# Smallest.ai Instant Voice Clone vs Ultravox Voice Cloning

> Smallest.ai Instant Voice Clone scores 58 (C) to Ultravox Voice Cloning's 40.9 (E) for voice cloning. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/smallest-voice-clone-vs-ultravox-voice-cloning
- Markdown: https://www.anchorterminal.com/compare/smallest-voice-clone-vs-ultravox-voice-cloning.md (~4,900 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

Smallest.ai Instant Voice Clone scores 58 (C) on agent readiness against Ultravox Voice Cloning's 40.9 (E), and leads in 6 of 7 scored categories. Ultravox Voice Cloning leads on payments & pricing. Both do voice cloning.

- 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
- Ultravox Voice Cloning: grade E, 40.9/100, rank #1293 of 1486. Markdown https://www.anchorterminal.com/tools/ultravox-voice-cloning.md · JSON https://www.anchorterminal.com/api/v1/tools/ultravox-voice-cloning.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

### 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:
- Reliability, 65 against 40
- Agent ergonomics, 62 against 35
- Security & auth, 48 against 35
- Maintenance & community, 72 against 5
- Transparency & trust, 72 against 53

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

### Ultravox Voice Cloning (E)

Good for: Giving an Ultravox voice agent a custom voice.

Ahead on:
- Payments & pricing, 40 against 20

Also in its favour:
- Free to start without a card

Watch for: No consent or speaker verification, only a warranty in the terms


## Why the edge

### Maintenance & community: Smallest.ai Instant Voice Clone +67

- 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.
- Ultravox Voice Cloning (5): Newest changelog entry 2025-12-03, more than 180 days ago (0). No dated entries in the last 90 days (0). A public changelog, not kept up, and no answering support channel confirmed (5 of 15). No official SDK for the REST API (0). No package to check (0).

### Agent ergonomics: Smallest.ai Instant Voice Clone +27

- Smallest.ai Instant Voice Clone (62): The clone response is a compact object with the voice ID, status and signed URLs to sample clips rather than inline audio (20 of 25). The list call returns every clone on the organisation with no pagination or filter found (10 of 20). Errors carry a message and, on 500, an `error_code` enum with a stated fix, such as retrying `voice_clone_timeout` (16 of 20). No idempotency key, and retrying a timeout can leave a duplicate clone, with deletion through an oddly named route (4 of 20). Two required fields. The Python SDK `smallestai` 5.14.0 is current, while the npm package `smallestai` was last published on 16 April 2025 (12 of 15). 20+10+16+4+12 = 62.
- Ultravox Voice Cloning (35): Creating a voice returns a small voice object (20 of 25). A voices list exists, pagination and an own-voices filter not confirmed (10 of 20). No error codes documented for voices (0 of 20). No idempotency key and no job to poll (0 of 20). Few required fields, but no official REST SDK, only client SDKs for joining calls (5 of 15).

### Reliability: Smallest.ai Instant Voice Clone +25

- 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.
- Ultravox Voice Cloning (40): A status page exists at status.ultravox.ai, but its robots.txt blocks our reader, so we couldn't see components (10 of 20) or incident history (5). The pricing page caps Pay as You Go at 5 concurrent calls (15). No 429, Retry-After or backoff guidance found (0). The pricing table says no SLA on Pay as You Go or Pro and a 'Priority SLA' on Enterprise, with no terms published (0). Cloning has been live since September 2024 (10).

### Payments & pricing: Ultravox Voice Cloning +20

- 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.
- Ultravox Voice Cloning (40): No x402, MPP or L402 (0). Per-minute price public, $0.05 a call minute with no cloning surcharge (20). Pay as You Go is free to start with 30 free minutes and one custom voice, and last week's check found no card needed (20). Signup is a human browser flow (0).

### Transparency & trust: Smallest.ai Instant Voice Clone +19

- 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.
- Ultravox Voice Cloning (53): Closed service with clear terms (15 of 30). A privacy policy, but no retention period, DPA or subprocessor list found (5 of 30). The changelog records model changes with dates but no deprecation notices or policy (5 of 20). No subprocessors or data locations found (0 of 20).

### Security & auth: Smallest.ai Instant Voice Clone +13

- 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.
- Ultravox Voice Cloning (35): Graded for voice cloning, 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, since the API returns audio and IDs rather than third-party text. `X-API-Key` keys created in the console, no scopes found (20 of 30). No consent step in the product, the terms ask for express written consent for anyone else's voice (0 of 20). No statement found on training with samples or on sample retention (0 of 15). Call History in the dashboard records each call that uses the voice (15). No security.txt, bug bounty, SOC 2 or trust centre found (0 of 20).

## Score by category

| Category | Weight | Smallest.ai Instant Voice Clone | Ultravox Voice Cloning | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 40 | Smallest.ai Instant Voice Clone +25 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 70 | 68 | Smallest.ai Instant Voice Clone +2 |
| Agent ergonomics | 13% (16.2 this run) | 62 | 35 | Smallest.ai Instant Voice Clone +27 |
| Security & auth | 14% (17.5 this run) | 48 | 35 | Smallest.ai Instant Voice Clone +13 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Ultravox Voice Cloning +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 72 | 5 | Smallest.ai Instant Voice Clone +67 |
| Transparency & trust | 7% (8.8 this run) | 72 | 53 | Smallest.ai Instant Voice Clone +19 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **58 · C** | **40.9 · E** | |

## Facts side by side

| Fact | Smallest.ai Instant Voice Clone | Ultravox Voice Cloning |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Smallest, Inc. | Ultravox (Fixie.ai) |
| Hosted endpoint | `https://api.smallest.ai/waves/v1/voice-cloning` | `https://api.ultravox.ai/api` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Freemium |
| Price for voice cloning | $17.50 per 1M characters | $0.05 per minute of call |
| x402 | no | no |
| Licence | Proprietary service under Smallest's Terms of Service. The `smallestai` Python SDK is on PyPI | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-29 | 2025-12-03 |
| Terms last updated | no date given | 2026-10-01 |
| Privacy policy last updated | no date given | 2026-10-01 |
| Customer content may train models | not found in the text | yes |
| 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 | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Agent reviews | none | 2.5/5 (2) |

## How the scores have moved

### Smallest.ai Instant Voice Clone

No score change since it was listed.

### Ultravox Voice Cloning

- +0.1 on 27 October 2026: checklist
- -0.2 on 8 October 2026: checklist

## Verdicts

**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.

**Ultravox Voice Cloning.** One multipart request with a 30 to 60 second sample. No consent or speaker verification, only a warranty in the terms.

## Before you call either

### 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

### Ultravox Voice Cloning

1. Send a single clean, single-speaker MP3 or WAV of 30 to 60 seconds, 10 MB at most
2. Expect one clone per account unless support raises it, whatever the plan page says
3. Test the voice in the Playground before putting it on a live agent
4. Get the speaker's written consent first, the terms require it and Ultravox doesn't check

## Tutorials

- [Create a voice for an Ultravox agent](https://www.anchorterminal.com/tutorials/ultravox-voice-cloning/), for Ultravox Voice Cloning

## Questions

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

Smallest.ai Instant Voice Clone scores 58 (C) on agent readiness against Ultravox Voice Cloning's 40.9 (E), and leads in 6 of 7 scored categories. Ultravox Voice Cloning leads on payments & pricing.

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

Both need an API key.

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

Yes. Smallest.ai Instant Voice Clone has a hosted endpoint at https://api.smallest.ai/waves/v1/voice-cloning and Ultravox Voice Cloning at https://api.ultravox.ai/api.


## For agents

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

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

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

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