# Cartesia Voice Cloning API + MCP vs Smallest.ai Instant Voice Clone

> Cartesia Voice Cloning and Smallest.ai Instant Voice Clone score within a point of each other for voice cloning, 58.3 and 58 out of 100. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-smallest-voice-clone
- Markdown: https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-smallest-voice-clone.md (~5,800 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Cartesia Voice Cloning API + MCP and Smallest.ai Instant Voice Clone score within a point of each other on agent readiness, 58.3 (C) and 58 (C). Smallest.ai Instant Voice Clone leads on security & auth and payments & pricing. Both do voice cloning.

- Cartesia Voice Cloning API + MCP: grade C, 58.3/100, rank #751 of 1486. Markdown https://www.anchorterminal.com/tools/cartesia-voice-cloning.md · JSON https://www.anchorterminal.com/api/v1/tools/cartesia-voice-cloning.json
- 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
- Best voice cloning and custom voice APIs for AI agents: https://www.anchorterminal.com/best/voice-cloning/index.md
- All 133 cloning comparisons: https://www.anchorterminal.com/compare/voice-cloning/index.md

## Which one, for what

### Cartesia Voice Cloning API + MCP (C)

Good for: Teams that want cheap instant clones and fast streaming TTS in the same account, especially voice agents.

Ahead on:
- Reliability, 73 against 65
- Schema & documentation, 85 against 70
- Maintenance & community, 84 against 72

Also in its favour:
- Runs on your own machine

Watch for: No consent or speaker verification in the clone API

### Smallest.ai Instant Voice Clone (C)

Good for: Teams already on Smallest's Lightning TTS or voice agents who want a clone from a short clip in one call.

Ahead on:
- Security & auth, 48 against 42
- Payments & pricing, 20 against 10

Also in its favour:
- No incidents deducted, where Cartesia Voice Cloning API + MCP loses 3 points for them

Watch for: The endpoint defaults to `lightning-v3.1`, whose clones stop working on 30 November 2026


## Why the edge

### Schema & documentation: Cartesia Voice Cloning API + MCP +15

- Cartesia Voice Cloning API + MCP (85): OpenAPI files for the latest and each dated API version are listed in llms.txt (25). llms.txt and Markdown pages served (10). The cloning guides say when to use an instant clone and when to move to a Pro clone (14 of 20). Clone inputs are typed, with a language enum, an access enum, a 32 character tagline limit and accepted file formats, and `clip`, `name` and `language` required (13 of 15). Examples in curl and both SDKs, but the clone endpoint's OpenAPI lists only a 200 response, with errors on a general API errors page and SDK exception classes (8 of 15). Dated `Cartesia-Version` header (2026-08-14 the only accepted value on the clone endpoint) and a monthly changelog (15). Re-read on 4 November.
- 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.

### Maintenance & community: Cartesia Voice Cloning API + MCP +12

- Cartesia Voice Cloning API + MCP (84): Read as a model, on the lines cartesia-tts, cartesia-ink-stt and the other hosted speech models use (recency 30, dated releases 10, deprecation notice 10, support 15, issues 10, SDKs 15, health 10); the 1 October check used the tool lines. `cartesia-mcp`, whose `clone_voice` and `localize_voice` tools call the cloning API, released 0.28.1 on 30 October 2026 after 0.26.1 (8 October), 0.27.0 (20 October), 0.27.1 (23 October) and 0.28.0 (27 October) (30). From 6 August the Python and TypeScript SDKs released 4.0.0, 4.0.1, 4.1.0 and 4.2.0 (14 August to 2 September) and the MCP server more than ten releases (10). Sonic-2, Sonic Turbo and `sonic-3-2025-10-27` were sunset after 20 October 2026, announced in the July changelog, and the deprecations page states no minimum notice period (5 of 10). The changelog has Voices entries every month from May to September 2026, dated by month only, and no October entry (11 of 15, as cartesia-tts). The Python SDK repository had 4 open issues on 9 October per the cartesia-ink-stt check, not re-read since GitHub's pages answered 403 (5 of 10). Official `cartesia` and `@cartesia/cartesia-js` SDKs at 4.2.0 (2 September 2026), generated for API version 2026-08-14 (15). CI (test.yml), release-please and lock files, with dependency updates merged on 23 October (8 of 10). 30+10+5+11+5+15+8 = 84.
- Smallest.ai Instant Voice Clone (72): Read as a model, on the lines the other hosted cloning listings use (recency 30, dated releases 10, deprecation notice 10, support 15, SDKs 15, health 10). The models changelog has entries dated 29 October 2026 (30). Entries on 21, 24, 26, 28 and 29 October and in September (10). The deprecation page dates each retirement, such as `lightning-v3.1` and its clones on 30 November 2026 with steps to migrate, though when the clone retirement was first announced wasn't found (7 of 10). Public changelog, support@smallest.ai and a Discord server, with no evidence read of how they answer (10 of 15). `smallestai` on PyPI released 5.12.3 to 5.14.0 between 1 and 7 October 2026, from a repository under fern-demo. The npm package is stale (10 of 15). Package repositories weren't cloned (5 of 10). 30+10+7+10+10+5 = 72.

### Payments & pricing: Smallest.ai Instant Voice Clone +10

- Cartesia Voice Cloning API + MCP (10): No x402, MPP or L402 (0). Plan prices are public and instant cloning is included from Pro at $5 a month, Pro cloning from Startup at $49, but there's no dollar price per unit, only credits (10). The Free plan has no cloning, re-read on 4 November (0). Signup is a human browser flow (0). 0+10+0+0 = 10.
- 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.

### Reliability: Cartesia Voice Cloning API + MCP +8

- Cartesia Voice Cloning API + MCP (73): incident.io status page at status.cartesia.ai with a Voice Cloning component and a dated history (20). feed.rss, read on 4 November, lists these items touching Voice Cloning from 6 August to 4 November 2026. 7 August "Agents Telephony failing in the US" lists every component in the feed, but its incident page names only Voice Agents, as a partial outage. 4 September "Intermittent issues with voice cloning in APAC" (about 21 hours across 3 and 4 September per the 1 October reading), one region. 7 October "Degraded API Performance in US Regions", US only. 23 October "Elevated latency for instant voice cloning", latency. Each is partial and minor under this run's incident rule, and the 1 August API-wide major has left the window. Minor incidents only (20; was 10), as cartesia-tts and cartesia-ink-stt on the same page. Concurrency limits per plan are published, 2 to 15 TTS requests (15). A 429 is documented when the limit is hit, with no Retry-After or backoff guidance in the docs, but the official SDK README says it retries 429 and 5xx twice with exponential backoff, and there is no idempotency key or safe-retry guidance for clone creation (8). No SLA published (0). Instant cloning is generally available (10). 20+20+15+8+0+10 = 73.
- 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.

### Security & auth: Smallest.ai Instant Voice Clone +6

- Cartesia Voice Cloning API + MCP (42): Graded on the model lines with the voice-cloning substitutions this run uses (consent and misuse controls in place of the read-only line, training and retention of voice data in place of the prompt-injection line), on the same evidence and values as cartesia-tts and cartesia-ink-stt where it is shared. Standard and admin API keys are separate types, revocable, and a server can mint short-lived access tokens with TTS, STT and agent grants, but no key or grant is scoped to cloning (26). Browsers pass the access token in the WebSocket query string, which the authentication guide documents ("In browsers, use an access token and query parameters instead"), so the full 10 comes off, as for cartesia-tts and cartesia-ink-stt (16 of 30; was 25). The clone API takes `clip`, `name` and `language` with no consent field or speaker check, the Acceptable Use Policy asks for the speaker's explicit consent, and no watermark or detection tool was found (0 of 20). The Terms (last revised 14 June 2024, re-read 4 November) allow training on inputs unless otherwise agreed, with an opt-out form, zero data retention "is not available for voice cloning, PVC, voice creation", and no retention period for samples is published beyond a post-termination window in the DPA (5 of 15). Usage totals in the dashboard and through an admin-key endpoint, no per-call log found (7 of 15, aligned with cartesia-tts; was 8). security.txt at www.cartesia.ai is valid until 3 October 2027 with a contact and a policy link to the trust centre, and SOC 2 Type II, HIPAA and PCI-DSS are stated. The trust centre is drawn by script and wasn't read, and no bug bounty was found (14 of 20; the 1 October check found no security.txt, 10). 16+0+5+7+14 = 42.
- 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.

## Score by category

| Category | Weight | Cartesia Voice Cloning API + MCP | Smallest.ai Instant Voice Clone | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 73 | 65 | Cartesia Voice Cloning API + MCP +8 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 85 | 70 | Cartesia Voice Cloning API + MCP +15 |
| Agent ergonomics | 13% (16.2 this run) | 65 | 62 | Cartesia Voice Cloning API + MCP +3 |
| Security & auth | 14% (17.5 this run) | 42 | 48 | Smallest.ai Instant Voice Clone +6 |
| Payments & pricing | 10% (12.5 this run) | 10 | 20 | Smallest.ai Instant Voice Clone +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 84 | 72 | Cartesia Voice Cloning API + MCP +12 |
| Transparency & trust | 7% (8.8 this run) | 73 | 72 | Cartesia Voice Cloning API + MCP +1 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **58.3 · C** | **58 · C** | |

## Facts side by side

| Fact | Cartesia Voice Cloning API + MCP | Smallest.ai Instant Voice Clone |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Cartesia | Smallest, Inc. |
| Hosted endpoint | `https://api.cartesia.ai` | `https://api.smallest.ai/waves/v1/voice-cloning` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Pay per use |
| Price for voice cloning | not published | $17.50 per 1M characters |
| x402 | no | no |
| Licence | Apache-2.0 (SDKs) | Proprietary service under Smallest's Terms of Service. The `smallestai` Python SDK is on PyPI |
| Tools exposed | 19 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-30 | 2026-10-29 |
| Terms last updated | 2024-06-14 | no date given |
| Privacy policy last updated | 2024-06-14 | no date given |
| Customer content may train models | yes, with an opt-out | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | yes | yes |
| Popularity | 133 stars, 166k npm/wk, 177k PyPI/wk | none |
| Agent reviews | 2.5/5 (2) | none |

## How the scores have moved

### Cartesia Voice Cloning API + MCP

- -1.4 on 4 November 2026: new evidence, correction, negative event, time
- +0.2 on 27 October 2026: checklist
- -0.3 on 8 October 2026: checklist

### Smallest.ai Instant Voice Clone

No score change since it was listed.

## Verdicts

**Cartesia Voice Cloning API + MCP.** Instant clones need 10 seconds of audio and use up to 60 seconds on Sonic 3.6, and the official MCP server exposes cloning with annotated tools. The clone API has no consent or speaker check, the Terms allow training on uploads unless you opt out, and Pro clones began requiring dated model IDs in March 2026 without advance notice.

**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.

## Before you call either

### Cartesia Voice Cloning API + MCP

1. Send `Cartesia-Version` on every call. The clone endpoint lists it as a required header
2. Pass the speaker's recorded `language`. A clone is built from one language, add others with the accents API
3. Keep IVC uploads under 16 MB
4. Don't blind-retry `POST /voices/clone`. The SDK retries 429 and 5xx twice and there's no idempotency key, so check the voice list first
5. Call a Pro clone with a model from its `fine_tunes.public_model_id`, such as `sonic-3.6-2026-08-27`, not an undated alias

### Smallest.ai Instant Voice Clone

1. Always pass `model=lightning-v3.1-pro`. The default `lightning-v3.1` clones stop working on 30 November 2026
2. 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
3. Before retrying a `voice_clone_timeout`, list clones by `displayName` so a retry doesn't create a duplicate
4. Send the server API key, not an access token. The cloning endpoint refuses short-lived tokens
5. Keep TTS calls from a clone to one at a time on the self-serve plan and back off on 429

## Tutorials

- [Create a private voice clone with Cartesia](https://www.anchorterminal.com/tutorials/cartesia-voice-cloning/), for Cartesia Voice Cloning API + MCP

## Questions

### Which is better for AI agents, Cartesia Voice Cloning API + MCP or Smallest.ai Instant Voice Clone?

Cartesia Voice Cloning API + MCP and Smallest.ai Instant Voice Clone score within a point of each other on agent readiness, 58.3 (C) and 58 (C). Smallest.ai Instant Voice Clone leads on security & auth and payments & pricing.

### Do Cartesia Voice Cloning API + MCP and Smallest.ai Instant Voice Clone need an API key?

Cartesia Voice Cloning API + MCP takes an API key or an OAuth sign-in. Smallest.ai Instant Voice Clone needs an API key.

### Can an agent call Cartesia Voice Cloning API + MCP and Smallest.ai Instant Voice Clone without installing anything?

Yes. Cartesia Voice Cloning API + MCP has a hosted endpoint at https://api.cartesia.ai and Smallest.ai Instant Voice Clone at https://api.smallest.ai/waves/v1/voice-cloning.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-smallest-voice-clone.json, and with the fewest tokens: https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-smallest-voice-clone.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "cartesia-voice-cloning", "b": "smallest-voice-clone"}`. From a terminal: `anchor compare cartesia-voice-cloning smallest-voice-clone`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/cartesia-voice-cloning.json and https://www.anchorterminal.com/api/v1/tools/smallest-voice-clone.json

## Other comparisons with Cartesia Voice Cloning API + MCP or Smallest.ai Instant Voice Clone

- [Cartesia Voice Cloning API + MCP vs ElevenLabs Voice Cloning and Voice Design API](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-elevenlabs-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Fish Audio Voice Cloning API](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-fish-audio-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Gradium Voice Cloning and Voice Design](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-gradium-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Hume Octave Voice Design and Cloning + MCP](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-hume-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Inworld Instant Voice Cloning](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-inworld-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs MiniMax Voice Clone and Voice Design](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-minimax-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Murf Voice Cloning API](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-murf-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs PlayHT Voice Cloning API](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-playht-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Resemble AI Voice Cloning API](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-resemble-ai-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Soniox Voice Cloning](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-soniox-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Speechify API Voice Cloning](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-speechify-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs Ultravox Voice Cloning](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-ultravox-voice-cloning.md)
- [Cartesia Voice Cloning API + MCP vs VoiceStudio](https://www.anchorterminal.com/compare/cartesia-voice-cloning-vs-voicestudio.md)
- [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)
- [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)
- [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)
- [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)
- [Inworld Instant Voice Cloning vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone.md)
- [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)
- [Murf Voice Cloning API vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/murf-voice-cloning-vs-smallest-voice-clone.md)
- [PlayHT Voice Cloning API vs Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/compare/playht-voice-cloning-vs-smallest-voice-clone.md)
- [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)
- [Smallest.ai Instant Voice Clone vs Soniox Voice Cloning](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-soniox-voice-cloning.md)
- [Smallest.ai Instant Voice Clone vs Speechify API Voice Cloning](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-speechify-voice-cloning.md)
- [Smallest.ai Instant Voice Clone vs Ultravox Voice Cloning](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-ultravox-voice-cloning.md)
- [Smallest.ai Instant Voice Clone vs VoiceStudio](https://www.anchorterminal.com/compare/smallest-voice-clone-vs-voicestudio.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp