# Inworld Instant Voice Cloning vs Smallest.ai Instant Voice Clone

> 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.

- Canonical: https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone
- Markdown: https://www.anchorterminal.com/compare/inworld-voice-cloning-vs-smallest-voice-clone.md (~5,600 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

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 & documentation and transparency & trust. Both do voice cloning. Inworld Instant Voice Cloning is cheaper for voice cloning, $15 against $17.50 per 1M characters.

- 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
- 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

### Inworld Instant Voice Cloning (C)

Good for: Teams already using Inworld TTS-2 that want clones from a short clip through one call, the CLI or MCP.

Ahead on:
- Reliability, 75 against 65
- Security & auth, 55 against 48
- Payments & pricing, 40 against 20

Also in its favour:
- Cheaper for voice cloning, $15 against $17.50 per 1M characters
- Runs on your own machine
- Free to start without a card

Watch for: No consent, verification or watermark field in the clone API. Only the Portal flow asks the user to confirm rights to the voice

### 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:
- Schema & documentation, 70 against 64
- Transparency & trust, 72 against 63

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


## Why the edge

### Payments & pricing: Inworld Instant Voice Cloning +20

- 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.
- 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: Inworld Instant Voice Cloning +10

- 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.
- 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.

### Transparency & trust: Smallest.ai Instant Voice Clone +9

- 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.
- 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.

### Security & auth: Inworld Instant Voice Cloning +7

- 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.
- 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.

### Schema & documentation: Smallest.ai Instant Voice Clone +6

- 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.
- 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.

## Score by category

| Category | Weight | Inworld Instant Voice Cloning | Smallest.ai Instant Voice Clone | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 75 | 65 | Inworld Instant Voice Cloning +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 64 | 70 | Smallest.ai Instant Voice Clone +6 |
| Agent ergonomics | 13% (16.2 this run) | 64 | 62 | Inworld Instant Voice Cloning +2 |
| Security & auth | 14% (17.5 this run) | 55 | 48 | Inworld Instant Voice Cloning +7 |
| Payments & pricing | 10% (12.5 this run) | 40 | 20 | Inworld Instant Voice Cloning +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 68 | 72 | Smallest.ai Instant Voice Clone +4 |
| Transparency & trust | 7% (8.8 this run) | 63 | 72 | Smallest.ai Instant Voice Clone +9 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **61.9 · C** | **58 · C** | |

## Facts side by side

| Fact | Inworld Instant Voice Cloning | Smallest.ai Instant Voice Clone |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Inworld AI | Smallest, Inc. |
| Hosted endpoint | `https://api.inworld.ai` | `https://api.smallest.ai/waves/v1/voice-cloning` |
| Transports | HTTP, stdio, Streamable HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| Price for voice cloning | $15 per 1M characters | $17.50 per 1M characters |
| x402 | no | no |
| 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 |
| Tools exposed | 40 | none |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| Last release | 2026-10-29 | 2026-10-29 |
| Terms last updated | 2025-06-11 | no date given |
| Privacy policy last updated | 2026-01-18 | no date given |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 3.6k npm/wk | none |

## What the same task costs

| Task | Inworld Instant Voice Cloning | Smallest.ai Instant Voice Clone |
| --- | --- | --- |
| Narrate a 9,000-character script | $0.13 to $0.22 | $0.16 to $0.18 |

## Verdicts

**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.

**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

### Inworld Instant Voice Cloning

1. Create the key with write access (`inworld workspace add-key --write`). A default key gets code 7, insufficient access level, on `voices:clone`
2. Send the complete Base64 credential as `Authorization: Basic $INWORLD_API_KEY`. Don't encode it again
3. Send one 10 to 30 second WAV or MP3 clip as base64 in `voiceSamples[].audioData`. Audio past 30 seconds is cut
4. 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
5. Set `gender`, `ageGroup` and `categories` with UpdateVoice afterwards. The clone call ignores them without an error
6. The response echoes up to 15 seconds of processed audio as base64 in `audioSamplesValidated`. Drop it before passing the result to a model

### 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

## Questions

### Which is better for AI agents, Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone?

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 & documentation and transparency & trust.

### Which is cheaper for voice cloning, Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone?

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.

### Do Inworld Instant Voice Cloning and Smallest.ai Instant Voice Clone need an API key?

Both need an API key.

### Can an agent call Inworld Instant Voice Cloning and Smallest.ai Instant Voice Clone without installing anything?

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.


## For agents

- 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
- 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`
- 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

## Other comparisons with Inworld Instant Voice Cloning or Smallest.ai Instant Voice Clone

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