{ "data": { "a": { "slug": "inworld-voice-cloning", "name": "Inworld Instant Voice Cloning", "vendor": "Inworld AI", "vendorUrl": "https://inworld.ai", "kind": "model", "category": "voice-cloning", "summary": "Inworld's Instant Voice Cloning API makes a reusable text-to-speech voice from 3 to 30 seconds of audio in one synchronous call, for Inworld's TTS-2 models. The same operation is in the Inworld CLI and its bundled MCP server.", "url": "https://www.anchorterminal.com/tools/inworld-voice-cloning", "markdownUrl": "https://www.anchorterminal.com/tools/inworld-voice-cloning.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/inworld-voice-cloning.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/inworld-voice-cloning.json", "dns": "inworld-voice-cloning.grade.anchorterminal.com", "repo": "https://github.com/inworld-ai/inworld-api-examples", "license": "Proprietary service under Inworld's Terms of Service. The `@inworld/cli` and `@inworld/tts` npm packages and the examples repository are MIT", "transports": [ "http", "stdio", "streamable-http" ], "remoteUrl": "https://api.inworld.ai", "packages": [ { "registry": "npm", "name": "@inworld/cli" }, { "registry": "npm", "name": "@inworld/tts" }, { "registry": "pypi", "name": "inworld-tts" } ], "auth": "api-key", "authNotes": "Self-serve workspace API key from the Portal or `inworld workspace add-key`, sent as `Authorization: Basic` with the Base64 credential as copied. Keys are read-only for the Voice API by default, and cloning, updating and deleting voices need the write toggle, which can be changed on an existing key. Deleting a key revokes it. One-time tokens minted from a key serve browser and mobile clients.", "pricing": "freemium", "pricingNotes": "Creating an instant clone has no charge in the docs or on the pricing page. Speech from a clone costs $25 per million characters on TTS-2 or $15 on TTS-2 Flash on the free On-Demand plan, falling on the $25, $100, $300 and $1,500 monthly plans. On-Demand allows 100 custom voices and 2 cloning requests a minute (checked 2026-11-06).", "priceSummary": "$25 / mo", "where": "both", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs, llms.txt or the pricing page (checked 2026-11-06). Credits are bought at a checkout page, $10 minimum.", "endpoints": [] }, "toolCount": 40, "popularity": { "githubStars": null, "npmWeekly": 3632, "pypiWeekly": null, "asOf": "2026-11-06" }, "docsUrl": "https://docs.inworld.ai/tts/instant-voice-cloning", "llmsTxt": "https://docs.inworld.ai/llms.txt", "capabilities": [ "voice.clone", "voice.design", "speech.tts" ], "tags": [ "hosted", "official", "freemium", "free-tier", "no-card", "closed-source", "python", "typescript", "llms-txt", "mcp", "cli", "status-page", "soc2" ], "lastRelease": "2026-10-29", "graded": true, "anchor": { "graded": true, "score": 61.9, "grade": "C", "agentReady": false, "rank": 585, "ranked": true, "rankOf": 1486, "categoryRank": 4, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 64, "maintenance": 68, "payments": 40, "reliability": 75, "schema": 64, "security": 55, "transparency": 63 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-06" }, "negative": 0, "verdict": "One JSON call returns a usable voice ID from 3 to 30 seconds of audio, with no charge per clone and 100 custom voices on the free plan, behind keys that are read-only until write access is switched on. The API has no consent field, and Zero Data Retention excludes cloning samples.", "bestFor": "Teams already using Inworld TTS-2 that want clones from a short clip through one call, the CLI or MCP.", "strengths": [ "Synchronous clone from 3 to 30 seconds of WAV or MP3 audio, with language auto-detection and optional background-noise removal", "No charge per clone. The free On-Demand plan includes instant cloning and 100 custom voices, and speech is $25 per million characters on TTS-2", "API keys are read-only by default. Cloning, updating and deleting voices need a write toggle that can be changed on an existing key", "`GET /voices/v1/voices` filters by `source = \"IVC\"` with paging, and `voices:customVoiceCapacity` reports how many custom voices remain", "`llms.txt`, `llms-full.txt` and a Markdown twin of every docs page, plus `clone_voice` in the MCP server in `@inworld/cli` 1.5.0 (29 October 2026)" ], "weaknesses": [ "No consent, verification or watermark field in the clone API. Only the Portal flow asks the user to confirm rights to the voice", "Zero Data Retention does not cover cloning audio samples, and no retention period for them was found", "No idempotency key on `POST /voices/v1/voices:clone`, and no error list for the Voice API", "No OpenAPI file is linked from the docs, and the repositories named in the npm metadata of the CLI and Node SDK are not public", "The MCP `clone_voice` description says about 5 seconds and 4 MB a sample, while the docs say 3 seconds and 12 MB" ], "agentNotes": [ "Create the key with write access (`inworld workspace add-key --write`). A default key gets code 7, insufficient access level, on `voices:clone`", "Send the complete Base64 credential as `Authorization: Basic $INWORLD_API_KEY`. Don't encode it again", "Send one 10 to 30 second WAV or MP3 clip as base64 in `voiceSamples[].audioData`. Audio past 30 seconds is cut", "Don't blind-retry a clone. There's no idempotency key, so list voices with `filter=source=\"IVC\"` first, and back off with jitter on 429", "Set `gender`, `ageGroup` and `categories` with UpdateVoice afterwards. The clone call ignores them without an error", "The response echoes up to 15 seconds of processed audio as base64 in `audioSamplesValidated`. Drop it before passing the result to a model" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 61.9 } ], "editorialScores": { "ergonomics": 64, "maintenance": 68, "payments": 40, "reliability": 75, "schema": 64, "security": 55, "transparency": 51 }, "provenanceScore": 75, "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": "npm install -g @inworld/cli", "http": "curl --location 'https://api.inworld.ai/voices/v1/voices:clone' \\\n --header \"Authorization: Basic $INWORLD_API_KEY\" \\\n --header 'Content-Type: application/json' \\\n --data '{\"displayName\": \"my_voice_clone_demo\", \"languageCode\": \"en-US\", \"voiceSamples\": [{\"audioData\": \"\u003cbase64-audio-data\u003e\"}]}'", "claudeCode": "claude mcp add inworld -- inworld mcp", "config": { "mcpServers": { "Inworld": { "args": [ "mcp" ], "command": "inworld" } } } }, "letme": { "capability": "https://letme.dev/voice.clone", "tool": "https://letme.dev/inworld-voice-cloning" }, "sameCompany": [ "inworld-stt", "inworld-tts", "inworld-realtime" ], "area": "voice", "unitPrices": [ { "item": "Speech from a clone, TTS-2, On-Demand", "unit": "1m-chars", "usd": 25, "note": "$20, $17.50, $15 and $12.50 on the monthly plans" }, { "item": "Speech from a clone, TTS-2 Flash, On-Demand", "unit": "1m-chars", "usd": 15, "note": "$10 down to $7 on the monthly plans" }, { "item": "Creator plan", "unit": "month", "usd": 25, "note": "credits equal to the price, 500 custom voices, 3 clone requests a minute" }, { "item": "Builder plan", "unit": "month", "usd": 100, "note": "3,000 custom voices, 5 clone requests a minute" }, { "item": "Developer plan", "unit": "month", "usd": 300, "note": "10,000 custom voices, 10 clone requests a minute" }, { "item": "Growth plan", "unit": "month", "usd": 1500, "note": "30,000 custom voices, 20 clone requests a minute" } ], "provenance": { "legalEntity": "Theai, Inc. dba Inworld AI", "domain": "inworld.ai", "domainRegistered": "", "endpointOnVendorDomain": true, "terms": "https://inworld.ai/terms", "privacy": "https://inworld.ai/privacy", "statusPage": "https://status.inworld.ai", "changelog": "https://docs.inworld.ai/release-notes/tts", "securityTxt": "none", "checked": "2026-11-06", "notes": [ "The Terms of Service (effective 11 June 2025, re-read 6 November 2026) are an agreement with Theai, Inc. dba Inworld AI under California law. They carry no clause on robots or automated access, and none specific to voice cloning.", "inworld.ai's robots.txt carries `Content-Signal: ai-train=no, search=yes, ai-input=no`, recorded as a fact about the site. Since 30 October 2026 this is not a reason to hold, so this listing, held on 9 October for it, is graded.", "status.inworld.ai draws incidents from GitHub issues in inworld-ai/inworld-issue-status, read through the GitHub API on 6 November.", "inworld.ai/.well-known/security.txt returned 404 on 30 October per the inworld-tts check. The security page links a vulnerability report form." ], "score": 75 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/inworld-voice-cloning.json", "live": { "slug": "inworld-voice-cloning", "probe": { "target": "https://api.inworld.ai", "method": "get", "lastAt": "2026-11-07T18:20:32.661612863Z", "lastOk": true, "lastStatus": 200, "lastMs": 178, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 136, "p95ms24h": 266, "samples24h": 200, "samples30d": 200, "days": [ { "date": "2026-11-06", "probes": 13, "ok": 13 }, { "date": "2026-11-07", "probes": 187, "ok": 187 } ] }, "versions": [ { "registry": "npm", "name": "@inworld/cli", "version": "1.5.0", "seenAt": "2026-11-06T23:35:10.767231519Z" }, { "registry": "npm", "name": "@inworld/tts", "version": "1.1.1", "seenAt": "2026-11-06T23:35:12.902766977Z" }, { "registry": "pypi", "name": "inworld-tts", "version": "1.2.1", "released": "2026-05-06", "seenAt": "2026-11-06T23:35:14.803764179Z" } ], "githubStars": 66, "npmWeekly": 290, "pypiWeekly": 4010, "securityTxt": { "url": "https://inworld.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-11-07T16:01:11.794771951Z" }, "llmsTxt": { "url": "https://docs.inworld.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:32:51.758972379Z" }, "updatedAt": "2026-11-07T18:20:32.661612863Z" } }, "answer": "Inworld Instant Voice Cloning scores 61.9 (C) on agent readiness against Smallest.ai Instant Voice Clone's 58 (C), and leads in 4 of 7 scored categories. Smallest.ai Instant Voice Clone leads on schema \u0026 documentation and transparency \u0026 trust.", "b": { "slug": "smallest-voice-clone", "name": "Smallest.ai Instant Voice Clone", "vendor": "Smallest, Inc.", "vendorUrl": "https://smallest.ai", "kind": "model", "category": "voice-cloning", "summary": "Smallest.ai's instant voice cloning API creates a reusable voice for its Lightning text-to-speech models from a 5 to 15 second sample in one multipart POST, returning the voice ID and sample clips of the cloned voice.", "url": "https://www.anchorterminal.com/tools/smallest-voice-clone", "markdownUrl": "https://www.anchorterminal.com/tools/smallest-voice-clone.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/smallest-voice-clone.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/smallest-voice-clone.json", "dns": "smallest-voice-clone.grade.anchorterminal.com", "license": "Proprietary service under Smallest's Terms of Service. The `smallestai` Python SDK is on PyPI", "transports": [ "http" ], "remoteUrl": "https://api.smallest.ai/waves/v1/voice-cloning", "packages": [ { "registry": "pypi", "name": "smallestai" } ], "auth": "api-key", "authNotes": "Bearer API key created in the Smallest dashboard after a browser signup, shown once, revoked by deleting it. Keys have no scopes. Short-lived access tokens minted from a key work on TTS, STT and speech-to-speech routes but are not accepted on the cloning endpoint.", "pricing": "usage", "pricingNotes": "No price per clone is published. Speech from a clone is about $0.175 per 10,000 characters on Lightning v3.1 and $0.195 on v3.1 Pro, pay as you go. The agents pricing page states $10 in free credits. The models pricing table marks voice cloning No on pay as you go, while the docs let any API key clone (checked 2026-11-06).", "priceSummary": "Pay per use", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs, llms.txt or the pricing pages (checked 2026-11-06).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-11-06" }, "docsUrl": "https://docs.smallest.ai/models/voice-cloning/instant-clone-api", "llmsTxt": "https://docs.smallest.ai/llms.txt", "capabilities": [ "voice.clone", "speech.tts" ], "tags": [ "hosted", "official", "closed-source", "usage", "python", "llms-txt", "status-page", "enterprise", "data-residency" ], "lastRelease": "2026-10-29", "graded": true, "anchor": { "graded": true, "score": 58, "grade": "C", "agentReady": false, "rank": 768, "ranked": true, "rankOf": 1486, "categoryRank": 8, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 62, "maintenance": 72, "payments": 20, "reliability": 65, "schema": 70, "security": 48, "transparency": 72 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-06" }, "negative": 0, "verdict": "One multipart POST clones a voice from 5 to 15 seconds of audio and returns sample clips, with dated deprecation notices and current changelog entries. The endpoint still defaults to a model whose clones stop working on 30 November 2026, there's no consent field or clone price, and the status feed shows frequent short API outages.", "bestFor": "Teams already on Smallest's Lightning TTS or voice agents who want a clone from a short clip in one call.", "strengths": [ "Synchronous clone from 5 to 15 seconds of audio that returns the voice ID and signed URLs to sample clips of the new voice", "Seven documented error cases with causes, including `voice_clone_timeout` and `voice_clone_error` codes", "A deprecation page dates every retirement and gives the migration steps for clones", "The Terms say customer content isn't used for training, and India and USA region hostnames are documented", "llms.txt and a Markdown copy of every docs page" ], "weaknesses": [ "The endpoint defaults to `lightning-v3.1`, whose clones stop working on 30 November 2026", "No consent or verification field, and no price per clone or clone limit published", "The pricing table marks voice cloning unavailable on pay as you go, while the docs let any key clone", "status.smallest.ai lists dozens of short API outages in 90 days, with a cluster across every region on 13 to 17 September 2026", "No idempotency key, no pagination on the clone list, and plain unscoped API keys" ], "agentNotes": [ "Always pass `model=lightning-v3.1-pro`. The default `lightning-v3.1` clones stop working on 30 November 2026", "Use the returned `voiceId` with the matching TTS model and check `modelIds` from `GET /waves/v1/voice-cloning` if a TTS call returns a tiny WAV", "Before retrying a `voice_clone_timeout`, list clones by `displayName` so a retry doesn't create a duplicate", "Send the server API key, not an access token. The cloning endpoint refuses short-lived tokens", "Keep TTS calls from a clone to one at a time on the self-serve plan and back off on 429" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 58 } ], "editorialScores": { "ergonomics": 62, "maintenance": 72, "payments": 20, "reliability": 65, "schema": 70, "security": 48, "transparency": 57 }, "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/voice-cloning\" \\\n -H \"Authorization: Bearer $SMALLEST_API_KEY\" \\\n -F \"displayName=my-custom-voice\" \\\n -F \"file=@/path/to/sample.wav\" \\\n -F \"model=lightning-v3.1-pro\" \\\n -F \"language=en\"" }, "letme": { "capability": "https://letme.dev/voice.clone", "tool": "https://letme.dev/smallest-voice-clone" }, "sameCompany": [ "smallest-pulse-stt", "smallest-lightning-tts" ], "area": "voice", "unitPrices": [ { "item": "Speech from a clone, Lightning v3.1", "unit": "1m-chars", "usd": 17.5, "note": "about $0.175 per 10,000 characters, pay as you go" }, { "item": "Speech from a clone, Lightning v3.1 Pro", "unit": "1m-chars", "usd": 19.5, "note": "about $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. under California law with arbitration. The Privacy Policy and Prohibited Use Policy are effective 18 September 2026.", "The Prohibited Use Policy bars data mining, robots or scraping except as the site's robots.txt allows. smallest.ai/robots.txt allows ClaudeBot and all agents on the pages read and sets `Content-Signal: ai-train=yes, search=yes, ai-input=yes`.", "security.txt at smallest.ai/.well-known/security.txt is valid until 31 December 2026, with security@smallest.ai.", "RDAP gives smallest.ai a registration date of 2 September 2023.", "trust.smallest.ai did not answer through our proxy (502) and smallest.ai/security returns 404." ], "score": 87 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/smallest-voice-clone.json", "live": { "slug": "smallest-voice-clone", "probe": { "target": "https://api.smallest.ai/waves/v1/voice-cloning", "method": "get", "lastAt": "2026-11-07T18:20:55.191256377Z", "lastOk": true, "lastStatus": 401, "lastMs": 378, "lastNote": "asks for credentials", "authRequired": true, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 361, "p95ms24h": 429, "samples24h": 200, "samples30d": 200, "days": [ { "date": "2026-11-06", "probes": 13, "ok": 13 }, { "date": "2026-11-07", "probes": 187, "ok": 187 } ] }, "vendorStatus": { "page": "https://status.smallest.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-11-07T04:48:45.839717169Z" }, "versions": [ { "registry": "pypi", "name": "smallestai", "version": "5.14.0", "released": "2026-10-07", "seenAt": "2026-11-07T00:06:42.794457962Z" } ], "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": "2026-11-07T15:34:00.872777157Z" }, "updatedAt": "2026-11-07T18:20:55.191256377Z" } }, "edges": [ { "by": 20, "category": "payments", "leads": "inworld-voice-cloning", "name": "Payments \u0026 pricing", "reasons": { "a": "No x402, MPP or L402 (0). The pricing page, unread on 9 October and read on 6 November, publishes per-character rates for speech from a clone, $25 per million characters on TTS-2 and $15 on TTS-2 Flash on the free plan, and no charge for creating a clone (20, was 10). The On-Demand plan is free with 100 custom voices and instant cloning, and no card is asked for (20). `inworld login` opens a browser and signup is a human flow. The CLI mints keys only after that (0). 0+20+20+0 = 40.", "b": "No x402, MPP or L402 (0). Per-character TTS prices are public, about $0.175 per 10,000 characters on Lightning v3.1, but no price per clone is published and the models pricing table marks voice cloning No on pay as you go, against the docs (10). The agents pricing page states $10 in free credits, and whether a card is needed wasn't established (10 of 20). A person signs up in a browser and creates the key in the dashboard (0). 0+10+10+0 = 20." }, "scores": { "a": 40, "b": 20 } }, { "by": 10, "category": "reliability", "leads": "inworld-voice-cloning", "name": "Reliability", "reasons": { "a": "Graded on the REST API, the surface an agent would call. Status page at status.inworld.ai, drawn from GitHub issues, with five components and none for cloning (20). Read through the GitHub API on 6 November, the 90 days from 8 August hold two incidents, 29 minutes of elevated TTS latency on 25 August and 26 minutes of elevated TTS 2.1 errors from a network fault at one GPU site on 28 October, both minor (20). Cloning limits are published per plan, 2 to 20 requests a minute (15). A 429 is documented with exponential backoff and jitter code, and since the 9 October check the rate-limits page says limits over a minute can carry `Retry-After`. No idempotency key or safe-retry guidance for clone creation (10 of 15, was 9). The pricing page, now read, names an SLA on Enterprise only with no terms or figure, as on inworld-tts (0). Instant cloning carries no Preview or Beta mark (10). 20+20+15+10+0+10 = 75.", "b": "Graded on the hosted cloning API with the hosted lines. status.smallest.ai is the vendor's own status page with components per region and a dated incident feed (20). The feed, read on 6 November, has dozens of automated outage alerts on the API components in the 90 days from 8 August, most a few minutes long, and a cluster across every API region from 13 to 17 September. The 60-day uptime bars read 99.790 per cent for API USA and 99.849 per cent for API Global. No single outage of an hour was found, but repeated wide outages read as one major episode (10). Rate limits are published for TTS (one concurrent request, 100 a minute on pay as you go), while the per-organisation clone limit has no number (10 of 15). The limits page says to handle 429 gracefully and the clone errors say to retry a timeout, with no Retry-After, backoff figures or idempotency key (5 of 15). The pricing table lists an Enterprise SLA of 99.99 per cent (10). Instant cloning carries no beta label (10). 20+10+10+5+10+10 = 65." }, "scores": { "a": 75, "b": 65 } }, { "by": 9, "category": "transparency", "leads": "smallest-voice-clone", "name": "Transparency \u0026 trust", "reasons": { "a": "Closed service with clear terms naming Theai, Inc. dba Inworld AI, read on 6 November (unread on 9 October because of the Content-Signal line), and MIT client packages on npm (15 of 30, was 8). The Zero Data Retention page is specific that cloning samples are retained to build the voice, but gives no period, and the Terms' no-training clause and the Privacy Notice's training use sit side by side without a reconciling sentence, as on inworld-tts (14 of 30). Dated notices in the docs, `inworld-tts-1` discontinued on 15 June 2026 and the 30-second clone limit from 15 August, with release stages defined and no written notice period (12 of 20). US by default with isolated EU and India regions on Enterprise. No sub-processor list was found in the docs (10 of 20). 15+14+12+10 = 51.", "b": "Closed service with clear terms naming Smallest, Inc. under California law, effective 21 October 2026 (15 of 30). The Terms rule out training on customer content, the Privacy Policy (18 September 2026) gives retention criteria but no periods, and the Zero Data Retention page is specific about Enterprise options, with nothing on how long cloning samples are kept (16 of 30). A deprecation page with dated statuses (deprecated, rejects, removed, scheduled, retiring) and migration targets (16 of 20). Two regions named with locations. No sub-processor list was found and a DPA page exists unread (10 of 20). 15+16+16+10 = 57." }, "scores": { "a": 63, "b": 72 } }, { "by": 7, "category": "security", "leads": "inworld-voice-cloning", "name": "Security \u0026 auth", "reasons": { "a": "Graded for voice cloning as the other listings in this category were, with consent and misuse controls in place of the read-only line and training and retention of voice data in place of the prompt-injection line. Revocable workspace keys that are read-only for the Voice API until a write toggle is set, Realtime-only keys and single-use tokens, sent in a header (25 of 30). The API has no consent or verification field and no watermark was found. Only the Portal asks the user to confirm rights, and the Terms (11 June 2025), now read, have no clause on cloned voices. The write toggle keeps a default key from cloning (6 of 20). The Terms say Inworld won't train generally available models on non-public Materials except feedback and trust and safety content, while the Privacy Notice lists training among its uses. Zero Data Retention excludes cloning samples and no retention period for them is published (7 of 15, was 4). Usage is attributed per key in the dashboard and an experimental usage records endpoint exists from the Builder plan. No audit log found (7 of 15). GDPR and SOC 2 Type II are stated on every plan on the pricing page, and the security page links a vulnerability report form. No security.txt (404 per the 30 October inworld-tts check) and no bug bounty found (10 of 20, was 8). 25+6+7+7+10 = 55.", "b": "Graded for voice cloning as the other listings in this category, with consent and misuse controls in place of the read-only line and training and retention of voice data in place of the prompt-injection line. Plain bearer keys, shown once, revocable, with rotation guidance and no scopes. Short-lived access tokens are refused on the cloning endpoint (20 of 30). No consent or verification field. The Terms let Smallest demand proof that the speaker authorised a clone and remove voices without it, and the prohibited use policy bars unauthorised impersonation. No watermark found (6 of 20). The Terms say Smallest won't use User Content or Input to train its services. Zero retention and retention windows are Enterprise options, and no retention period for samples is published (9 of 15). A usage dashboard, with no audit log found (5 of 15). A valid security.txt naming security@smallest.ai and a HIPAA business associate agreement page. The trust centre didn't answer through our proxy, so no certification was confirmed first-hand, and no bug bounty was found (8 of 20). 20+6+9+5+8 = 48." }, "scores": { "a": 55, "b": 48 } }, { "by": 6, "category": "schema", "leads": "smallest-voice-clone", "name": "Schema \u0026 documentation", "reasons": { "a": "No OpenAPI file is linked from the docs or `llms.txt`, re-read on 6 November. The MCP server has typed inputs on all 40 tools, which earns part of the line (10 of 25). `llms.txt`, `llms-full.txt` and Markdown twins (10). The guides say when to use instant cloning, Professional Voice Cloning or Voice Design, and the reference warns which fields are ignored (15 of 20). Required fields and base64 audio are typed, and a new `languageCode` string is validated against the catalogue with `INVALID_ARGUMENT`, while size and length limits sit in prose and the MCP tool still states different ones (10 of 15). Examples in curl, Python, JavaScript and the CLI, with one error response shown and no error list for the Voice API (9 of 15). A `/v1/` path and dated TTS release notes, newest 11 September, with no changelog for the Voice API itself (10 of 15). 10+10+15+10+9+10 = 64.", "b": "The API reference pages are generated with typed fields, enums and error schemas, but no OpenAPI file was found linked from the docs or llms.txt (5 of 25). llms.txt and a Markdown copy of every page (10). The guide says when to use the Pro pool, how to check `modelIds` before synthesis and why a mismatched clone returns empty audio, while the reference still names the retiring default (14 of 20). `model` and `language` are enums validated by the server, with required `displayName` and `file`, a 5 MB limit and MIME types listed, and `tags` as a comma-separated string (12 of 15). Examples in curl, Python and Node.js and a table of seven error cases with causes (14 of 15). Paths under `/v1`, a deprecation page with dated statuses and a models changelog with entries on 21, 24, 26, 28 and 29 October 2026 (15). 5+10+14+12+14+15 = 70." }, "scores": { "a": 64, "b": 70 } } ], "facts": [ { "a": "Model API", "b": "Model API", "name": "Kind" }, { "a": "Inworld AI", "b": "Smallest, Inc.", "name": "Vendor" }, { "a": "https://api.inworld.ai", "b": "https://api.smallest.ai/waves/v1/voice-cloning", "name": "Hosted endpoint" }, { "a": "HTTP, stdio, Streamable HTTP", "b": "HTTP", "name": "Transports" }, { "a": "API key", "b": "API key", "name": "Auth" }, { "a": "Freemium", "b": "Pay per use", "name": "Pricing" }, { "a": "$15 per 1M characters", "b": "$17.50 per 1M characters", "name": "Price for voice cloning" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Proprietary service under Inworld's Terms of Service. The `@inworld/cli` and `@inworld/tts` npm packages and the examples repository are MIT", "b": "Proprietary service under Smallest's Terms of Service. The `smallestai` Python SDK is on PyPI", "name": "Licence" }, { "a": "40", "b": "none", "name": "Tools exposed" }, { "a": "yes", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-10-29", "b": "2026-10-29", "name": "Last release" }, { "a": "2025-06-11", "b": "no date given", "name": "Terms last updated" }, { "a": "2026-01-18", "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": "not found in the text", "b": "not found in the text", "name": "Terms restrict automated access" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict benchmarking" }, { "a": "not found in the text", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "not found in the text", "b": "yes", "name": "Arbitration or class-action waiver" }, { "a": "3.6k npm/wk", "b": "none", "name": "Popularity" } ], "faq": [ { "answer": "Inworld Instant Voice Cloning scores 61.9 (C) on agent readiness against Smallest.ai Instant Voice Clone's 58 (C), and leads in 4 of 7 scored categories. Smallest.ai Instant Voice Clone leads on schema \u0026 documentation and transparency \u0026 trust.", "question": "Which is better for AI agents, Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone?" }, { "answer": "Inworld Instant Voice Cloning, at $15 per 1M characters against $17.50 per 1M characters for Smallest.ai Instant Voice Clone. These are the vendors' published prices for the job.", "question": "Which is cheaper for voice cloning, Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone?" }, { "answer": "Both need an API key.", "question": "Do Inworld Instant Voice Cloning and Smallest.ai Instant Voice Clone need an API key?" }, { "answer": "Yes. Inworld Instant Voice Cloning has a hosted endpoint at https://api.inworld.ai and Smallest.ai Instant Voice Clone at https://api.smallest.ai/waves/v1/voice-cloning.", "question": "Can an agent call Inworld Instant Voice Cloning and Smallest.ai Instant Voice Clone without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 75 against 65", "Security \u0026 auth, 55 against 48", "Payments \u0026 pricing, 40 against 20" ], "also": [ "Cheaper for voice cloning, $15 against $17.50 per 1M characters", "Runs on your own machine", "Free to start without a card" ], "goodFor": "Teams already using Inworld TTS-2 that want clones from a short clip through one call, the CLI or MCP.", "slug": "inworld-voice-cloning", "watchFor": "No consent, verification or watermark field in the clone API. Only the Portal flow asks the user to confirm rights to the voice" }, { "aheadOn": [ "Schema \u0026 documentation, 70 against 64", "Transparency \u0026 trust, 72 against 63" ], "also": null, "goodFor": "Teams already on Smallest's Lightning TTS or voice agents who want a clone from a short clip in one call.", "slug": "smallest-voice-clone", "watchFor": "The endpoint defaults to `lightning-v3.1`, whose clones stop working on 30 November 2026" } ], "history": null, "job": { "capability": "voice.clone", "name": "Voice cloning" }, "others": [ { "json": "https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-inworld-voice-cloning.json", "title": "Cartesia Voice Cloning API + MCP vs Inworld Instant Voice Cloning", "url": "https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-inworld-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-smallest-voice-clone.json", "title": "Cartesia Voice Cloning API + MCP vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-voice-cloning-vs-inworld-voice-cloning.json", "title": "ElevenLabs Voice Cloning and Voice Design API vs Inworld Instant Voice Cloning", "url": "https://www.anchorterminal.com/compare/elevenlabs-voice-cloning-vs-inworld-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-voice-cloning-vs-smallest-voice-clone.json", "title": "ElevenLabs Voice Cloning and Voice Design API vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/elevenlabs-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-inworld-voice-cloning.json", "title": "Fish Audio Voice Cloning API vs Inworld Instant Voice Cloning", "url": "https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-inworld-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-smallest-voice-clone.json", "title": "Fish Audio Voice Cloning API vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/gradium-voice-cloning-vs-inworld-voice-cloning.json", "title": "Gradium Voice Cloning and Voice Design vs Inworld Instant Voice Cloning", "url": "https://www.anchorterminal.com/compare/gradium-voice-cloning-vs-inworld-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/gradium-voice-cloning-vs-smallest-voice-clone.json", "title": "Gradium Voice Cloning and Voice Design vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/gradium-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/hume-voice-cloning-vs-inworld-voice-cloning.json", "title": "Hume Octave Voice Design and Cloning + MCP vs Inworld Instant Voice Cloning", "url": "https://www.anchorterminal.com/compare/hume-voice-cloning-vs-inworld-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/hume-voice-cloning-vs-smallest-voice-clone.json", "title": "Hume Octave Voice Design and Cloning + MCP vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/hume-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-minimax-voice-cloning.json", "title": "Inworld Instant Voice Cloning vs MiniMax Voice Clone and Voice Design", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-minimax-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-murf-voice-cloning.json", "title": "Inworld Instant Voice Cloning vs Murf Voice Cloning API", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-murf-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-playht-voice-cloning.json", "title": "Inworld Instant Voice Cloning vs PlayHT Voice Cloning API", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-playht-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-resemble-ai-voice-cloning.json", "title": "Inworld Instant Voice Cloning vs Resemble AI Voice Cloning API", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-resemble-ai-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-soniox-voice-cloning.json", "title": "Inworld Instant Voice Cloning vs Soniox Voice Cloning", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-soniox-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-speechify-voice-cloning.json", "title": "Inworld Instant Voice Cloning vs Speechify API Voice Cloning", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-speechify-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-ultravox-voice-cloning.json", "title": "Inworld Instant Voice Cloning vs Ultravox Voice Cloning", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-ultravox-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-voicestudio.json", "title": "Inworld Instant Voice Cloning vs VoiceStudio", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-voicestudio" }, { "json": "https://www.anchorterminal.com/compare/minimax-voice-cloning-vs-smallest-voice-clone.json", "title": "MiniMax Voice Clone and Voice Design vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/minimax-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/murf-voice-cloning-vs-smallest-voice-clone.json", "title": "Murf Voice Cloning API vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/murf-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/playht-voice-cloning-vs-smallest-voice-clone.json", "title": "PlayHT Voice Cloning API vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/playht-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/resemble-ai-voice-cloning-vs-smallest-voice-clone.json", "title": "Resemble AI Voice Cloning API vs Smallest.ai Instant Voice Clone", "url": "https://www.anchorterminal.com/compare/resemble-ai-voice-cloning-vs-smallest-voice-clone" }, { "json": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-soniox-voice-cloning.json", "title": "Smallest.ai Instant Voice Clone vs Soniox Voice Cloning", "url": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-soniox-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-speechify-voice-cloning.json", "title": "Smallest.ai Instant Voice Clone vs Speechify API Voice Cloning", "url": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-speechify-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-ultravox-voice-cloning.json", "title": "Smallest.ai Instant Voice Clone vs Ultravox Voice Cloning", "url": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-ultravox-voice-cloning" }, { "json": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-voicestudio.json", "title": "Smallest.ai Instant Voice Clone vs VoiceStudio", "url": "https://www.anchorterminal.com/compare/smallest-voice-clone-vs-voicestudio" } ], "panel": null, "scores": [ { "by": 10, "edge": "inworld-voice-cloning", "inworld-voice-cloning": 75, "key": "reliability", "name": "Reliability", "smallest-voice-clone": 65, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 6, "edge": "smallest-voice-clone", "inworld-voice-cloning": 64, "key": "schema", "name": "Schema \u0026 documentation", "smallest-voice-clone": 70, "weight": 13 }, { "by": 2, "edge": "inworld-voice-cloning", "inworld-voice-cloning": 64, "key": "ergonomics", "name": "Agent ergonomics", "smallest-voice-clone": 62, "weight": 13 }, { "by": 7, "edge": "inworld-voice-cloning", "inworld-voice-cloning": 55, "key": "security", "name": "Security \u0026 auth", "smallest-voice-clone": 48, "weight": 14 }, { "by": 20, "edge": "inworld-voice-cloning", "inworld-voice-cloning": 40, "key": "payments", "name": "Payments \u0026 pricing", "smallest-voice-clone": 20, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 4, "edge": "smallest-voice-clone", "inworld-voice-cloning": 68, "key": "maintenance", "name": "Maintenance \u0026 community", "smallest-voice-clone": 72, "weight": 7 }, { "by": 9, "edge": "smallest-voice-clone", "inworld-voice-cloning": 63, "key": "transparency", "name": "Transparency \u0026 trust", "smallest-voice-clone": 72, "weight": 7 } ], "summary": "Inworld Instant Voice Cloning scores 61.9 (C) on agent readiness against Smallest.ai Instant Voice Clone's 58 (C), and leads in 4 of 7 scored categories. Smallest.ai Instant Voice Clone leads on schema \u0026 documentation and transparency \u0026 trust. Both do voice cloning. Inworld Instant Voice Cloning is cheaper for voice cloning, $15 against $17.50 per 1M characters.", "tasks": [ { "a": "$0.13 to $0.22", "b": "$0.16 to $0.18", "cheaper": "inworld-voice-cloning", "task": "Narrate a 9,000-character script", "what": "about 1,500 words" } ], "tutorials": [], "verdicts": { "inworld-voice-cloning": "One JSON call returns a usable voice ID from 3 to 30 seconds of audio, with no charge per clone and 100 custom voices on the free plan, behind keys that are read-only until write access is switched on. The API has no consent field, and Zero Data Retention excludes cloning samples.", "smallest-voice-clone": "One multipart POST clones a voice from 5 to 15 seconds of audio and returns sample clips, with dated deprecation notices and current changelog entries. The endpoint still defaults to a model whose clones stop working on 30 November 2026, there's no consent field or clone price, and the status feed shows frequent short API outages." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone", "json": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone.min.md" }, "markdown": "Inworld Instant Voice Cloning scores 61.9 (C) on agent readiness against Smallest.ai Instant Voice Clone's 58 (C), and leads in 4 of 7 scored categories. Smallest.ai Instant Voice Clone leads on schema \u0026 documentation and transparency \u0026 trust. Both do voice cloning. Inworld Instant Voice Cloning is cheaper for voice cloning, $15 against $17.50 per 1M characters.\n\n- Inworld Instant Voice Cloning: grade C, 61.9/100, rank #585 of 1486. Markdown https://www.anchorterminal.com/tools/inworld-voice-cloning.md · JSON https://www.anchorterminal.com/api/v1/tools/inworld-voice-cloning.json\n- Smallest.ai Instant Voice Clone: grade C, 58/100, rank #768 of 1486. Markdown https://www.anchorterminal.com/tools/smallest-voice-clone.md · JSON https://www.anchorterminal.com/api/v1/tools/smallest-voice-clone.json\n- Best voice cloning and custom voice APIs for AI agents: https://www.anchorterminal.com/best/voice-cloning/index.md\n- All 133 cloning comparisons: https://www.anchorterminal.com/compare/voice-cloning/index.md\n\n## Which one, for what\n\n### Inworld Instant Voice Cloning (C)\n\nGood for: Teams already using Inworld TTS-2 that want clones from a short clip through one call, the CLI or MCP.\n\nAhead on:\n- Reliability, 75 against 65\n- Security \u0026 auth, 55 against 48\n- Payments \u0026 pricing, 40 against 20\n\nAlso in its favour:\n- Cheaper for voice cloning, $15 against $17.50 per 1M characters\n- Runs on your own machine\n- Free to start without a card\n\nWatch for: No consent, verification or watermark field in the clone API. Only the Portal flow asks the user to confirm rights to the voice\n\n### Smallest.ai Instant Voice Clone (C)\n\nGood for: Teams already on Smallest's Lightning TTS or voice agents who want a clone from a short clip in one call.\n\nAhead on:\n- Schema \u0026 documentation, 70 against 64\n- Transparency \u0026 trust, 72 against 63\n\nWatch for: The endpoint defaults to `lightning-v3.1`, whose clones stop working on 30 November 2026\n\n\n## Why the edge\n\n### Payments \u0026 pricing: Inworld Instant Voice Cloning +20\n\n- Inworld Instant Voice Cloning (40): No x402, MPP or L402 (0). The pricing page, unread on 9 October and read on 6 November, publishes per-character rates for speech from a clone, $25 per million characters on TTS-2 and $15 on TTS-2 Flash on the free plan, and no charge for creating a clone (20, was 10). The On-Demand plan is free with 100 custom voices and instant cloning, and no card is asked for (20). `inworld login` opens a browser and signup is a human flow. The CLI mints keys only after that (0). 0+20+20+0 = 40.\n- Smallest.ai Instant Voice Clone (20): No x402, MPP or L402 (0). Per-character TTS prices are public, about $0.175 per 10,000 characters on Lightning v3.1, but no price per clone is published and the models pricing table marks voice cloning No on pay as you go, against the docs (10). The agents pricing page states $10 in free credits, and whether a card is needed wasn't established (10 of 20). A person signs up in a browser and creates the key in the dashboard (0). 0+10+10+0 = 20.\n\n### Reliability: Inworld Instant Voice Cloning +10\n\n- Inworld Instant Voice Cloning (75): Graded on the REST API, the surface an agent would call. Status page at status.inworld.ai, drawn from GitHub issues, with five components and none for cloning (20). Read through the GitHub API on 6 November, the 90 days from 8 August hold two incidents, 29 minutes of elevated TTS latency on 25 August and 26 minutes of elevated TTS 2.1 errors from a network fault at one GPU site on 28 October, both minor (20). Cloning limits are published per plan, 2 to 20 requests a minute (15). A 429 is documented with exponential backoff and jitter code, and since the 9 October check the rate-limits page says limits over a minute can carry `Retry-After`. No idempotency key or safe-retry guidance for clone creation (10 of 15, was 9). The pricing page, now read, names an SLA on Enterprise only with no terms or figure, as on inworld-tts (0). Instant cloning carries no Preview or Beta mark (10). 20+20+15+10+0+10 = 75.\n- Smallest.ai Instant Voice Clone (65): Graded on the hosted cloning API with the hosted lines. status.smallest.ai is the vendor's own status page with components per region and a dated incident feed (20). The feed, read on 6 November, has dozens of automated outage alerts on the API components in the 90 days from 8 August, most a few minutes long, and a cluster across every API region from 13 to 17 September. The 60-day uptime bars read 99.790 per cent for API USA and 99.849 per cent for API Global. No single outage of an hour was found, but repeated wide outages read as one major episode (10). Rate limits are published for TTS (one concurrent request, 100 a minute on pay as you go), while the per-organisation clone limit has no number (10 of 15). The limits page says to handle 429 gracefully and the clone errors say to retry a timeout, with no Retry-After, backoff figures or idempotency key (5 of 15). The pricing table lists an Enterprise SLA of 99.99 per cent (10). Instant cloning carries no beta label (10). 20+10+10+5+10+10 = 65.\n\n### Transparency \u0026 trust: Smallest.ai Instant Voice Clone +9\n\n- Inworld Instant Voice Cloning (63): Closed service with clear terms naming Theai, Inc. dba Inworld AI, read on 6 November (unread on 9 October because of the Content-Signal line), and MIT client packages on npm (15 of 30, was 8). The Zero Data Retention page is specific that cloning samples are retained to build the voice, but gives no period, and the Terms' no-training clause and the Privacy Notice's training use sit side by side without a reconciling sentence, as on inworld-tts (14 of 30). Dated notices in the docs, `inworld-tts-1` discontinued on 15 June 2026 and the 30-second clone limit from 15 August, with release stages defined and no written notice period (12 of 20). US by default with isolated EU and India regions on Enterprise. No sub-processor list was found in the docs (10 of 20). 15+14+12+10 = 51.\n- Smallest.ai Instant Voice Clone (72): Closed service with clear terms naming Smallest, Inc. under California law, effective 21 October 2026 (15 of 30). The Terms rule out training on customer content, the Privacy Policy (18 September 2026) gives retention criteria but no periods, and the Zero Data Retention page is specific about Enterprise options, with nothing on how long cloning samples are kept (16 of 30). A deprecation page with dated statuses (deprecated, rejects, removed, scheduled, retiring) and migration targets (16 of 20). Two regions named with locations. No sub-processor list was found and a DPA page exists unread (10 of 20). 15+16+16+10 = 57.\n\n### Security \u0026 auth: Inworld Instant Voice Cloning +7\n\n- Inworld Instant Voice Cloning (55): Graded for voice cloning as the other listings in this category were, with consent and misuse controls in place of the read-only line and training and retention of voice data in place of the prompt-injection line. Revocable workspace keys that are read-only for the Voice API until a write toggle is set, Realtime-only keys and single-use tokens, sent in a header (25 of 30). The API has no consent or verification field and no watermark was found. Only the Portal asks the user to confirm rights, and the Terms (11 June 2025), now read, have no clause on cloned voices. The write toggle keeps a default key from cloning (6 of 20). The Terms say Inworld won't train generally available models on non-public Materials except feedback and trust and safety content, while the Privacy Notice lists training among its uses. Zero Data Retention excludes cloning samples and no retention period for them is published (7 of 15, was 4). Usage is attributed per key in the dashboard and an experimental usage records endpoint exists from the Builder plan. No audit log found (7 of 15). GDPR and SOC 2 Type II are stated on every plan on the pricing page, and the security page links a vulnerability report form. No security.txt (404 per the 30 October inworld-tts check) and no bug bounty found (10 of 20, was 8). 25+6+7+7+10 = 55.\n- Smallest.ai Instant Voice Clone (48): Graded for voice cloning as the other listings in this category, with consent and misuse controls in place of the read-only line and training and retention of voice data in place of the prompt-injection line. Plain bearer keys, shown once, revocable, with rotation guidance and no scopes. Short-lived access tokens are refused on the cloning endpoint (20 of 30). No consent or verification field. The Terms let Smallest demand proof that the speaker authorised a clone and remove voices without it, and the prohibited use policy bars unauthorised impersonation. No watermark found (6 of 20). The Terms say Smallest won't use User Content or Input to train its services. Zero retention and retention windows are Enterprise options, and no retention period for samples is published (9 of 15). A usage dashboard, with no audit log found (5 of 15). A valid security.txt naming security@smallest.ai and a HIPAA business associate agreement page. The trust centre didn't answer through our proxy, so no certification was confirmed first-hand, and no bug bounty was found (8 of 20). 20+6+9+5+8 = 48.\n\n### Schema \u0026 documentation: Smallest.ai Instant Voice Clone +6\n\n- Inworld Instant Voice Cloning (64): No OpenAPI file is linked from the docs or `llms.txt`, re-read on 6 November. The MCP server has typed inputs on all 40 tools, which earns part of the line (10 of 25). `llms.txt`, `llms-full.txt` and Markdown twins (10). The guides say when to use instant cloning, Professional Voice Cloning or Voice Design, and the reference warns which fields are ignored (15 of 20). Required fields and base64 audio are typed, and a new `languageCode` string is validated against the catalogue with `INVALID_ARGUMENT`, while size and length limits sit in prose and the MCP tool still states different ones (10 of 15). Examples in curl, Python, JavaScript and the CLI, with one error response shown and no error list for the Voice API (9 of 15). A `/v1/` path and dated TTS release notes, newest 11 September, with no changelog for the Voice API itself (10 of 15). 10+10+15+10+9+10 = 64.\n- Smallest.ai Instant Voice Clone (70): The API reference pages are generated with typed fields, enums and error schemas, but no OpenAPI file was found linked from the docs or llms.txt (5 of 25). llms.txt and a Markdown copy of every page (10). The guide says when to use the Pro pool, how to check `modelIds` before synthesis and why a mismatched clone returns empty audio, while the reference still names the retiring default (14 of 20). `model` and `language` are enums validated by the server, with required `displayName` and `file`, a 5 MB limit and MIME types listed, and `tags` as a comma-separated string (12 of 15). Examples in curl, Python and Node.js and a table of seven error cases with causes (14 of 15). Paths under `/v1`, a deprecation page with dated statuses and a models changelog with entries on 21, 24, 26, 28 and 29 October 2026 (15). 5+10+14+12+14+15 = 70.\n\n## Score by category\n\n| Category | Weight | Inworld Instant Voice Cloning | Smallest.ai Instant Voice Clone | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 75 | 65 | Inworld Instant Voice Cloning +10 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 64 | 70 | Smallest.ai Instant Voice Clone +6 |\n| Agent ergonomics | 13% (16.2 this run) | 64 | 62 | Inworld Instant Voice Cloning +2 |\n| Security \u0026 auth | 14% (17.5 this run) | 55 | 48 | Inworld Instant Voice Cloning +7 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 20 | Inworld Instant Voice Cloning +20 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 68 | 72 | Smallest.ai Instant Voice Clone +4 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 63 | 72 | Smallest.ai Instant Voice Clone +9 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **61.9 · C** | **58 · C** | |\n\n## Facts side by side\n\n| Fact | Inworld Instant Voice Cloning | Smallest.ai Instant Voice Clone |\n| --- | --- | --- |\n| Kind | Model API | Model API |\n| Vendor | Inworld AI | Smallest, Inc. |\n| Hosted endpoint | `https://api.inworld.ai` | `https://api.smallest.ai/waves/v1/voice-cloning` |\n| Transports | HTTP, stdio, Streamable HTTP | HTTP |\n| Auth | API key | API key |\n| Pricing | Freemium | Pay per use |\n| Price for voice cloning | $15 per 1M characters | $17.50 per 1M characters |\n| x402 | no | no |\n| Licence | Proprietary service under Inworld's Terms of Service. The `@inworld/cli` and `@inworld/tts` npm packages and the examples repository are MIT | Proprietary service under Smallest's Terms of Service. The `smallestai` Python SDK is on PyPI |\n| Tools exposed | 40 | none |\n| Read-only variant documented | yes | no |\n| llms.txt | yes | yes |\n| Last release | 2026-10-29 | 2026-10-29 |\n| Terms last updated | 2025-06-11 | no date given |\n| Privacy policy last updated | 2026-01-18 | no date given |\n| Customer content may train models | not found in the text | not found in the text |\n| Terms restrict automated access | not found in the text | not found in the text |\n| Terms restrict benchmarking | not found in the text | not found in the text |\n| Terms or service can change without notice | not found in the text | yes |\n| Arbitration or class-action waiver | not found in the text | yes |\n| Popularity | 3.6k npm/wk | none |\n\n## What the same task costs\n\n| Task | Inworld Instant Voice Cloning | Smallest.ai Instant Voice Clone |\n| --- | --- | --- |\n| Narrate a 9,000-character script | $0.13 to $0.22 | $0.16 to $0.18 |\n\n## Verdicts\n\n**Inworld Instant Voice Cloning.** One JSON call returns a usable voice ID from 3 to 30 seconds of audio, with no charge per clone and 100 custom voices on the free plan, behind keys that are read-only until write access is switched on. The API has no consent field, and Zero Data Retention excludes cloning samples.\n\n**Smallest.ai Instant Voice Clone.** One multipart POST clones a voice from 5 to 15 seconds of audio and returns sample clips, with dated deprecation notices and current changelog entries. The endpoint still defaults to a model whose clones stop working on 30 November 2026, there's no consent field or clone price, and the status feed shows frequent short API outages.\n\n## Before you call either\n\n### Inworld Instant Voice Cloning\n\n1. Create the key with write access (`inworld workspace add-key --write`). A default key gets code 7, insufficient access level, on `voices:clone`\n2. Send the complete Base64 credential as `Authorization: Basic $INWORLD_API_KEY`. Don't encode it again\n3. Send one 10 to 30 second WAV or MP3 clip as base64 in `voiceSamples[].audioData`. Audio past 30 seconds is cut\n4. Don't blind-retry a clone. There's no idempotency key, so list voices with `filter=source=\"IVC\"` first, and back off with jitter on 429\n5. Set `gender`, `ageGroup` and `categories` with UpdateVoice afterwards. The clone call ignores them without an error\n6. The response echoes up to 15 seconds of processed audio as base64 in `audioSamplesValidated`. Drop it before passing the result to a model\n\n### Smallest.ai Instant Voice Clone\n\n1. Always pass `model=lightning-v3.1-pro`. The default `lightning-v3.1` clones stop working on 30 November 2026\n2. Use the returned `voiceId` with the matching TTS model and check `modelIds` from `GET /waves/v1/voice-cloning` if a TTS call returns a tiny WAV\n3. Before retrying a `voice_clone_timeout`, list clones by `displayName` so a retry doesn't create a duplicate\n4. Send the server API key, not an access token. The cloning endpoint refuses short-lived tokens\n5. Keep TTS calls from a clone to one at a time on the self-serve plan and back off on 429\n\n## Questions\n\n### Which is better for AI agents, Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone?\n\nInworld Instant Voice Cloning scores 61.9 (C) on agent readiness against Smallest.ai Instant Voice Clone's 58 (C), and leads in 4 of 7 scored categories. Smallest.ai Instant Voice Clone leads on schema \u0026 documentation and transparency \u0026 trust.\n\n### Which is cheaper for voice cloning, Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone?\n\nInworld Instant Voice Cloning, at $15 per 1M characters against $17.50 per 1M characters for Smallest.ai Instant Voice Clone. These are the vendors' published prices for the job.\n\n### Do Inworld Instant Voice Cloning and Smallest.ai Instant Voice Clone need an API key?\n\nBoth need an API key.\n\n### Can an agent call Inworld Instant Voice Cloning and Smallest.ai Instant Voice Clone without installing anything?\n\nYes. Inworld Instant Voice Cloning has a hosted endpoint at https://api.inworld.ai and Smallest.ai Instant Voice Clone at https://api.smallest.ai/waves/v1/voice-cloning.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone.json, and with the fewest tokens: https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"inworld-voice-cloning\", \"b\": \"smallest-voice-clone\"}`. From a terminal: `anchor compare inworld-voice-cloning smallest-voice-clone`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/inworld-voice-cloning.json and https://www.anchorterminal.com/api/v1/tools/smallest-voice-clone.json\n\n## Other comparisons with Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone\n\n- [Cartesia Voice Cloning API + MCP vs Inworld Instant Voice Cloning](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-inworld-voice-cloning.md)\n- [Cartesia Voice Cloning API + MCP vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-smallest-voice-clone.md)\n- [ElevenLabs Voice Cloning and Voice Design API vs Inworld Instant Voice Cloning](https://www.anchorterminal.com/compare/elevenlabs-voice-cloning-vs-inworld-voice-cloning.md)\n- [ElevenLabs Voice Cloning and Voice Design API vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/elevenlabs-voice-cloning-vs-smallest-voice-clone.md)\n- [Fish Audio Voice Cloning API vs Inworld Instant Voice Cloning](https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-inworld-voice-cloning.md)\n- [Fish Audio Voice Cloning API vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-smallest-voice-clone.md)\n- [Gradium Voice Cloning and Voice Design vs Inworld Instant Voice Cloning](https://www.anchorterminal.com/compare/gradium-voice-cloning-vs-inworld-voice-cloning.md)\n- [Gradium Voice Cloning and Voice Design vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/gradium-voice-cloning-vs-smallest-voice-clone.md)\n- [Hume Octave Voice Design and Cloning + MCP vs Inworld Instant Voice Cloning](https://www.anchorterminal.com/compare/hume-voice-cloning-vs-inworld-voice-cloning.md)\n- [Hume Octave Voice Design and Cloning + MCP vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/hume-voice-cloning-vs-smallest-voice-clone.md)\n- [Inworld Instant Voice Cloning vs MiniMax Voice Clone and Voice Design](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-minimax-voice-cloning.md)\n- [Inworld Instant Voice Cloning vs Murf Voice Cloning API](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-murf-voice-cloning.md)\n- [Inworld Instant Voice Cloning vs PlayHT Voice Cloning API](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-playht-voice-cloning.md)\n- [Inworld Instant Voice Cloning vs Resemble AI Voice Cloning API](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-resemble-ai-voice-cloning.md)\n- [Inworld Instant Voice Cloning vs Soniox Voice Cloning](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-soniox-voice-cloning.md)\n- [Inworld Instant Voice Cloning vs Speechify API Voice Cloning](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-speechify-voice-cloning.md)\n- [Inworld Instant Voice Cloning vs Ultravox Voice Cloning](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-ultravox-voice-cloning.md)\n- [Inworld Instant Voice Cloning vs VoiceStudio](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-voicestudio.md)\n- [MiniMax Voice Clone and Voice Design vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/minimax-voice-cloning-vs-smallest-voice-clone.md)\n- [Murf Voice Cloning API vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/murf-voice-cloning-vs-smallest-voice-clone.md)\n- [PlayHT Voice Cloning API vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/playht-voice-cloning-vs-smallest-voice-clone.md)\n- [Resemble AI Voice Cloning API vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/resemble-ai-voice-cloning-vs-smallest-voice-clone.md)\n- [Smallest.ai Instant Voice Clone vs Soniox Voice Cloning](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-soniox-voice-cloning.md)\n- [Smallest.ai Instant Voice Clone vs Speechify API Voice Cloning](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-speechify-voice-cloning.md)\n- [Smallest.ai Instant Voice Clone vs Ultravox Voice Cloning](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-ultravox-voice-cloning.md)\n- [Smallest.ai Instant Voice Clone vs VoiceStudio](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-voicestudio.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "attributionRequired": true, "credit": "CC BY 4.0, credit Anchor Terminal and link the page or API address you took it from (https://www.anchorterminal.com/terms/#data)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-11-07", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.7", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run", "terms": "https://www.anchorterminal.com/terms/#data" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Inworld Instant Voice Cloning vs Smallest.ai Instant Voice Clone", "url": "" } ], "description": "Inworld Instant Voice Cloning scores 61.9 (C) to Smallest.ai Instant Voice Clone's 58 (C) for voice cloning. Inworld Instant Voice Cloning is cheaper for voice cloning, $15 against $17.50 per 1M characters. Prices, MCP, x402, uptime and agent notes side by side.", "facts": [ "Inworld Instant Voice Cloning C 61.9", "Smallest.ai Instant Voice Clone C 58", "scores" ], "h1": "Inworld Instant Voice Cloning vs Smallest.ai Instant Voice Clone", "image": "https://www.anchorterminal.com/assets/og/default.png", "path": "/compare/inworld-voice-cloning-vs-smallest-voice-clone", "published": "2026-10-01", "section": "tools", "title": "Inworld Instant Voice Cloning vs Smallest.ai Instant Voice Clone", "toc": null, "updated": "2026-11-07", "url": "https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone" }, "tokens": { "markdown": 5600, "slim": 3080 }, "version": 1 }