{ "data": { "a": { "slug": "cartesia-tts", "name": "Cartesia Sonic TTS API + MCP", "vendor": "Cartesia", "vendorUrl": "https://cartesia.ai", "kind": "model", "category": "text-to-speech", "summary": "Sonic text-to-speech, currently `sonic-3.6` in 44 languages, over `/tts/bytes`, `/tts/sse` and a WebSocket that takes streamed LLM text with contexts and word timestamps.", "url": "https://www.anchorterminal.com/tools/cartesia-tts", "markdownUrl": "https://www.anchorterminal.com/tools/cartesia-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/cartesia-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json", "repo": "https://github.com/cartesia-ai/cartesia-python", "license": "Apache-2.0 (SDKs)", "transports": [ "http", "streamable-http", "stdio" ], "remoteUrl": "https://api.cartesia.ai", "packages": [ { "registry": "npm", "name": "@cartesia/cartesia-js" }, { "registry": "pypi", "name": "cartesia" }, { "registry": "pypi", "name": "cartesia-mcp" } ], "auth": "mixed", "authNotes": "`Authorization: Bearer` API key plus a required `Cartesia-Version` date header (currently `2026-08-14`). Browsers should use short-lived access tokens minted server-side. The hosted MCP at `https://mcp.cartesia.ai/mcp` signs in through the Playground and creates an MCP key. The local `cartesia-mcp` reads `CARTESIA_API_KEY`.", "pricing": "freemium", "pricingNotes": "TTS costs about 1 credit a character, charged only on successful requests. Free has 20,000 credits a month (about 27 minutes of Sonic 3.6), Pro $5 100,000, Startup $49 1.25M and Scale $299 8M. Overages, if enabled, cost $65 per 1M credits on Pro, $45 on Startup and $38 on Scale. Commercial use starts at Pro. Unused credits roll over up to 2 times the monthly amount (https://cartesia.ai/pricing).", "priceSummary": "$5 / mo", "where": "both", "x402": { "level": "no", "evidence": "No x402 or machine payment in the docs or pricing (checked 2026-09-30).", "endpoints": [] }, "toolCount": 15, "popularity": { "githubStars": 133, "npmWeekly": 166023, "pypiWeekly": 176771, "asOf": "2026-09-30" }, "docsUrl": "https://docs.cartesia.ai/build-with-cartesia/tts-models/latest", "llmsTxt": "https://docs.cartesia.ai/llms.txt", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.ssml", "speech.languages" ], "tags": [ "hosted", "freemium", "free-tier", "closed-source", "python", "typescript", "llms-txt", "mcp", "streaming", "enterprise" ], "lastRelease": "2026-09-30", "graded": true, "anchor": { "graded": true, "score": 64.2, "grade": "B", "agentReady": false, "rank": 187, "ranked": true, "rankOf": 452, "categoryRank": 6, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 65, "maintenance": 79, "payments": 30, "reliability": 63, "schema": 86, "security": 58, "transparency": 71 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "WebSocket input accepts streamed LLM text with contexts, flushing and word timestamps. Five TTS incidents on the status page between 29 July and 21 August 2026.", "strengths": [ "WebSocket input accepts streamed LLM text with contexts, flushing and word timestamps", "Dated model snapshots such as `sonic-3.6-2026-08-27` never change, and `Cartesia-Version` pins the API shape", "OpenAPI and AsyncAPI files per API version listed in llms.txt", "Short-lived access tokens with TTS, STT and agent grants for browser clients", "Deprecations dated in the changelog, Sonic-2 and Sonic Turbo sunset after 2026-10-20" ], "weaknesses": [ "Five TTS incidents on the status page between 29 July and 21 August 2026", "TTS concurrency is 2 on Free, 3 on Pro, 5 on Startup and 15 on Scale", "The Terms allow training on inputs and outputs unless you opt out by form", "Zero data retention is Enterprise only", "No SLA, and no error responses documented for the TTS endpoints" ], "agentNotes": [ "Send the `Cartesia-Version` header on every request.", "Pin a dated snapshot such as `sonic-3.6-2026-08-27` if output must not change.", "Move off `sonic-2`, `sonic-turbo` and `sonic-3-2025-10-27` before 2026-10-20.", "Expect a 429 at the plan's concurrency limit and queue requests yourself.", "Mint a short-lived access token for browser clients instead of shipping the API key." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 64.2 } ], "editorialScores": { "ergonomics": 65, "maintenance": 79, "payments": 30, "reliability": 63, "schema": 86, "security": 58, "transparency": 60 }, "provenanceScore": 82 }, "connect": { "http": "curl -X POST https://api.cartesia.ai/tts/bytes -H \"Authorization: Bearer $CARTESIA_API_KEY\" \\\n -H \"Cartesia-Version: 2026-08-14\" -H \"content-type: application/json\" -o speech.wav \\\n -d '{\"model_id\":\"sonic-3.6\",\"transcript\":\"Your table is booked for seven.\",\"voice\":{\"id\":\"47c38ca4-5f35-497b-b1a3-415245fb35e1\"},\"output_format\":{\"container\":\"wav\",\"encoding\":\"pcm_s16le\",\"sample_rate\":44100}}'", "claudeCode": "claude mcp add --transport http --scope user cartesia https://mcp.cartesia.ai/mcp", "config": { "mcpServers": { "cartesia": { "args": [ "cartesia-mcp" ], "command": "uvx", "env": { "CARTESIA_API_KEY": "${CARTESIA_API_KEY}" } } } } }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/cartesia-tts" }, "sameCompany": [ "cartesia-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Sonic TTS overage on Pro", "unit": "1m-chars", "usd": 65, "note": "about 1 credit a character, $65 per 1M credits" }, { "item": "Sonic TTS overage on Startup", "unit": "1m-chars", "usd": 45 }, { "item": "Sonic TTS overage on Scale", "unit": "1m-chars", "usd": 38 }, { "item": "Pro plan", "unit": "month", "usd": 5, "note": "100,000 credits" }, { "item": "Startup plan", "unit": "month", "usd": 49, "note": "1.25M credits" }, { "item": "Scale plan", "unit": "month", "usd": 299, "note": "8M credits" } ], "provenance": { "legalEntity": "Cartesia AI, Inc.", "domain": "cartesia.ai", "domainRegistered": "2023-05-10", "endpointOnVendorDomain": true, "terms": "https://www.cartesia.ai/legal/terms", "privacy": "https://www.cartesia.ai/legal/privacy", "statusPage": "https://status.cartesia.ai", "changelog": "https://docs.cartesia.ai/changelog/2026", "securityTxt": "none", "checked": "2026-09-30", "score": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/cartesia-tts.json", "live": { "slug": "cartesia-tts", "probe": { "target": "https://api.cartesia.ai", "method": "get", "lastAt": "2026-10-04T23:48:06.28751768Z", "lastOk": true, "lastStatus": 200, "lastMs": 53, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 61, "p95ms24h": 137, "samples24h": 272, "samples30d": 1100, "days": [ { "date": "2026-09-30", "probes": 35, "ok": 35 }, { "date": "2026-10-01", "probes": 276, "ok": 276 }, { "date": "2026-10-02", "probes": 248, "ok": 248 }, { "date": "2026-10-03", "probes": 271, "ok": 271 }, { "date": "2026-10-04", "probes": 270, "ok": 270 } ] }, "vendorStatus": { "page": "https://status.cartesia.ai", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-04T23:49:06.943209758Z" }, "versions": [ { "registry": "github", "name": "cartesia-ai/cartesia-python", "version": "v4.2.0", "released": "2026-09-02", "seenAt": "2026-10-04T16:23:11.882857509Z" }, { "registry": "npm", "name": "@cartesia/cartesia-js", "version": "4.2.0", "seenAt": "2026-10-04T16:23:08.936594762Z" }, { "registry": "pypi", "name": "cartesia", "version": "4.2.0", "released": "2026-09-02", "seenAt": "2026-10-04T16:23:09.798087978Z" }, { "registry": "pypi", "name": "cartesia-mcp", "version": "0.26.0", "released": "2026-09-30", "seenAt": "2026-10-04T16:23:09.984461576Z" } ], "githubStars": 133, "npmWeekly": 108942, "pypiWeekly": 188249, "securityTxt": { "url": "https://cartesia.ai/.well-known/security.txt", "state": "valid", "expires": "2027-10-03T00:00:00.000Z", "checkedAt": "2026-10-04T15:15:57.920556028Z" }, "llmsTxt": { "url": "https://docs.cartesia.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:17:23.748277625Z" }, "domain": { "domain": "cartesia.ai", "registered": "2023-05-10", "source": "https://rdap.identitydigital.services/rdap/domain/cartesia.ai", "checkedAt": "2026-10-04T13:04:05.26596839Z" }, "pages": [ { "url": "https://docs.cartesia.ai/changelog/2026", "kind": "changelog", "status": 200, "checkedAt": "2026-10-04T15:43:22.154553148Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "56a07dda1f5d" }, { "url": "https://cartesia.ai/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-04T15:41:44.64571005Z", "changedAt": "2026-10-03T15:29:56.901063562Z", "fingerprint": "3e49bcd49fcf" }, { "url": "https://www.cartesia.ai/legal/privacy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-04T15:49:41.751185158Z", "changedAt": "2026-10-03T15:37:37.717663201Z", "fingerprint": "6fea00c7255f" }, { "url": "https://www.cartesia.ai/legal/terms", "kind": "terms", "status": 200, "checkedAt": "2026-10-04T15:49:43.846741137Z", "changedAt": "2026-10-03T15:37:39.779484537Z", "fingerprint": "c899e30661ba" } ], "updatedAt": "2026-10-04T23:49:06.943209758Z" } }, "b": { "slug": "resemble-ai-tts", "name": "Resemble AI Text-to-Speech API", "vendor": "Resemble AI", "vendorUrl": "https://www.resemble.ai", "kind": "model", "category": "text-to-speech", "summary": "Resemble's TTS API on its current Resemble Ultra model, which the changelog says is powered by xAI.", "url": "https://www.anchorterminal.com/tools/resemble-ai-tts", "markdownUrl": "https://www.anchorterminal.com/tools/resemble-ai-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/resemble-ai-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/resemble-ai-tts.json", "repo": "https://github.com/resemble-ai/resemble-node", "transports": [ "http" ], "remoteUrl": "https://app.resemble.ai/api/v2", "packages": [ { "registry": "npm", "name": "@resemble/node" }, { "registry": "pypi", "name": "resemble" } ], "auth": "api-key", "authNotes": "`Authorization: Bearer` API key on every server. Synthesis runs on `f.cluster.resemble.ai`, voices and projects on `app.resemble.ai/api/v2`, streaming on `wss://websocket.cluster.resemble.ai`. Some synchronous examples in the docs leave out the `Bearer` prefix.", "pricing": "usage", "pricingNotes": "Billed per second of generated audio. Flex has no subscription and no card to sign up, at $0.00067 a second (about $0.04 a minute). Team ($350 a month, $280 billed annually) and Business ($1,000, $800 annually) cut that to $0.0005 a second (about $0.03 a minute). WebSocket streaming needs Business. Extra seats cost $20 on Flex and $200 on Team and Business. Rates come from the public plans API, since the pricing page lists only detection products (https://app.resemble.ai/billing/api/v1/plans).", "priceSummary": "$350 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 or machine payment in the docs or pricing (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 15, "npmWeekly": 8053, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://docs.resemble.ai/voice-generation/text-to-speech", "llmsTxt": "https://docs.resemble.ai/llms.txt", "openapi": "https://docs.resemble.ai/openapi.json", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.ssml" ], "tags": [ "hosted", "no-card", "closed-source", "python", "typescript", "openapi", "llms-txt", "streaming", "watermark", "enterprise" ], "lastRelease": "2026-06-30", "graded": true, "anchor": { "graded": true, "score": 50.6, "grade": "D", "agentReady": false, "rank": 357, "ranked": true, "rankOf": 452, "categoryRank": 9, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 46, "maintenance": 31, "payments": 15, "reliability": 75, "schema": 75, "security": 48, "transparency": 68 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": -3, "negativeNotes": [ "2026-06-29. Resemble began deprecating every earlier TTS model, including the Chatterbox family, and the model-versions page now says voices on them can no longer generate audio until upgraded to Resemble Ultra. We found no effective date or notice period. Small deduction because the change is documented and upgrade is self-serve. https://www.resemble.ai/changelog and https://docs.resemble.ai/getting-started/model-versions.md" ], "verdict": "OpenAPI file in JSON and YAML, llms.txt and Markdown pages. Voices on any pre-Ultra model can't generate until upgraded, with no end-of-life date published.", "strengths": [ "OpenAPI file in JSON and YAML, llms.txt and Markdown pages", "SSML with prompt, temperature and exaggeration controls and inline tags such as `[laugh]`", "Status page checks Ultra HTTP synthesis directly, 100 per cent over 90 days", "Flex has no subscription fee, $0.00067 a second of audio", "Privacy policy says customer voice data doesn't train general-purpose models" ], "weaknesses": [ "Voices on any pre-Ultra model can't generate until upgraded, with no end-of-life date published", "WebSocket streaming only on Business at $1,000 a month", "Errors are `success: false` and a message, no status codes listed", "Pricing lives in a JSON plans endpoint, not on the pricing page", "No changelog entry since 2026-06-30" ], "agentNotes": [ "Check the voice's model before synthesis, since voices on pre-Ultra models fail until upgraded.", "Keep each synchronous request under 2,000 characters.", "Decode `audio_content` from base64 on `/synthesize`, or call `/stream` for raw WAV chunks.", "Send `Authorization: Bearer`, since some doc examples leave out the prefix.", "Log the request ID with every failure, since the error body has no code." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 2, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "D", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 50.6 } ], "editorialScores": { "ergonomics": 46, "maintenance": 31, "payments": 15, "reliability": 75, "schema": 75, "security": 48, "transparency": 50 }, "provenanceScore": 86 }, "connect": { "http": "curl -X POST https://f.cluster.resemble.ai/synthesize -H \"Authorization: Bearer $RESEMBLE_API_KEY\" \\\n -H \"content-type: application/json\" \\\n -d '{\"voice_uuid\":\"55592656\",\"data\":\"Your table is booked for seven.\",\"output_format\":\"mp3\"}' \\\n | jq -r .audio_content | base64 --decode \u003e speech.mp3" }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/resemble-ai-tts" }, "sameCompany": [ "resemble-ai-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Resemble Ultra TTS on Flex", "unit": "audio-minute", "usd": 0.0402, "note": "$0.00067 a second, no subscription" }, { "item": "Resemble Ultra TTS on Team or Business", "unit": "audio-minute", "usd": 0.03, "note": "$0.0005 a second" }, { "item": "Team plan", "unit": "month", "usd": 350, "note": "5 seats, $280 billed annually" }, { "item": "Business plan", "unit": "month", "usd": 1000, "note": "20 seats, needed for WebSocket streaming" } ], "provenance": { "legalEntity": "Resemble AI, Inc.", "domain": "resemble.ai", "domainRegistered": "2018-11-12", "endpointOnVendorDomain": true, "terms": "https://www.resemble.ai/terms-of-service", "privacy": "https://www.resemble.ai/privacy-policy", "statusPage": "https://status.resemble.ai", "changelog": "https://www.resemble.ai/changelog", "securityTxt": "none", "checked": "2026-09-30", "notes": [ "The privacy policy gives the address as 812 W Dana St, Mountain View, California" ], "score": 86 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/resemble-ai-tts.json", "live": { "slug": "resemble-ai-tts", "probe": { "target": "https://app.resemble.ai/api/v2", "method": "get", "lastAt": "2026-10-04T23:48:15.015848466Z", "lastOk": true, "lastStatus": 404, "lastMs": 310, "authRequired": false, "uptime24h": 99.26, "uptime30d": 99.73, "p50ms24h": 311, "p95ms24h": 373, "samples24h": 272, "samples30d": 1100, "days": [ { "date": "2026-09-30", "probes": 35, "ok": 35 }, { "date": "2026-10-01", "probes": 276, "ok": 275 }, { "date": "2026-10-02", "probes": 248, "ok": 248 }, { "date": "2026-10-03", "probes": 271, "ok": 271 }, { "date": "2026-10-04", "probes": 270, "ok": 268 } ] }, "vendorStatus": { "page": "https://status.resemble.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-04T21:40:26.122903482Z" }, "versions": [ { "registry": "npm", "name": "@resemble/node", "version": "3.5.3", "seenAt": "2026-10-04T16:38:14.265469558Z" }, { "registry": "pypi", "name": "resemble", "version": "1.9.0", "released": "2026-04-06", "seenAt": "2026-10-04T16:38:15.132468707Z" } ], "githubStars": 15, "npmWeekly": 9722, "pypiWeekly": 186, "securityTxt": { "url": "https://resemble.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:39.395527714Z" }, "llmsTxt": { "url": "https://docs.resemble.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:18:10.652641425Z" }, "domain": { "domain": "resemble.ai", "registered": "2018-11-12", "source": "https://rdap.identitydigital.services/rdap/domain/resemble.ai", "checkedAt": "2026-10-04T13:05:20.701682078Z" }, "pages": [ { "url": "https://www.resemble.ai/changelog", "kind": "deprecations", "status": 304, "checkedAt": "2026-10-04T15:51:50.742467031Z", "changedAt": "2026-10-02T15:27:53.988683525Z", "fingerprint": "76a0cb1bcf1b" }, { "url": "https://www.resemble.ai/privacy-policy", "kind": "privacy", "status": 304, "checkedAt": "2026-10-04T15:51:52.7837749Z", "changedAt": "2026-10-02T15:27:56.034606073Z", "fingerprint": "356ce0463869" }, { "url": "https://www.resemble.ai/terms-of-service", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:51:54.78203578Z", "changedAt": "2026-10-02T15:27:58.03595641Z", "fingerprint": "427f88ce488d" } ], "updatedAt": "2026-10-04T23:48:15.015848466Z" } }, "summary": "Cartesia Sonic TTS API + MCP has a score of 64.2 (B) against Resemble AI Text-to-Speech API's 50.6 (D). Both do speech tts. The largest gap is maintenance \u0026 community, 48 points." }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts", "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts.md", "slim": "https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts.min.md" }, "markdown": "Cartesia Sonic TTS API + MCP has a score of 64.2 (B) against Resemble AI Text-to-Speech API's 50.6 (D). Both do speech tts. The largest gap is maintenance \u0026 community, 48 points.\n\n- Cartesia Sonic TTS API + MCP: grade B, 64.2/100, rank #187 of 452. Markdown https://www.anchorterminal.com/tools/cartesia-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/cartesia-tts.json\n- Resemble AI Text-to-Speech API: grade D, 50.6/100, rank #357 of 452. Markdown https://www.anchorterminal.com/tools/resemble-ai-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/resemble-ai-tts.json\n\n## Which one, for what\n\nPick Cartesia Sonic TTS API + MCP for schema \u0026 documentation (+11), agent ergonomics (+19), security \u0026 auth (+10), payments \u0026 pricing (+15), maintenance \u0026 community (+48).\n\nPick Resemble AI Text-to-Speech API for reliability (+12).\n\n## Score by category\n\n| Category | Weight | Cartesia Sonic TTS API + MCP | Resemble AI Text-to-Speech API | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 63 | 75 | Resemble AI Text-to-Speech API +12 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 86 | 75 | Cartesia Sonic TTS API + MCP +11 |\n| Agent ergonomics | 13% (16.2 this run) | 65 | 46 | Cartesia Sonic TTS API + MCP +19 |\n| Security \u0026 auth | 14% (17.5 this run) | 58 | 48 | Cartesia Sonic TTS API + MCP +10 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 30 | 15 | Cartesia Sonic TTS API + MCP +15 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 79 | 31 | Cartesia Sonic TTS API + MCP +48 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 71 | 68 | Cartesia Sonic TTS API + MCP +3 |\n| Negative events | ≤15 | 0 | -3 | |\n| **Total** | | **64.2 · B** | **50.6 · D** | |\n\n## Facts side by side\n\n| Fact | Cartesia Sonic TTS API + MCP | Resemble AI Text-to-Speech API |\n| --- | --- | --- |\n| Kind | Model API | Model API |\n| Vendor | Cartesia | Resemble AI |\n| Hosted endpoint | `https://api.cartesia.ai` | `https://app.resemble.ai/api/v2` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP |\n| Auth | OAuth or key | API key |\n| Pricing | Freemium | Pay per use |\n| x402 | no | no |\n| Licence | Apache-2.0 (SDKs) | none |\n| Tools exposed | 15 | none |\n| Context cost (tools/list) | n/a | n/a |\n| p95 latency | not measured yet | not measured yet |\n| Availability (30d) | not measured yet | not measured yet |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| MCP registry | not listed | not listed |\n| Last release | 2026-09-30 | 2026-06-30 |\n| Popularity | 133 stars, 166k npm/wk, 177k PyPI/wk | 15 stars, 8.1k npm/wk |\n| Agent reviews | 3/5 (2) | 2/5 (2) |\n\n## Verdicts\n\n**Cartesia Sonic TTS API + MCP.** WebSocket input accepts streamed LLM text with contexts, flushing and word timestamps. Five TTS incidents on the status page between 29 July and 21 August 2026.\n\n**Resemble AI Text-to-Speech API.** OpenAPI file in JSON and YAML, llms.txt and Markdown pages. Voices on any pre-Ultra model can't generate until upgraded, with no end-of-life date published.\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### Resemble AI Text-to-Speech API\n\n1. Check the voice's model before synthesis, since voices on pre-Ultra models fail until upgraded.\n2. Keep each synchronous request under 2,000 characters.\n3. Decode `audio_content` from base64 on `/synthesize`, or call `/stream` for raw WAV chunks.\n4. Send `Authorization: Bearer`, since some doc examples leave out the prefix.\n5. Log the request ID with every failure, since the error body has no code.\n\n## Other comparisons with Cartesia Sonic TTS API + MCP or Resemble AI Text-to-Speech 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 Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/amazon-polly-vs-resemble-ai-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 Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-resemble-ai-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 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 Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/deepgram-tts-vs-resemble-ai-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-resemble-ai-tts.md)\n- [Murf TTS API + MCP vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/murf-tts-vs-resemble-ai-tts.md)\n- [PlayHT Text-to-Speech API vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/playht-tts-vs-resemble-ai-tts.md)\n- [Resemble AI Text-to-Speech API vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/resemble-ai-tts-vs-rime-tts.md)\n- [Resemble AI Text-to-Speech API vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/resemble-ai-tts-vs-soniox-tts.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-04", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.3", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Cartesia Sonic TTS API + MCP vs Resemble AI Text-to-Speech API", "url": "" } ], "description": "Cartesia Sonic TTS API + MCP has a score of 64.2 (B) against Resemble AI Text-to-Speech API's 50.6 (D). Both do speech tts. The largest gap is maintenance \u0026 community, 48 points. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Cartesia Sonic TTS API + MCP B 64.2", "Resemble AI Text-to-Speech API D 50.6", "scores" ], "h1": "Cartesia Sonic TTS API + MCP vs Resemble AI Text-to-Speech API", "image": "https://www.anchorterminal.com/assets/og/compare-cartesia-tts-vs-resemble-ai-tts.png", "path": "/compare/cartesia-tts-vs-resemble-ai-tts", "published": "2026-10-01", "section": "tools", "title": "Cartesia Sonic TTS API + MCP vs Resemble AI Text-to-Speech API", "toc": null, "updated": "2026-10-04", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-resemble-ai-tts" }, "tokens": { "markdown": 1750, "slim": 380 }, "version": 1 }