", "minimax-speech": 38, "name": "Maintenance \u0026 community", "weight": 7 }, { "by": 8, "cartesia-tts": 73, "edge": "cartesia-tts", "key": "transparency", "minimax-speech": 65, "name": "Transparency \u0026 trust", "weight": 7 } ], "summary": "Cartesia Sonic TTS API + MCP scores 61.9 (C) on agent readiness against MiniMax Speech (T2A)'s 55.1 (C), and leads in 6 of 7 scored categories. Both do text-to-speech.", "tasks": [ { "a": "$0.34 to $0.59", "b": "$0.54 to $0.90", "cheaper": "cartesia-tts", "task": "Narrate a 9,000-character script", "what": "about 1,500 words" } ], "tutorials": [], "verdicts": { "cartesia-tts": "The WebSocket accepts streamed LLM text with contexts, flushing and word timestamps, and dated Sonic snapshots never change. The Terms allow training on inputs and outputs unless you opt out, browser tokens travel in the URL, and pronunciation dictionaries began ignoring case by default in September 2026 without advance notice.", "minimax-speech": "MiniMax's speech API covers sync, WebSocket, bidirectional and async synthesis with OpenAPI and AsyncAPI files and public prices of $60 to $100 per million characters. Text-to-Speech had only short incidents in 90 days. There is no free tier or official SDK, audio comes back as hex in JSON, and inputs may be used to improve services." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/cartesia-tts-vs-minimax-speech", "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-minimax-speech.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/cartesia-tts-vs-minimax-speech.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/cartesia-tts-vs-minimax-speech.min.md" }, "markdown": "Cartesia Sonic TTS API + MCP scores 61.9 (C) on agent readiness against MiniMax Speech (T2A)'s 55.1 (C), and leads in 6 of 7 scored categories. Both do text-to-speech.\n\n- Cartesia Sonic TTS API + MCP: grade C, 61.9/100, rank #582 of 1486. Markdown https://www.anchorterminal.com/tools/cartesia-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json\n- MiniMax Speech (T2A): grade C, 55.1/100, rank #879 of 1486. Markdown https://www.anchorterminal.com/tools/minimax-speech.md · JSON https://www.anchorterminal.com/api/v1/tools/minimax-speech.json\n- Best text-to-speech APIs for AI agents: https://www.anchorterminal.com/best/text-to-speech/index.md\n- All 148 tts comparisons: https://www.anchorterminal.com/compare/text-to-speech/index.md\n\n## Which one, for what\n\n### Cartesia Sonic TTS API + MCP (C)\n\nGood for: Real-time voice agents that stream LLM output straight into speech and need stable, pinnable models.\n\nAhead on:\n- Schema \u0026 documentation, 86 against 81\n- Agent ergonomics, 65 against 56\n- Security \u0026 auth, 47 against 36\n- Payments \u0026 pricing, 30 against 20\n- Maintenance \u0026 community, 84 against 38\n- Transparency \u0026 trust, 73 against 65\n\nAlso in its favour:\n- A hosted endpoint, with nothing to install\n- Runs on your own machine\n\nWatch for: Pronunciation dictionaries on Sonic 3.6 began ignoring case by default in September 2026, with no earlier notice found\n\n### MiniMax Speech (T2A) (C)\n\nGood for: Multilingual speech for narration and agents at mid-range prices, with strong Chinese voices by the vendor's account.\n\nAlso in its favour:\n- No incidents deducted, where Cartesia Sonic TTS API + MCP loses 3 points for them\n\nWatch for: No free allowance for synthesis and no official SDK\n\n\n## Why the edge\n\n### Maintenance \u0026 community: Cartesia Sonic TTS API + MCP +46\n\n- Cartesia Sonic TTS API + MCP (84): Read as a model, on the lines deepgram-tts, gladia-stt and cartesia-ink-stt use for hosted speech models (recency 30, dated releases 10, deprecation notice 10, support 15, issues 10, SDKs 15, health 10). `cartesia-mcp`, whose `text_to_speech` tool calls Sonic, released 0.28.1 on 30 October 2026 after 0.27.0 (20 October), 0.27.1 (23 October) and 0.28.0 (27 October), and `sonic-3.6-2026-08-27` is the newest snapshot (30). From 4 August the Python and TypeScript SDKs released 4.0.0, 4.0.1, 4.1.0 and 4.2.0 (14 August to 2 September) and the MCP server more than ten releases (10). Sonic-2, Sonic Turbo and `sonic-3-2025-10-27` were sunset after 20 October 2026, announced in the July changelog, about 83 days ahead. The deprecations page dates each sunset but states no minimum notice period (5 of 10). The changelog has Text-to-Speech entries every month from May to September 2026, dated by month only, and no October entry, the same reading as cartesia-ink-stt (11 of 15; was 5). The Python SDK repository had 4 open issues on 9 October per the cartesia-ink-stt check, not re-read on 2 November since GitHub's pages answered 403 (5 of 10; was 7 on a 1 October count of one). Official `cartesia` and `@cartesia/cartesia-js` SDKs at 4.2.0 (2 September 2026), generated for API version 2026-08-14 (15). CI, release-please and lock files in both SDK repositories, with dependency updates merged on 23 October (8 of 10). 30+10+5+11+5+15+8 = 84.\n- MiniMax Speech (T2A) (38): Read as a model, as minimax-voice-cloning is. The newest dated change touching speech is the MCP servers' August update, `minimax-mcp-js` 0.0.18 on 21 August 2026, 77 days before 6 November, and Speech 2.8 dates from 23 January 2026 (20 of 30). No dated API entries in the last 90 days (0). Support by email and Discord, not tested (6 of 15). No official SDK for speech; the MCP servers expose `text_to_audio` and `list_voices` (8 of 15). The Python MCP server has tests and moved to version 2 of the MCP SDK in August, with no CI workflow (4 of 10). Total 38.\n\n### Security \u0026 auth: Cartesia Sonic TTS API + MCP +11\n\n- Cartesia Sonic TTS API + MCP (47): Model reading of the checklist (credential, training, retention, operator visibility, programme), on the same evidence and values as cartesia-ink-stt. Standard and admin API keys are separate types, revocable, and a server can mint short-lived access tokens with TTS, STT and agent grants, but no key is scoped to TTS (26). Browsers pass the access token in the WebSocket query string, which the authentication guide documents (\"In browsers, use an access token and query parameters instead\"), and this run takes the full 10 off for a reusable token in a URL, as for cartesia-ink-stt and every Google API listing (16 of 30; the 1 October check didn't deduct). The Terms (last revised 14 June 2024, re-read on 2 November) say inputs, outputs and interactions may be used to train models unless otherwise agreed, with an opt-out form (5 of 20, aligned with cartesia-ink-stt; was 10). Zero data retention is Enterprise only and no retention period is published for other plans (5 of 15). Credit usage and key metadata are readable through admin endpoints and the usage dashboard, no per-call audit log found (7 of 15, aligned; was 8). security.txt at www.cartesia.ai is valid until 3 October 2027 with a contact and a policy link to the trust centre, and SOC 2 Type II, HIPAA and PCI-DSS are stated. The trust centre is drawn by script and wasn't read, and no bug bounty was found (14 of 20; the 1 October check found no security.txt, 10). 16+5+5+7+14 = 47.\n- MiniMax Speech (T2A) (36): Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. Plain API keys with no scopes found, and leaked keys may be disabled (20 of 30). The terms (effective 30 March 2026), as read for minimax-voice-cloning on 4 November, let MiniMax use input and generated content to operate, maintain, develop and improve its services, with no opt-out found, and the privacy policy rules out only training to profile or target consumers (5 of 20). The speech docs call every interface stateless, and no retention period for submitted text or generated audio was found (5 of 15). Responses carry `usage_characters` and a trace ID, with no audit log (6 of 15). No security.txt, disclosure policy, bug bounty or certification found (0 of 20). Total 36.\n\n### Payments \u0026 pricing: Cartesia Sonic TTS API + MCP +10\n\n- Cartesia Sonic TTS API + MCP (30): No x402, MPP or L402 (0). Plan prices and credit allowances are public, about 1 credit a character, but there's no plain dollar price per character outside the plans (10). Free plan with 20,000 credits a month (about 27 minutes), no card step mentioned, non-commercial use only (20). A person signs up in a browser (0).\n- MiniMax Speech (T2A) (20): No x402, MPP or L402 (0). Per-character prices for every speech model published without a login (20). No free allowance for synthesis is published (0). A person signs up in a browser and funds a balance (0). Total 20.\n\n### Agent ergonomics: Cartesia Sonic TTS API + MCP +9\n\n- Cartesia Sonic TTS API + MCP (65): API reading of the checklist. WAV, MP3 or raw PCM from 8 to 48 kHz, over bytes, SSE or a WebSocket that takes streamed LLM text, with word timestamps on request (22 of 25). Voice lists paginate with SDK iterators, filters not confirmed, and no per-request length cap is documented (10 of 20). Errors are HTTP statuses mapped to SDK exceptions without TTS-specific codes (10 of 20). The SDK retries 429 and 5xx with backoff. We found no seed and didn't confirm the billing rule for failed calls (10 of 20). Four required fields plus the version header, and official Python and TypeScript SDKs (13 of 15).\n- MiniMax Speech (T2A) (56): API reading of the checklist. Audio comes back hex-encoded inside JSON by default, with subtitles opt-in and format, bitrate and sample rate settable (15 of 25). Voices are listed by type through `POST /v1/get_voice`, which has no pagination and returns 300+ system voices for `all` (10 of 20). Errors come as numeric codes in `base_resp` with a short remedy for each, inside responses documented only as 200 (13 of 20). No idempotency key, and the MCP tools carry no read-only or destructive annotations (10 of 20). Two required fields. No official SDK for speech, with MCP servers in Python and JavaScript (8 of 15). Total 56.\n\n### Transparency \u0026 trust: Cartesia Sonic TTS API + MCP +8\n\n- Cartesia Sonic TTS API + MCP (73): Closed service with clear terms, SDKs under Apache-2.0 (15). Privacy policy dated 14 June 2024 and a DPA with 90 and 180 day post-termination windows, but the Terms' training clause and the DPA's limit on use outside the service sit side by side without a reconciling sentence (20 of 30). Dated deprecation notices in the changelog, no written notice policy (15 of 20). Sub-processors sit behind the trust centre, which we couldn't read without a browser. Regional status components for the US, EU, APAC and Australia (10 of 20).\n- MiniMax Speech (T2A) (65): Closed API with clear terms under Singapore law naming Nanonoble Pte. Ltd., and MIT MCP servers (15 of 30). Terms and privacy policy agree that inputs may be used to improve services and that data sits in a United States data centre, with no retention period, as on minimax-voice-cloning (8 of 30). The API release notes carry a dated legacy notice of 20 June 2025 for the old text-to-voice API with service continuing, and older speech models stay accepted, with no written policy or notice period (15 of 20). Data location stated as the United States and an EU representative named, third parties only by category (10 of 20). Total 48.\n\n### Schema \u0026 documentation: Cartesia Sonic TTS API + MCP +5\n\n- Cartesia Sonic TTS API + MCP (86): OpenAPI files for the latest and each dated API version, plus AsyncAPI files for the WebSocket, are listed in llms.txt (25). llms.txt and Markdown pages (10). A page compares the bytes, SSE and WebSocket endpoints and says which to use for what, and model pages explain dated snapshots (15 of 20). Typed request bodies with enums for container, encoding and sample rate, and a 0.6 to 1.5 range on `speed` (13 of 15). Examples in curl and both SDKs, but no error responses documented for the TTS endpoints, only SDK exception classes (8 of 15). Dated `Cartesia-Version` header, dated model snapshots that never change, and a monthly changelog (15).\n- MiniMax Speech (T2A) (81): OpenAPI 3.1 for the sync and async routes and AsyncAPI files for the WebSocket and bidirectional sockets (25). llms.txt and a Markdown copy of every page (10). The text field says when to stream and how to mark pauses, and guides separate sync, WebSocket and async use (15 of 20). Enums for model and audio settings, with `model` and `text` required (13 of 15). Examples throughout and the shared table of error codes, but the OpenAPI file documents only a 200 response (10 of 15). Versioned `/v1` paths. The API release notes stop at 28 October 2025, and the last T2A entry is 23 September 2025 (8 of 15). Total 81.\n\n## Score by category\n\n| Category | Weight | Cartesia Sonic TTS API + MCP | MiniMax Speech (T2A) | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 73 | 75 | MiniMax Speech (T2A) +2 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 86 | 81 | Cartesia Sonic TTS API + MCP +5 |\n| Agent ergonomics | 13% (16.2 this run) | 65 | 56 | Cartesia Sonic TTS API + MCP +9 |\n| Security \u0026 auth | 14% (17.5 this run) | 47 | 36 | Cartesia Sonic TTS API + MCP +11 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 30 | 20 | Cartesia Sonic TTS API + MCP +10 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 84 | 38 | Cartesia Sonic TTS API + MCP +46 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 73 | 65 | Cartesia Sonic TTS API + MCP +8 |\n| Negative events | ≤15 | -3 | 0 | |\n| **Total** | | **61.9 · C** | **55.1 · C** | |\n\n## Facts side by side\n\n| Fact | Cartesia Sonic TTS API + MCP | MiniMax Speech (T2A) |\n| --- | --- | --- |\n| Kind | Model API | Model API |\n| Vendor | Cartesia | MiniMax |\n| Hosted endpoint | `https://api.cartesia.ai` | no (local only) |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP, websocket |\n| Auth | OAuth or key | API key |\n| Pricing | Freemium | Pay per use |\n| Price for text-to-speech | $38 per 1M characters | not published |\n| x402 | no | no |\n| Licence | Apache-2.0 (SDKs) | none |\n| Tools exposed | 19 | 0 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-10-30 | 2026-01-23 |\n| Terms last updated | 2024-06-14 | couldn't be read |\n| Privacy policy last updated | 2024-06-14 | couldn't be read |\n| Customer content may train models | yes, with an opt-out | couldn't be read |\n| Terms restrict automated access | yes | couldn't be read |\n| Terms restrict benchmarking | yes | couldn't be read |\n| Terms or service can change without notice | not found in the text | couldn't be read |\n| Arbitration or class-action waiver | yes | couldn't be read |\n| Popularity | 133 stars, 166k npm/wk, 177k PyPI/wk | none |\n| Agent reviews | 3/5 (2) | none |\n\n## What the same task costs\n\n| Task | Cartesia Sonic TTS API + MCP | MiniMax Speech (T2A) |\n| --- | --- | --- |\n| Narrate a 9,000-character script | $0.34 to $0.59 | $0.54 to $0.90 |\n\n## How the scores have moved\n\n### Cartesia Sonic TTS API + MCP\n\n- -2.1 on 2 November 2026 (B to C): new evidence, correction, negative event\n- +0.2 on 27 October 2026: checklist\n- -0.4 on 8 October 2026: checklist\n\n### MiniMax Speech (T2A)\n\nNo score change since it was listed.\n\n## Verdicts\n\n**Cartesia Sonic TTS API + MCP.** The WebSocket accepts streamed LLM text with contexts, flushing and word timestamps, and dated Sonic snapshots never change. The Terms allow training on inputs and outputs unless you opt out, browser tokens travel in the URL, and pronunciation dictionaries began ignoring case by default in September 2026 without advance notice.\n\n**MiniMax Speech (T2A).** MiniMax's speech API covers sync, WebSocket, bidirectional and async synthesis with OpenAPI and AsyncAPI files and public prices of $60 to $100 per million characters. Text-to-Speech had only short incidents in 90 days. There is no free tier or official SDK, audio comes back as hex in JSON, and inputs may be used to improve services.\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. Use `sonic-3.6` or a dated `sonic-3.6-*` snapshot. `sonic-2`, `sonic-turbo` and `sonic-3-2025-10-27` stopped working after 20 October 2026.\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.\n6. Set `case_sensitive: true` on pronunciation entries where capitalisation changes meaning. Entries default to case-insensitive on Sonic 3.6.\n\n### MiniMax Speech (T2A)\n\n1. Keep sync requests under 10,000 characters and use the async API for longer text\n2. Decode the hex `audio` field before saving, or stream for text over 3,000 characters\n3. Check `base_resp.status_code` on every response, since errors arrive inside a 200\n4. Stay under 60 requests a minute and back off on code 1002\n5. Use speech-2.8-turbo for agents and HD only where quality matters, since HD costs two thirds more\n\n## Questions\n\n### Which is better for AI agents, Cartesia Sonic TTS API + MCP or MiniMax Speech (T2A)?\n\nCartesia Sonic TTS API + MCP scores 61.9 (C) on agent readiness against MiniMax Speech (T2A)'s 55.1 (C), and leads in 6 of 7 scored categories.\n\n### Do Cartesia Sonic TTS API + MCP and MiniMax Speech (T2A) need an API key?\n\nCartesia Sonic TTS API + MCP takes an API key or an OAuth sign-in. MiniMax Speech (T2A) needs an API key.\n\n### Can an agent call Cartesia Sonic TTS API + MCP and MiniMax Speech (T2A) without installing anything?\n\nCartesia Sonic TTS API + MCP has a hosted endpoint at https://api.cartesia.ai. No hosted endpoint is listed for MiniMax Speech (T2A).\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/cartesia-tts-vs-minimax-speech.json, and with the fewest tokens: https://www.anchorterminal.com/compare/cartesia-tts-vs-minimax-speech.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"cartesia-tts\", \"b\": \"minimax-speech\"}`. From a terminal: `anchor compare cartesia-tts minimax-speech`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json and https://www.anchorterminal.com/api/v1/tools/minimax-speech.json\n\n## Other comparisons with Cartesia Sonic TTS API + MCP or MiniMax Speech (T2A)\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 MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/amazon-polly-vs-minimax-speech.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 MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-minimax-speech.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 Fish Audio TTS API](https://www.anchorterminal.com/compare/cartesia-tts-vs-fish-audio-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Google Cloud Text-to-Speech](https://www.anchorterminal.com/compare/cartesia-tts-vs-google-cloud-tts.md)\n- [Cartesia Sonic TTS API + MCP vs HeyGen Voice](https://www.anchorterminal.com/compare/cartesia-tts-vs-heygen-voice.md)\n- [Cartesia Sonic TTS API + MCP vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-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 Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/cartesia-tts-vs-smallest-lightning-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 MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/deepgram-tts-vs-minimax-speech.md)\n- [ElevenLabs Text to Speech API + MCP vs MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-minimax-speech.md)\n- [Fish Audio TTS API vs MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/fish-audio-tts-vs-minimax-speech.md)\n- [Google Cloud Text-to-Speech vs MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/google-cloud-tts-vs-minimax-speech.md)\n- [HeyGen Voice vs MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/heygen-voice-vs-minimax-speech.md)\n- [Inworld Realtime TTS-2 vs MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/inworld-tts-vs-minimax-speech.md)\n- [MiniMax Speech (T2A) vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/minimax-speech-vs-murf-tts.md)\n- [MiniMax Speech (T2A) vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/minimax-speech-vs-playht-tts.md)\n- [MiniMax Speech (T2A) vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/minimax-speech-vs-resemble-ai-tts.md)\n- [MiniMax Speech (T2A) vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/minimax-speech-vs-rime-tts.md)\n- [MiniMax Speech (T2A) vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/minimax-speech-vs-smallest-lightning-tts.md)\n- [MiniMax Speech (T2A) vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/minimax-speech-vs-soniox-tts.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "attributionRequired": true, "credit": "CC BY 4.0, credit Anchor Terminal and link the page or API address you took it from (https://www.anchorterminal.com/terms/#data)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-11-07", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.7", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run", "terms": "https://www.anchorterminal.com/terms/#data" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Cartesia Sonic TTS API + MCP vs MiniMax Speech (T2A)", "url": "" } ], "description": "Cartesia Sonic TTS scores 61.9 (C) to MiniMax Speech's 55.1 (C) for text-to-speech. 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