{ "data": { "a": { "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", "dns": "resemble-ai-tts.grade.anchorterminal.com", "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 on the Flex, Team and Business plans, with WebSocket streaming on Business, per the 1 October 2026 check. Per-second and plan prices weren't re-read on 4 November 2026, and the earlier figures came from a billing data endpoint this run doesn't read.", "priceSummary": "Pay per use", "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": 48.5, "grade": "D", "agentReady": false, "rank": 1112, "ranked": true, "rankOf": 1486, "categoryRank": 15, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 46, "maintenance": 31, "payments": 0, "reliability": 75, "schema": 75, "security": 48, "transparency": 65 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-04" }, "negative": -3, "negativeNotes": [ "2026-06-29: the changelog says Resemble 'began deprecating all older voice models' that day, with no notice period, and the model versions page says voices on the seven end-of-life TTS models, the Chatterbox family among them, can no longer generate audio until upgraded to Resemble Ultra. Previously working requests fail with notice only after the change, so this run's same-day -3. Per the 1 October check, not re-read on 4 November. 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, and no per-second price could be confirmed from a public pricing page.", "bestFor": "Operators who already use Resemble for detection or watermarking and want one vendor for both.", "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 the 90 days to 1 October", "PerTh watermarking advertised on generated 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 the Business plan", "Errors are `success: false` and a message, no status codes listed", "The pricing page lists detection products, and no public page with synthesis prices was confirmed", "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": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 48.5 } ], "editorialScores": { "ergonomics": 46, "maintenance": 31, "payments": 0, "reliability": 75, "schema": 75, "security": 48, "transparency": 50 }, "provenanceScore": 80, "checked": { "categories": { "ergonomics": "2026-11-04", "maintenance": "2026-11-04", "payments": "2026-11-04", "reliability": "2026-11-04", "schema": "2026-11-04", "security": "2026-11-04", "transparency": "2026-11-04" }, "last": "2026-11-04", "lastMoved": "2026-11-04", "oldest": "2026-11-04", "stale": false, "staleAfterDays": 90 } }, "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", "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": 80 }, "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": "2026-11-07T18:20:50.991264768Z", "lastOk": true, "lastStatus": 404, "lastMs": 227, "authRequired": false, "uptime24h": 100, "uptime30d": 99.99, "p50ms24h": 173, "p95ms24h": 400, "samples24h": 239, "samples30d": 7910, "days": [ { "date": "2026-10-07", "probes": 272, "ok": 271 }, { "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": 250, "ok": 250 }, { "date": "2026-10-29", "probes": 249, "ok": 249 }, { "date": "2026-10-30", "probes": 249, "ok": 249 }, { "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.resemble.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-11-07T04:48:40.555681099Z" }, "versions": [ { "registry": "npm", "name": "@resemble/node", "version": "3.5.3", "seenAt": "2026-11-07T00:01:25.168575748Z" }, { "registry": "pypi", "name": "resemble", "version": "1.9.0", "released": "2026-04-06", "seenAt": "2026-11-07T00:01:26.046862921Z" } ], "githubStars": 15, "npmWeekly": 2708, "pypiWeekly": 266, "securityTxt": { "url": "https://resemble.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-11-07T16:01:21.226972005Z" }, "llmsTxt": { "url": "https://docs.resemble.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:33:47.179259411Z" }, "domain": { "domain": "resemble.ai", "registered": "2018-11-12", "source": "https://rdap.identitydigital.services/rdap/domain/resemble.ai", "checkedAt": "2026-11-01T14:11:31.603734411Z" }, "pages": [ { "url": "https://www.resemble.ai/changelog", "kind": "deprecations", "status": 200, "checkedAt": "2026-11-07T14:33:38.168034633Z", "changedAt": "2026-11-07T14:33:38.168034633Z", "fingerprint": "ac50b1bc491e" }, { "url": "https://www.resemble.ai/privacy-policy", "kind": "privacy", "status": 200, "checkedAt": "2026-11-07T14:33:40.356763964Z", "changedAt": "2026-11-07T14:33:40.356763964Z", "fingerprint": "3a28d9ab9d78" }, { "url": "https://www.resemble.ai/terms-of-service", "kind": "terms", "status": 200, "checkedAt": "2026-11-07T14:33:42.664278849Z", "changedAt": "2026-11-07T14:33:42.664278849Z", "fingerprint": "0d84418c4a04" } ], "github": { "repo": "resemble-ai/resemble-node", "checkedAt": "2026-11-02T09:21:24.993832128Z", "stars": 15, "archived": false, "issuesEnabled": true, "pushedAt": "2026-04-06T21:14:23Z", "openIssues": 3, "openPRs": 0, "issuesOpened90d": 0, "issuesClosed90d": 0, "prsMerged90d": 0, "replies": { "sampled": 4, "unanswered": 3, "medianDays": 50.5 } }, "updatedAt": "2026-11-07T18:20:50.991264768Z" } }, "answer": "Smallest.ai Lightning TTS scores 64.4 (B) on agent readiness against Resemble AI Text-to-Speech API's 48.5 (D), and leads in 6 of 7 scored categories. Resemble AI Text-to-Speech API leads on reliability.", "b": { "slug": "smallest-lightning-tts", "name": "Smallest.ai Lightning TTS", "vendor": "Smallest AI", "vendorUrl": "https://smallest.ai", "kind": "model", "category": "text-to-speech", "summary": "Smallest AI's Lightning text-to-speech API turns text into 44.1 kHz speech over HTTP, server-sent events or WebSocket, with the Lightning v3.1 and v3.1 Pro models in up to 31 languages, pronunciation dictionaries and word timestamps.", "url": "https://www.anchorterminal.com/tools/smallest-lightning-tts", "markdownUrl": "https://www.anchorterminal.com/tools/smallest-lightning-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/smallest-lightning-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/smallest-lightning-tts.json", "dns": "smallest-lightning-tts.grade.anchorterminal.com", "repo": "https://github.com/smallest-inc/smallest-python-sdk", "transports": [ "http", "websocket" ], "packages": [ { "registry": "pypi", "name": "smallestai" }, { "registry": "npm", "name": "smallestai" }, { "registry": "npm", "name": "@developer-smallestai/smallest-mcp-server" } ], "auth": "api-key", "authNotes": "Bearer `sk_` API key created in the dashboard after a browser signup, shared by every model and the Voice Agents API. Keys are shown once, revoked by deleting them and carry no scopes. Servers can mint `wat_` access tokens for browsers (30 to 900 seconds, inference routes only).", "pricing": "usage", "pricingNotes": "Pay as you go at $0.175 per 10,000 characters for Lightning v3.1 and $0.195 for Lightning v3.1 Pro. $10 in trial credits. Pay as you go is capped at 450M characters a month. Enterprise pricing, SLA and zero data retention by quote.", "priceSummary": "Pay per use", "where": "local", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs, OpenAPI file or pricing page (checked 2026-11-06). Credits are bought with a card on file.", "endpoints": [] }, "toolCount": 0, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-11-06" }, "docsUrl": "https://docs.smallest.ai/models/text-to-speech/overview", "llmsTxt": "https://docs.smallest.ai/llms.txt", "openapi": "https://docs.smallest.ai/openapi/models-api.json", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.languages" ], "tags": [ "hosted", "usage", "closed-source", "python", "typescript", "openapi", "llms-txt", "streaming", "mcp", "enterprise", "self-hosted" ], "lastRelease": "2026-11-02", "graded": true, "anchor": { "graded": true, "score": 64.4, "grade": "B", "agentReady": false, "rank": 469, "ranked": true, "rankOf": 1486, "categoryRank": 9, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 72, "maintenance": 68, "payments": 40, "reliability": 58, "schema": 92, "security": 52, "transparency": 70 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-06" }, "negative": 0, "verdict": "Lightning streams speech over HTTP, SSE or WebSocket with OpenAPI and AsyncAPI files and public prices of $0.175 to $0.195 per 10,000 characters. The default model retires on 30 November with 28 days' notice, published concurrency limits disagree, and the shared API failed in every region on five days in September.", "bestFor": "Low-latency speech for voice agents, with English, Hindi code-switching and Indic voices.", "strengths": [ "OpenAPI 3.1 and AsyncAPI 2.6 files cover the sync, SSE and WebSocket routes, with llms.txt and Markdown copies of every page", "Public prices of $0.175 per 10,000 characters for v3.1 and $0.195 for v3.1 Pro, with $10 of trial credits", "Pronunciation dictionaries, number and date reading controls, word timestamps and eight output formats", "A deprecations page with dates and migration steps, and dated preview checkpoints that run 30 days", "Region-pinned hosts in Mumbai and Oregon" ], "weaknesses": [ "`lightning_v3.1`, the default model, retires on 30 November 2026 after a 2 November notice, and clones made on it stop working", "Concurrency is published as 1, 10 and 15 on three different pages", "Health checks on the shared API failed in all three regions on 9, 10, 13, 14 and 15 September 2026, the longest about 64 minutes", "Keys grant full account access with no scopes, and the docs pass keys or tokens as URL query parameters on WebSockets", "No SSML, and zero data retention only on Enterprise or a $1,000 a month add-on" ], "agentNotes": [ "Always send `\"model\": \"lightning_v3.1_pro\"`, since requests with no model go to a model that retires on 30 November 2026", "Pick voices from `GET /waves/v1/lightning-v3.1-pro/get_voices`, because the v3.1 and v3.1 Pro catalogues differ", "Keep each request under 8,000 characters and split longer text", "Treat 429 as the concurrency ceiling and retry with backoff from 500 ms to 30 s, honouring Retry-After", "Fix names and acronyms with a pronunciation dictionary, since SSML isn't accepted" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 64.4 } ], "editorialScores": { "ergonomics": 72, "maintenance": 68, "payments": 40, "reliability": 58, "schema": 92, "security": 52, "transparency": 52 }, "provenanceScore": 87, "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": { "install": "pip install smallestai", "http": "curl -X POST \"https://api.smallest.ai/waves/v1/tts\" \\\n -H \"Authorization: Bearer $SMALLEST_API_KEY\" -H \"Content-Type: application/json\" -H \"Accept: audio/wav\" \\\n -d '{\"text\": \"Hello from Smallest AI.\", \"voice_id\": \"meher\", \"model\": \"lightning_v3.1_pro\", \"sample_rate\": 24000, \"output_format\": \"wav\"}' \\\n --output hello.wav", "claudeCode": "claude mcp add smallest -- npx -y @developer-smallestai/smallest-mcp-server" }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/smallest-lightning-tts" }, "sameCompany": [ "smallest-pulse-stt", "smallest-voice-clone" ], "area": "voice", "unitPrices": [ { "item": "Lightning v3.1", "unit": "1m-chars", "usd": 17.5, "note": "$0.175 per 10,000 characters, pay as you go; model retiring 30 November 2026" }, { "item": "Lightning v3.1 Pro", "unit": "1m-chars", "usd": 19.5, "note": "$0.195 per 10,000 characters, pay as you go" } ], "provenance": { "legalEntity": "Smallest, Inc.", "domain": "smallest.ai", "domainRegistered": "2023-09-02", "endpointOnVendorDomain": true, "terms": "https://smallest.ai/terms-of-service", "privacy": "https://smallest.ai/privacy-policy", "statusPage": "https://status.smallest.ai/", "changelog": "https://docs.smallest.ai/changelog/models", "securityTxt": "valid", "checked": "2026-11-06", "notes": [ "The terms of service (effective 21 October 2026) name Smallest Inc., 311 California Street, Suite 320, San Francisco, under California law. The privacy policy (effective 18 September 2026) names Smallest, Inc. with a registered office in Lewes, Delaware.", "The terms forbid accessing or searching the services with spiders, robots, crawlers or similar data mining tools except through means Smallest makes available. Only public pages were read, with no account.", "smallest.ai/robots.txt allows all crawlers including ClaudeBot, with Content-Signal ai-train=yes, search=yes, ai-input=yes. docs.smallest.ai/robots.txt allows all paths except /api/fern-docs/.", "/.well-known/security.txt names security@smallest.ai and expires 31 December 2026. /security.txt returns 404.", "RDAP gives smallest.ai a registration date of 2 September 2023.", "Every docs page served as Markdown opens with a block addressed to AI assistants that says which models to prefer. It was read as data, not followed.", "firstReleased is left empty. No dated launch of the Models API was found on a page our reader may fetch." ], "score": 87 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/smallest-lightning-tts.json", "live": { "slug": "smallest-lightning-tts", "vendorStatus": { "page": "https://status.smallest.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-11-07T04:48:45.761951958Z" }, "versions": [ { "registry": "github", "name": "smallest-inc/smallest-python-sdk", "version": "v2.1.0", "released": "2025-03-04", "seenAt": "2026-11-07T00:06:35.435989203Z" }, { "registry": "npm", "name": "@developer-smallestai/smallest-mcp-server", "version": "0.11.2", "seenAt": "2026-11-07T00:06:33.7720962Z" }, { "registry": "npm", "name": "smallestai", "version": "1.0.1", "seenAt": "2026-11-07T00:06:32.999034745Z" }, { "registry": "pypi", "name": "smallestai", "version": "5.14.0", "released": "2026-10-07", "seenAt": "2026-11-07T00:06:32.730014258Z" } ], "githubStars": 42, "npmWeekly": 149, "pypiWeekly": 850, "securityTxt": { "url": "https://smallest.ai/.well-known/security.txt", "state": "valid", "expires": "2026-12-31T23:59:59.000Z", "checkedAt": "2026-11-07T16:01:21.76871346Z" }, "llmsTxt": { "url": "https://docs.smallest.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:33:56.775686182Z" }, "pages": [ { "url": "https://docs.smallest.ai/changelog/models", "kind": "changelog", "status": 200, "checkedAt": "2026-11-07T14:08:02.477867618Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "5541546461b9" }, { "url": "https://smallest.ai/privacy-policy", "kind": "privacy", "status": 200, "checkedAt": "2026-11-07T14:20:10.527086718Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "2296cee567f0" }, { "url": "https://smallest.ai/terms-of-service", "kind": "terms", "status": 200, "checkedAt": "2026-11-07T14:20:12.776174427Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "27186e5f758e" } ], "updatedAt": "2026-11-07T16:01:21.76871346Z" } }, "edges": [ { "by": 40, "category": "payments", "leads": "smallest-lightning-tts", "name": "Payments \u0026 pricing", "reasons": { "a": "No x402, MPP or L402 (0). The per-second prices ($0.00067 on Flex, $0.0005 on Team and Business) were read on 30 September from app.resemble.ai/billing/api/v1/plans, a billing data endpoint this run doesn't read, so that reading is struck, and the pricing pages can't be re-read under the terms, so no per-unit price stands today (0). No free synthesis allowance per the 1 October check (0). A person signs up in a browser (0).", "b": "No x402, MPP or L402 (0). Per-character prices for both models published without a login (20). Pay as you go starts with $10 of trial credits, which the terms also describe, and no page says a card is needed to claim them, read as inworld-tts's free plan was (20). A person signs up in a browser at app.smallest.ai and creates the key in the dashboard, and top-ups go to a card on file (0). Total 40." }, "scores": { "a": 0, "b": 40 } }, { "by": 37, "category": "maintenance", "leads": "smallest-lightning-tts", "name": "Maintenance \u0026 community", "reasons": { "a": "Read as a model. The newest changelog entry is 2026-06-30 per the 1 October check, not re-read on 4 November (terms), 127 days old (10). No dated entries in the last 90 days that we could read (0 of 10). Older models were deprecated on 2026-06-29 and the docs say voices on them can't generate until upgraded, with no effective date published (0 of 10). Public changelog and a support address, SDK issue trackers not checked (8 of 25). The Node SDK clone on 4 November still ends at 754a91e (6 April 2026, 3.5.3); Python 1.9.0 of 6 April per the 1 October check, not re-read. Neither has a release since the June model changes (10 of 15). The Python SDK still declares support from Python 3.6, and the Node repository has no CI workflow and no release tags (3 of 10).", "b": "Read as a model. The newest Lightning changelog entry is dated 2 November 2026 (the v3.1 retirement notice), after a preview checkpoint on 29 October (30). Dated Lightning entries on 10, 23 and 28 August, 29 September, 14, 17 and 29 October and 2 November count, less 5 for churn, because the default model retires 28 days after its notice and clones made on it stop working (15 of 20). Public changelog, email support and a Discord server, with no evidence read of how they answer (10 of 15). The Python SDK `smallestai` 5.14.0 dates from 7 October, but the npm Node SDK has not been published since May 2025 (8 of 15). The Python SDK repository runs CI and release workflows, but has no licence file (5 of 10). Total 68." }, "scores": { "a": 31, "b": 68 } }, { "by": 26, "category": "ergonomics", "leads": "smallest-lightning-tts", "name": "Agent ergonomics", "reasons": { "a": "API reading of the checklist. WAV or MP3 from 8 to 48 kHz at 16, 24 or 32-bit, but synchronous synthesis returns the whole clip as base64 inside JSON (18 of 25). 2,000 characters per synchronous or HTTP stream request, 3,000 per WebSocket message. Longer scripts go through projects and clips (10 of 20). Errors are a boolean and a message, with advice to log the request ID (5 of 20). No retry, idempotency or billing-on-failure guidance found (0 of 20). Two required fields, a voice UUID and the text, and SDKs in Node and Python (13 of 15). The Node SDK is unchanged since 6 April 2026 (clone, 4 November); the rest per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means).", "b": "API reading of the checklist. Eight output formats, a choice of sample rate and word timestamps only when asked (22 of 25). Voices are listed per model and the docs say they filter by language and accent. Paging wasn't confirmed (14 of 20). Errors carry `error` and `message` fields with a shared status-code guide, without TTS-specific codes (14 of 20). Synthesis is stateless and `request_id` is echoed for correlation, but there is no idempotency key and billing of a retried request isn't stated (10 of 20). Two required fields, `text` and `voice_id`, but the default model retires on 30 November. Official Python and Node SDKs, with the Node SDK last published in May 2025 (12 of 15). Total 72." }, "scores": { "a": 46, "b": 72 } }, { "by": 17, "category": "reliability", "leads": "resemble-ai-tts", "name": "Reliability", "reasons": { "a": "Checkly status page with a Resemble Ultra HTTP check under Text-To-Speech and an activity history (20). One TTS event in the last 90 days, a 1-minute check failure on 22 September, and 100 per cent uptime on that check over 90 days. The page monitors HTTP synthesis only, not the WebSocket (30). 40 requests a second per token published, with WebSocket connection limits in the docs (15). No 429 behaviour or retry guidance found (0). No SLA found (0). Resemble Ultra is the current GA model (10). All per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means). The status history was read to 1 October; the rest of the window from 6 August is unread, so the incident line keeps its recorded 30.", "b": "BetterStack status page at status.smallest.ai with components for the Global, India and USA APIs (one health check covers the Agents and Models APIs), docs, the app and Electron, and per-component history (20). In the 90 days from 8 August the health checks on the shared API failed in all three regions on 9, 10, 13, 14 and 15 September (about 8, 21, 33, 17 and 64 minutes of flapping), in the Global and India regions on 11 and 17 September (12 minutes each), and in the USA region alone on 1, 3, 5, 12, 21 and 30 September (6 to 62 minutes) and 6 October (12 minutes). Outages in every region at once are read as wide errors, so several majors (0). Limits are published with numbers but disagree. The limits page says one TTS request at a time per account with up to five sockets, the Lightning v3.1 Pro card says 10 concurrent and the pricing page says 15 streams and 100 requests a minute on pay as you go (8 of 15). 429 is documented with exponential backoff from 500 ms to 30 s and Retry-After when present, and the limits page tells clients to expect 429s at the concurrency ceiling (15). An infrastructure SLA of 99.99 per cent is named for Enterprise only, with no terms, and the terms disclaim any availability commitment (5 of 10). `lightning_v3.1_pro` is stable and only the dated checkpoint is preview (10). 20 + 0 + 8 + 15 + 5 + 10 = 58." }, "scores": { "a": 75, "b": 58 } }, { "by": 17, "category": "schema", "leads": "smallest-lightning-tts", "name": "Schema \u0026 documentation", "reasons": { "a": "OpenAPI file in JSON and YAML at docs.resemble.ai (25). llms.txt with Markdown pages (10). The docs separate synchronous, HTTP streaming and WebSocket synthesis and say WebSocket needs Business, but rarely say when not to use one (12 of 20). Request bodies typed in the spec. The model is chosen by the voice, not the request (12 of 15). Examples on each endpoint, but the errors page only describes `success: false` with a `message` and lists no status codes (6 of 15). `/api/v2` paths and a dated product changelog shared with detection (10 of 15). All per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means).", "b": "OpenAPI 3.1 for the sync and SSE routes and AsyncAPI 2.6 for the WebSocket, with request and event schemas (25). llms.txt and a Markdown copy of every page (10). A transport guide, model cards and the compare page say which model and transport suit which job, but changelog entries correct the language lists and enums the docs and spec carried (15 of 20). Typed fields with enums for model, sample rate, language and output format, an 8,000-character limit and pattern rules on `session_id` and `request_id` (14 of 15). Examples in curl, Python and JavaScript, with error bodies on the reference and a shared error page (13 of 15). Versioned `/v1` paths, a dated Lightning changelog and dated preview checkpoints (15). Total 92." }, "scores": { "a": 75, "b": 92 } }, { "by": 5, "category": "transparency", "leads": "smallest-lightning-tts", "name": "Transparency \u0026 trust", "reasons": { "a": "Closed service with clear terms (15 of 30). The privacy policy gives retention periods and links a sub-processor list, but names Google Cloud, Render and Cerebrium as infrastructure while the changelog calls Resemble Ultra xAI-powered, and no xAI processing is mentioned (15 of 30). Deprecation started on a dated changelog entry (29 June 2026), with no end-of-life date or policy (5 of 20). The voice cloning listing gives 10 for the same entry and its model versions page reading. That split is left for a re-read. US hosting with named regions and UK processing for Enterprise on request, sub-processor list at trust.resemble.ai (15 of 20). All per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means); the terms of 14 August 2026 were re-read on 4 November.", "b": "Closed service with clear terms naming Smallest Inc. under California law (15). The ZDR page is specific about what each mode keeps, but the terms' no-training clause and the privacy policy's machine-learning use of usage data sit side by side, the privacy policy gives no retention periods, and the policy doesn't mention the DPA a footer link points to (15 of 30). A deprecations page gives statuses, dates and migration steps, and earlier models answer 410 with a pointer. The notice for the default `lightning_v3.1`, dated 2 November, gives 28 days before voices change and v3.1 clones stop working, and the terms let Smallest discontinue services without notice (12 of 20). Two regions named (Mumbai and Oregon) with region-pinned hosts, and only Google Analytics and Fullstory named among third parties, with no sub-processor list found (10 of 20). Total 52." }, "scores": { "a": 65, "b": 70 } } ], "facts": [ { "a": "Model API", "b": "Model API", "name": "Kind" }, { "a": "Resemble AI", "b": "Smallest AI", "name": "Vendor" }, { "a": "https://app.resemble.ai/api/v2", "b": "no (local only)", "name": "Hosted endpoint" }, { "a": "HTTP", "b": "HTTP, websocket", "name": "Transports" }, { "a": "API key", "b": "API key", "name": "Auth" }, { "a": "Pay per use", "b": "Pay per use", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "none", "b": "0", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-06-30", "b": "2026-11-02", "name": "Last release" }, { "a": "2026-08-14", "b": "no date given", "name": "Terms last updated" }, { "a": "2026-08-14", "b": "no date given", "name": "Privacy policy last updated" }, { "a": "not found in the text", "b": "not found in the text", "name": "Customer content may train models" }, { "a": "yes", "b": "not found in the text", "name": "Terms restrict automated access" }, { "a": "yes", "b": "not found in the text", "name": "Terms restrict benchmarking" }, { "a": "yes", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "yes", "b": "yes", "name": "Arbitration or class-action waiver" }, { "a": "15 stars, 8.1k npm/wk", "b": "none", "name": "Popularity" }, { "a": "2/5 (2)", "b": "none", "name": "Agent reviews" } ], "faq": [ { "answer": "Smallest.ai Lightning TTS scores 64.4 (B) on agent readiness against Resemble AI Text-to-Speech API's 48.5 (D), and leads in 6 of 7 scored categories. Resemble AI Text-to-Speech API leads on reliability.", "question": "Which is better for AI agents, Resemble AI Text-to-Speech API or Smallest.ai Lightning TTS?" }, { "answer": "Both need an API key.", "question": "Do Resemble AI Text-to-Speech API and Smallest.ai Lightning TTS need an API key?" }, { "answer": "Resemble AI Text-to-Speech API has a hosted endpoint at https://app.resemble.ai/api/v2. No hosted endpoint is listed for Smallest.ai Lightning TTS.", "question": "Can an agent call Resemble AI Text-to-Speech API and Smallest.ai Lightning TTS without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 75 against 58" ], "also": [ "A hosted endpoint, with nothing to install", "Free to start without a card" ], "goodFor": "Operators who already use Resemble for detection or watermarking and want one vendor for both.", "slug": "resemble-ai-tts", "watchFor": "Voices on any pre-Ultra model can't generate until upgraded, with no end-of-life date published" }, { "aheadOn": [ "Schema \u0026 documentation, 92 against 75", "Agent ergonomics, 72 against 46", "Payments \u0026 pricing, 40 against 0", "Maintenance \u0026 community, 68 against 31", "Transparency \u0026 trust, 70 against 65" ], "also": [ "No incidents deducted, where Resemble AI Text-to-Speech API loses 3 points for them" ], "goodFor": "Low-latency speech for voice agents, with English, Hindi code-switching and Indic voices.", "slug": "smallest-lightning-tts", "watchFor": "`lightning_v3.1`, the default model, retires on 30 November 2026 after a 2 November notice, and clones made on it stop working" } ], "history": { "resemble-ai-tts": [ { "causes": [ "correction" ], "date": "2026-11-04", "delta": -1.8, "from": 50.3, "fromGrade": "D", "to": 48.5, "toGrade": "D" }, { "causes": [ "evidence" ], "date": "2026-10-29", "delta": -0.1, "from": 50.4, "fromGrade": "D", "to": 50.3, "toGrade": "D" }, { "causes": [ "method" ], "date": "2026-10-27", "delta": 0.1, "from": 50.3, "fromGrade": "D", "to": 50.4, "toGrade": "D" } ], "smallest-lightning-tts": null }, "job": { "capability": "speech.tts", "name": "Text-to-speech" }, "others": [ { "json": "https://www.anchorterminal.com/compare/amazon-polly-vs-resemble-ai-tts.json", "title": "Amazon Polly vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/amazon-polly-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/amazon-polly-vs-smallest-lightning-tts.json", "title": "Amazon Polly vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/amazon-polly-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-resemble-ai-tts.json", "title": "Azure AI Speech text-to-speech vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-smallest-lightning-tts.json", "title": "Azure AI Speech text-to-speech vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-smallest-lightning-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-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/deepgram-tts-vs-resemble-ai-tts.json", "title": "Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/deepgram-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/deepgram-tts-vs-smallest-lightning-tts.json", "title": "Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/deepgram-tts-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-resemble-ai-tts.json", "title": "ElevenLabs Text to Speech API + MCP vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-smallest-lightning-tts.json", "title": "ElevenLabs Text to Speech API + MCP vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-resemble-ai-tts.json", "title": "Fish Audio TTS API vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-smallest-lightning-tts.json", "title": "Fish Audio TTS API vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/google-cloud-tts-vs-resemble-ai-tts.json", "title": "Google Cloud Text-to-Speech vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/google-cloud-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/google-cloud-tts-vs-smallest-lightning-tts.json", "title": "Google Cloud Text-to-Speech vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/google-cloud-tts-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/heygen-voice-vs-resemble-ai-tts.json", "title": "HeyGen Voice vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/heygen-voice-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/heygen-voice-vs-smallest-lightning-tts.json", "title": "HeyGen Voice vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/heygen-voice-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-resemble-ai-tts.json", "title": "Inworld Realtime TTS-2 vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-smallest-lightning-tts.json", "title": "Inworld Realtime TTS-2 vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-smallest-lightning-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-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/murf-tts-vs-resemble-ai-tts.json", "title": "Murf TTS API + MCP vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/murf-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/murf-tts-vs-smallest-lightning-tts.json", "title": "Murf TTS API + MCP vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/murf-tts-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/playht-tts-vs-resemble-ai-tts.json", "title": "PlayHT Text-to-Speech API vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/playht-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/playht-tts-vs-smallest-lightning-tts.json", "title": "PlayHT Text-to-Speech API vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/playht-tts-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-rime-tts.json", "title": "Resemble AI Text-to-Speech API vs Rime TTS API + MCP", "url": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-rime-tts" }, { "json": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-soniox-tts.json", "title": "Resemble AI Text-to-Speech API vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/rime-tts-vs-smallest-lightning-tts.json", "title": "Rime TTS API + MCP vs Smallest.ai Lightning TTS", "url": "https://www.anchorterminal.com/compare/rime-tts-vs-smallest-lightning-tts" }, { "json": "https://www.anchorterminal.com/compare/smallest-lightning-tts-vs-soniox-tts.json", "title": "Smallest.ai Lightning TTS vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/smallest-lightning-tts-vs-soniox-tts" } ], "panel": null, "scores": [ { "by": 17, "edge": "resemble-ai-tts", "key": "reliability", "name": "Reliability", "resemble-ai-tts": 75, "smallest-lightning-tts": 58, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 17, "edge": "smallest-lightning-tts", "key": "schema", "name": "Schema \u0026 documentation", "resemble-ai-tts": 75, "smallest-lightning-tts": 92, "weight": 13 }, { "by": 26, "edge": "smallest-lightning-tts", "key": "ergonomics", "name": "Agent ergonomics", "resemble-ai-tts": 46, "smallest-lightning-tts": 72, "weight": 13 }, { "by": 4, "edge": "smallest-lightning-tts", "key": "security", "name": "Security \u0026 auth", "resemble-ai-tts": 48, "smallest-lightning-tts": 52, "weight": 14 }, { "by": 40, "edge": "smallest-lightning-tts", "key": "payments", "name": "Payments \u0026 pricing", "resemble-ai-tts": 0, "smallest-lightning-tts": 40, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 37, "edge": "smallest-lightning-tts", "key": "maintenance", "name": "Maintenance \u0026 community", "resemble-ai-tts": 31, "smallest-lightning-tts": 68, "weight": 7 }, { "by": 5, "edge": "smallest-lightning-tts", "key": "transparency", "name": "Transparency \u0026 trust", "resemble-ai-tts": 65, "smallest-lightning-tts": 70, "weight": 7 } ], "summary": "Smallest.ai Lightning TTS scores 64.4 (B) on agent readiness against Resemble AI Text-to-Speech API's 48.5 (D), and leads in 6 of 7 scored categories. Resemble AI Text-to-Speech API leads on reliability. Both do text-to-speech.", "tasks": null, "tutorials": [], "verdicts": { "resemble-ai-tts": "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, and no per-second price could be confirmed from a public pricing page.", "smallest-lightning-tts": "Lightning streams speech over HTTP, SSE or WebSocket with OpenAPI and AsyncAPI files and public prices of $0.175 to $0.195 per 10,000 characters. The default model retires on 30 November with 28 days' notice, published concurrency limits disagree, and the shared API failed in every region on five days in September." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-smallest-lightning-tts", "json": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-smallest-lightning-tts.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-smallest-lightning-tts.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-smallest-lightning-tts.min.md" }, "markdown": "Smallest.ai Lightning TTS scores 64.4 (B) on agent readiness against Resemble AI Text-to-Speech API's 48.5 (D), and leads in 6 of 7 scored categories. Resemble AI Text-to-Speech API leads on reliability. Both do text-to-speech.\n\n- Resemble AI Text-to-Speech API: grade D, 48.5/100, rank #1112 of 1486. Markdown https://www.anchorterminal.com/tools/resemble-ai-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/resemble-ai-tts.json\n- Smallest.ai Lightning TTS: grade B, 64.4/100, rank #469 of 1486. Markdown https://www.anchorterminal.com/tools/smallest-lightning-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/smallest-lightning-tts.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### Resemble AI Text-to-Speech API (D)\n\nGood for: Operators who already use Resemble for detection or watermarking and want one vendor for both.\n\nAhead on:\n- Reliability, 75 against 58\n\nAlso in its favour:\n- A hosted endpoint, with nothing to install\n- Free to start without a card\n\nWatch for: Voices on any pre-Ultra model can't generate until upgraded, with no end-of-life date published\n\n### Smallest.ai Lightning TTS (B)\n\nGood for: Low-latency speech for voice agents, with English, Hindi code-switching and Indic voices.\n\nAhead on:\n- Schema \u0026 documentation, 92 against 75\n- Agent ergonomics, 72 against 46\n- Payments \u0026 pricing, 40 against 0\n- Maintenance \u0026 community, 68 against 31\n- Transparency \u0026 trust, 70 against 65\n\nAlso in its favour:\n- No incidents deducted, where Resemble AI Text-to-Speech API loses 3 points for them\n\nWatch for: `lightning_v3.1`, the default model, retires on 30 November 2026 after a 2 November notice, and clones made on it stop working\n\n\n## Why the edge\n\n### Payments \u0026 pricing: Smallest.ai Lightning TTS +40\n\n- Resemble AI Text-to-Speech API (0): No x402, MPP or L402 (0). The per-second prices ($0.00067 on Flex, $0.0005 on Team and Business) were read on 30 September from app.resemble.ai/billing/api/v1/plans, a billing data endpoint this run doesn't read, so that reading is struck, and the pricing pages can't be re-read under the terms, so no per-unit price stands today (0). No free synthesis allowance per the 1 October check (0). A person signs up in a browser (0).\n- Smallest.ai Lightning TTS (40): No x402, MPP or L402 (0). Per-character prices for both models published without a login (20). Pay as you go starts with $10 of trial credits, which the terms also describe, and no page says a card is needed to claim them, read as inworld-tts's free plan was (20). A person signs up in a browser at app.smallest.ai and creates the key in the dashboard, and top-ups go to a card on file (0). Total 40.\n\n### Maintenance \u0026 community: Smallest.ai Lightning TTS +37\n\n- Resemble AI Text-to-Speech API (31): Read as a model. The newest changelog entry is 2026-06-30 per the 1 October check, not re-read on 4 November (terms), 127 days old (10). No dated entries in the last 90 days that we could read (0 of 10). Older models were deprecated on 2026-06-29 and the docs say voices on them can't generate until upgraded, with no effective date published (0 of 10). Public changelog and a support address, SDK issue trackers not checked (8 of 25). The Node SDK clone on 4 November still ends at 754a91e (6 April 2026, 3.5.3); Python 1.9.0 of 6 April per the 1 October check, not re-read. Neither has a release since the June model changes (10 of 15). The Python SDK still declares support from Python 3.6, and the Node repository has no CI workflow and no release tags (3 of 10).\n- Smallest.ai Lightning TTS (68): Read as a model. The newest Lightning changelog entry is dated 2 November 2026 (the v3.1 retirement notice), after a preview checkpoint on 29 October (30). Dated Lightning entries on 10, 23 and 28 August, 29 September, 14, 17 and 29 October and 2 November count, less 5 for churn, because the default model retires 28 days after its notice and clones made on it stop working (15 of 20). Public changelog, email support and a Discord server, with no evidence read of how they answer (10 of 15). The Python SDK `smallestai` 5.14.0 dates from 7 October, but the npm Node SDK has not been published since May 2025 (8 of 15). The Python SDK repository runs CI and release workflows, but has no licence file (5 of 10). Total 68.\n\n### Agent ergonomics: Smallest.ai Lightning TTS +26\n\n- Resemble AI Text-to-Speech API (46): API reading of the checklist. WAV or MP3 from 8 to 48 kHz at 16, 24 or 32-bit, but synchronous synthesis returns the whole clip as base64 inside JSON (18 of 25). 2,000 characters per synchronous or HTTP stream request, 3,000 per WebSocket message. Longer scripts go through projects and clips (10 of 20). Errors are a boolean and a message, with advice to log the request ID (5 of 20). No retry, idempotency or billing-on-failure guidance found (0 of 20). Two required fields, a voice UUID and the text, and SDKs in Node and Python (13 of 15). The Node SDK is unchanged since 6 April 2026 (clone, 4 November); the rest per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means).\n- Smallest.ai Lightning TTS (72): API reading of the checklist. Eight output formats, a choice of sample rate and word timestamps only when asked (22 of 25). Voices are listed per model and the docs say they filter by language and accent. Paging wasn't confirmed (14 of 20). Errors carry `error` and `message` fields with a shared status-code guide, without TTS-specific codes (14 of 20). Synthesis is stateless and `request_id` is echoed for correlation, but there is no idempotency key and billing of a retried request isn't stated (10 of 20). Two required fields, `text` and `voice_id`, but the default model retires on 30 November. Official Python and Node SDKs, with the Node SDK last published in May 2025 (12 of 15). Total 72.\n\n### Reliability: Resemble AI Text-to-Speech API +17\n\n- Resemble AI Text-to-Speech API (75): Checkly status page with a Resemble Ultra HTTP check under Text-To-Speech and an activity history (20). One TTS event in the last 90 days, a 1-minute check failure on 22 September, and 100 per cent uptime on that check over 90 days. The page monitors HTTP synthesis only, not the WebSocket (30). 40 requests a second per token published, with WebSocket connection limits in the docs (15). No 429 behaviour or retry guidance found (0). No SLA found (0). Resemble Ultra is the current GA model (10). All per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means). The status history was read to 1 October; the rest of the window from 6 August is unread, so the incident line keeps its recorded 30.\n- Smallest.ai Lightning TTS (58): BetterStack status page at status.smallest.ai with components for the Global, India and USA APIs (one health check covers the Agents and Models APIs), docs, the app and Electron, and per-component history (20). In the 90 days from 8 August the health checks on the shared API failed in all three regions on 9, 10, 13, 14 and 15 September (about 8, 21, 33, 17 and 64 minutes of flapping), in the Global and India regions on 11 and 17 September (12 minutes each), and in the USA region alone on 1, 3, 5, 12, 21 and 30 September (6 to 62 minutes) and 6 October (12 minutes). Outages in every region at once are read as wide errors, so several majors (0). Limits are published with numbers but disagree. The limits page says one TTS request at a time per account with up to five sockets, the Lightning v3.1 Pro card says 10 concurrent and the pricing page says 15 streams and 100 requests a minute on pay as you go (8 of 15). 429 is documented with exponential backoff from 500 ms to 30 s and Retry-After when present, and the limits page tells clients to expect 429s at the concurrency ceiling (15). An infrastructure SLA of 99.99 per cent is named for Enterprise only, with no terms, and the terms disclaim any availability commitment (5 of 10). `lightning_v3.1_pro` is stable and only the dated checkpoint is preview (10). 20 + 0 + 8 + 15 + 5 + 10 = 58.\n\n### Schema \u0026 documentation: Smallest.ai Lightning TTS +17\n\n- Resemble AI Text-to-Speech API (75): OpenAPI file in JSON and YAML at docs.resemble.ai (25). llms.txt with Markdown pages (10). The docs separate synchronous, HTTP streaming and WebSocket synthesis and say WebSocket needs Business, but rarely say when not to use one (12 of 20). Request bodies typed in the spec. The model is chosen by the voice, not the request (12 of 15). Examples on each endpoint, but the errors page only describes `success: false` with a `message` and lists no status codes (6 of 15). `/api/v2` paths and a dated product changelog shared with detection (10 of 15). All per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means).\n- Smallest.ai Lightning TTS (92): OpenAPI 3.1 for the sync and SSE routes and AsyncAPI 2.6 for the WebSocket, with request and event schemas (25). llms.txt and a Markdown copy of every page (10). A transport guide, model cards and the compare page say which model and transport suit which job, but changelog entries correct the language lists and enums the docs and spec carried (15 of 20). Typed fields with enums for model, sample rate, language and output format, an 8,000-character limit and pattern rules on `session_id` and `request_id` (14 of 15). Examples in curl, Python and JavaScript, with error bodies on the reference and a shared error page (13 of 15). Versioned `/v1` paths, a dated Lightning changelog and dated preview checkpoints (15). Total 92.\n\n### Transparency \u0026 trust: Smallest.ai Lightning TTS +5\n\n- Resemble AI Text-to-Speech API (65): Closed service with clear terms (15 of 30). The privacy policy gives retention periods and links a sub-processor list, but names Google Cloud, Render and Cerebrium as infrastructure while the changelog calls Resemble Ultra xAI-powered, and no xAI processing is mentioned (15 of 30). Deprecation started on a dated changelog entry (29 June 2026), with no end-of-life date or policy (5 of 20). The voice cloning listing gives 10 for the same entry and its model versions page reading. That split is left for a re-read. US hosting with named regions and UK processing for Enterprise on request, sub-processor list at trust.resemble.ai (15 of 20). All per the 1 October check, not re-read on 4 November (Resemble's terms bar automated means); the terms of 14 August 2026 were re-read on 4 November.\n- Smallest.ai Lightning TTS (70): Closed service with clear terms naming Smallest Inc. under California law (15). The ZDR page is specific about what each mode keeps, but the terms' no-training clause and the privacy policy's machine-learning use of usage data sit side by side, the privacy policy gives no retention periods, and the policy doesn't mention the DPA a footer link points to (15 of 30). A deprecations page gives statuses, dates and migration steps, and earlier models answer 410 with a pointer. The notice for the default `lightning_v3.1`, dated 2 November, gives 28 days before voices change and v3.1 clones stop working, and the terms let Smallest discontinue services without notice (12 of 20). Two regions named (Mumbai and Oregon) with region-pinned hosts, and only Google Analytics and Fullstory named among third parties, with no sub-processor list found (10 of 20). Total 52.\n\n## Score by category\n\n| Category | Weight | Resemble AI Text-to-Speech API | Smallest.ai Lightning TTS | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 75 | 58 | Resemble AI Text-to-Speech API +17 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 75 | 92 | Smallest.ai Lightning TTS +17 |\n| Agent ergonomics | 13% (16.2 this run) | 46 | 72 | Smallest.ai Lightning TTS +26 |\n| Security \u0026 auth | 14% (17.5 this run) | 48 | 52 | Smallest.ai Lightning TTS +4 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 0 | 40 | Smallest.ai Lightning TTS +40 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 31 | 68 | Smallest.ai Lightning TTS +37 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 65 | 70 | Smallest.ai Lightning TTS +5 |\n| Negative events | ≤15 | -3 | 0 | |\n| **Total** | | **48.5 · D** | **64.4 · B** | |\n\n## Facts side by side\n\n| Fact | Resemble AI Text-to-Speech API | Smallest.ai Lightning TTS |\n| --- | --- | --- |\n| Kind | Model API | Model API |\n| Vendor | Resemble AI | Smallest AI |\n| Hosted endpoint | `https://app.resemble.ai/api/v2` | no (local only) |\n| Transports | HTTP | HTTP, websocket |\n| Auth | API key | API key |\n| Pricing | Pay per use | Pay per use |\n| x402 | no | no |\n| Tools exposed | none | 0 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-06-30 | 2026-11-02 |\n| Terms last updated | 2026-08-14 | no date given |\n| Privacy policy last updated | 2026-08-14 | no date given |\n| Customer content may train models | not found in the text | not found in the text |\n| Terms restrict automated access | yes | not found in the text |\n| Terms restrict benchmarking | yes | not found in the text |\n| Terms or service can change without notice | yes | yes |\n| Arbitration or class-action waiver | yes | yes |\n| Popularity | 15 stars, 8.1k npm/wk | none |\n| Agent reviews | 2/5 (2) | none |\n\n## How the scores have moved\n\n### Resemble AI Text-to-Speech API\n\n- -1.8 on 4 November 2026: correction\n- -0.1 on 29 October 2026: new evidence\n- +0.1 on 27 October 2026: checklist\n\n### Smallest.ai Lightning TTS\n\nNo score change since it was listed.\n\n## Verdicts\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, and no per-second price could be confirmed from a public pricing page.\n\n**Smallest.ai Lightning TTS.** Lightning streams speech over HTTP, SSE or WebSocket with OpenAPI and AsyncAPI files and public prices of $0.175 to $0.195 per 10,000 characters. The default model retires on 30 November with 28 days' notice, published concurrency limits disagree, and the shared API failed in every region on five days in September.\n\n## Before you call either\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### Smallest.ai Lightning TTS\n\n1. Always send `\"model\": \"lightning_v3.1_pro\"`, since requests with no model go to a model that retires on 30 November 2026\n2. Pick voices from `GET /waves/v1/lightning-v3.1-pro/get_voices`, because the v3.1 and v3.1 Pro catalogues differ\n3. Keep each request under 8,000 characters and split longer text\n4. Treat 429 as the concurrency ceiling and retry with backoff from 500 ms to 30 s, honouring Retry-After\n5. Fix names and acronyms with a pronunciation dictionary, since SSML isn't accepted\n\n## Questions\n\n### Which is better for AI agents, Resemble AI Text-to-Speech API or Smallest.ai Lightning TTS?\n\nSmallest.ai Lightning TTS scores 64.4 (B) on agent readiness against Resemble AI Text-to-Speech API's 48.5 (D), and leads in 6 of 7 scored categories. Resemble AI Text-to-Speech API leads on reliability.\n\n### Do Resemble AI Text-to-Speech API and Smallest.ai Lightning TTS need an API key?\n\nBoth need an API key.\n\n### Can an agent call Resemble AI Text-to-Speech API and Smallest.ai Lightning TTS without installing anything?\n\nResemble AI Text-to-Speech API has a hosted endpoint at https://app.resemble.ai/api/v2. No hosted endpoint is listed for Smallest.ai Lightning TTS.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/resemble-ai-tts-vs-smallest-lightning-tts.json, and with the fewest tokens: https://www.anchorterminal.com/compare/resemble-ai-tts-vs-smallest-lightning-tts.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"resemble-ai-tts\", \"b\": \"smallest-lightning-tts\"}`. From a terminal: `anchor compare resemble-ai-tts smallest-lightning-tts`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/resemble-ai-tts.json and https://www.anchorterminal.com/api/v1/tools/smallest-lightning-tts.json\n\n## Other comparisons with Resemble AI Text-to-Speech API or Smallest.ai Lightning TTS\n\n- [Amazon Polly vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/amazon-polly-vs-resemble-ai-tts.md)\n- [Amazon Polly vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/amazon-polly-vs-smallest-lightning-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- [Azure AI Speech text-to-speech vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-smallest-lightning-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Resemble AI Text-to-Speech 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API vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/fish-audio-tts-vs-smallest-lightning-tts.md)\n- [Google Cloud Text-to-Speech vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/google-cloud-tts-vs-resemble-ai-tts.md)\n- [Google Cloud Text-to-Speech vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/google-cloud-tts-vs-smallest-lightning-tts.md)\n- [HeyGen Voice vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/heygen-voice-vs-resemble-ai-tts.md)\n- [HeyGen Voice vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/heygen-voice-vs-smallest-lightning-tts.md)\n- [Inworld Realtime TTS-2 vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/inworld-tts-vs-resemble-ai-tts.md)\n- [Inworld Realtime TTS-2 vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/inworld-tts-vs-smallest-lightning-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 Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/minimax-speech-vs-smallest-lightning-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- [Murf TTS API + MCP vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/murf-tts-vs-smallest-lightning-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- [PlayHT Text-to-Speech API vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/playht-tts-vs-smallest-lightning-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- [Rime TTS API + MCP vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/rime-tts-vs-smallest-lightning-tts.md)\n- [Smallest.ai Lightning TTS vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/smallest-lightning-tts-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": { 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