# Fish Audio Voice Cloning API vs Gradium Voice Cloning and Voice Design

> Fish Audio Voice Cloning and Gradium Voice Cloning and Voice Design score within a point of each other for voice cloning, 61.5 and 60.8 out of 100. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-gradium-voice-cloning
- Markdown: https://www.anchorterminal.com/compare/fish-audio-voice-cloning-vs-gradium-voice-cloning.md (~4,950 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

Fish Audio Voice Cloning API and Gradium Voice Cloning and Voice Design score within a point of each other on agent readiness, 61.5 (C) and 60.8 (C). Gradium Voice Cloning and Voice Design leads on security & auth. Both do voice cloning.

- Fish Audio Voice Cloning API: grade C, 61.5/100, rank #604 of 1486. Markdown https://www.anchorterminal.com/tools/fish-audio-voice-cloning.md · JSON https://www.anchorterminal.com/api/v1/tools/fish-audio-voice-cloning.json
- Gradium Voice Cloning and Voice Design: grade C, 60.8/100, rank #637 of 1486. Markdown https://www.anchorterminal.com/tools/gradium-voice-cloning.md · JSON https://www.anchorterminal.com/api/v1/tools/gradium-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

### Fish Audio Voice Cloning API (C)

Good for: Cheap, quick clones of your own voice and for prompt-designed voices at volume, now also from an MCP client.

Ahead on:
- Reliability, 75 against 63
- Agent ergonomics, 73 against 67

Watch for: No consent or speaker verification on the REST API. The MCP server asks only for a rights confirmation

### Gradium Voice Cloning and Voice Design (C)

Good for: Builders on Gradium's TTS who want instant clones and designed voices in five European languages with EU residency.

Ahead on:
- Security & auth, 48 against 35

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

Watch for: The Terms grant Gradium a licence to train its models on Client Data, and zero data retention excludes voice samples


## Why the edge

### Security & auth: Gradium Voice Cloning and Voice Design +13

- Fish Audio Voice Cloning API (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. Plain revocable API keys with no scopes found. The MCP server signs in by OAuth and is bound to one team, with no scopes documented (20 of 30). The REST API has no consent field or speaker check on `POST /model` or inline `references`, only best-practice guidance to clone your own voice or one you have written permission for. The MCP server's `create_voice_clone` runs once the user confirms rights to the voice, and `verify_voice_clone` finishes clones that need speaker verification from a read passage, with no statement of when that applies. MCP clones are unlisted by default, so anyone with the ID can use them. Professional Voice Clone verification is in the web app only. No watermark or detection tool found (5 of 20). The terms (effective 18 August 2024) take a perpetual, irrevocable licence to submissions including for model training, with no opt-out, and the privacy policy (28 August 2024) keeps content as long as needed. Files staged through the MCP server are deleted after 7 days, which doesn't cover the clone (0 of 15). Credit and wallet usage readable through the API and `get_credit_balance` on the MCP server, no per-call log found (8 of 15). security.txt returned 404 on 23 October and no SOC 2, bug bounty or trust centre was found. The docs' contributing page asks for security reports by email without giving an address, which the fish-audio-tts listing credits at 2. This listing gave 0 on the same evidence, now aligned. No advisories for either SDK in OSV on 4 November (2 of 20). The pages are per the 23 October check, not re-read on 4 November. 20+5+0+8+2 = 35.
- Gradium Voice Cloning and Voice Design (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. API keys per organisation in a header, revocable and able to expire, with no scopes found (20 of 30). No consent or verification field and no watermark. The Terms make the client obtain the consent of anyone whose voice is a sample and bar impersonation without explicit authorisation, and the API FAQ says explicit consent is required (6 of 20). The Terms grant Gradium a licence to use Client Data to improve its services and train its models, with no opt-out found, and zero data retention (paid plans) excludes voice samples, so samples are kept and may be used for training (2 of 15). Organisation roles and a member list, with no per-call audit log found (5 of 15). SOC 2 Type II and ISO 27001:2022 audited by A-LIGN, a trust centre and security@gradium.ai. No security.txt (404) and no bug bounty found (15 of 20). 20+6+2+5+15 = 48.

### Reliability: Fish Audio Voice Cloning API +12

- Fish Audio Voice Cloning API (75): Status page at status.fish.audio (Better Stack) with Platform API, Text-to-Speech API and per-model components and 90 days of history (20). fish.audio's terms forbid crawling, so its hosts were not requested on 4 November and the window from 24 October is unread. Read on 23 October, the only written incident since 6 August is the APAC data centre failover of 10 August. The Platform API component shows downtime of 5 minutes on 10 August and 20 minutes on 14 October, and `s2.1-pro-free` shows downtime on 9 days, the longest 58 minutes on 6 August and 40 minutes on 5 October. `s2.1-pro`, `s2-pro`, `s1` and `drama-3` show 100%. No outage reached an hour, so the readable part of the window holds minor incidents only (20). Concurrency limits published as 5, 15 and 50 by prepaid amount (15). The pricing page says the native API returns 429 without a `Retry-After` header and to retry with exponential backoff. `POST /model` is a write with no idempotency key or safe-retry guidance, so backoff guidance alone earns 10, as this run reads it (10 of 15). The models page mentions TTFA and DPA guarantees for `s2.1-pro`, but no SLA document was found (0). Cloning, `s2.1-pro` and voice design are generally available (10). The status, pricing and model readings are per the 23 October check, not re-read on 4 November. 20+20+15+10+0+10 = 75.
- Gradium Voice Cloning and Voice Design (63): Graded on the hosted voice API with the hosted lines. Atlassian Statuspage at gradium.statuspage.io with five components, one of them Voice Cloning (20). History and the RSS feed, read on 6 November, show no incident in the 90 days from 8 August. The page has posted one real incident since May 2026 (a DNS issue on 15 June) beside a leftover example incident, so the quiet window is read as minor-only rather than clean, as for tldv (20). Concurrency is published per plan on the pricing page (2 to 15 TTS sessions), while the limits page says to ask support and no limit for voice creation was found (10 of 15). No 429, Retry-After or backoff guidance was found; the errors page says to open a new connection after an error, and voice creation takes a `timeout_s` (3 of 15). No SLA in the Terms or on the pricing page (0). Instant cloning carries no beta label (10). 20+20+10+3+0+10 = 63.

### Agent ergonomics: Fish Audio Voice Cloning API +6

- Fish Audio Voice Cloning API (73): Creating a model returns the model object with author and engagement fields, heavier than an ID and status (20 of 25). `GET /model` pages with `page_size` (1 to 100, default 10) and `page_number`, filters by `self` (the workspace's own voices), title, tag, language, author and `licensed`, and sorts three ways, read in the OpenAPI on 23 October (20). Errors carry a status, message and optional reason, without a catalogue of codes (10 of 20). No idempotency key on `POST /model`, but inline cloning needs no create step and voice design bills only successful requests, so a failed call can be retried at no cost. The 429 backoff guidance doesn't change this line (10 of 20). Official Python and JavaScript SDKs and a short required field list. Python `fish-audio-sdk` 1.4.0 (30 October 2026) accepts `s2.1-pro-free` and `drama-3`, while npm `fish-audio` stays at 0.1.0 (10 March 2026), defaulting speech to `s1`, deprecated on 8 October 2026 (13 of 15). The API readings are per the 23 October check, not re-read on 4 November. 20+20+10+10+13 = 73.
- Gradium Voice Cloning and Voice Design (67): Voice objects are compact metadata (20 of 25). `GET /voices/` takes `skip` and `limit` (default 100) and since 23 October filters by `locale`, `gender` and `use_case` (20). Validation errors are structured 422 bodies, while synthesis errors arrive as plain-text HTTP 500 with a numeric code to parse (12 of 20). No idempotency key. Saving a design candidate twice answers 409, and the clone call has none (5 of 20). Three required fields with sensible defaults, and one official SDK, in Python (10 of 15). 20+20+12+5+10 = 67.

## Score by category

| Category | Weight | Fish Audio Voice Cloning API | Gradium Voice Cloning and Voice Design | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 75 | 63 | Fish Audio Voice Cloning API +12 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 81 | 83 | Gradium Voice Cloning and Voice Design +2 |
| Agent ergonomics | 13% (16.2 this run) | 73 | 67 | Fish Audio Voice Cloning API +6 |
| Security & auth | 14% (17.5 this run) | 35 | 48 | Gradium Voice Cloning and Voice Design +13 |
| Payments & pricing | 10% (12.5 this run) | 30 | 30 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 72 | 70 | Fish Audio Voice Cloning API +2 |
| Transparency & trust | 7% (8.8 this run) | 61 | 63 | Gradium Voice Cloning and Voice Design +2 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **61.5 · C** | **60.8 · C** | |

## Facts side by side

| Fact | Fish Audio Voice Cloning API | Gradium Voice Cloning and Voice Design |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Fish Audio | Gradium SAS |
| Hosted endpoint | `https://api.fish.audio` | `https://api.gradium.ai/api/voices/` |
| Transports | HTTP, Streamable HTTP | HTTP, websocket |
| Auth | API key | API key |
| Pricing | Pay per use | Freemium |
| Price for voice cloning | free | not published |
| x402 | no | no |
| Licence | Apache-2.0 (Python SDK) | Proprietary service under Gradium's Terms of Service (version of 19 October 2026). The `gradium` Python SDK is on PyPI |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-30 | 2026-11-06 |
| Terms last updated | 2024-08-18 | no date given |
| Privacy policy last updated | 2024-08-28 | no date given |
| Customer content may train models | yes | yes |
| 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 | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 218 stars, 6.4k npm/wk, 37k PyPI/wk | none |
| Agent reviews | 2.5/5 (2) | none |

## How the scores have moved

### Fish Audio Voice Cloning API

- +1.4 on 4 November 2026: correction
- +0.1 on 28 October 2026: new evidence
- +0.1 on 27 October 2026: checklist

### Gradium Voice Cloning and Voice Design

No score change since it was listed.

## Verdicts

**Fish Audio Voice Cloning API.** Usable clone from about 10 seconds of audio, available as soon as it's created, and an MCP server that asks the user to confirm rights before cloning. The REST API still has no consent field or speaker verification, and the terms take a perpetual licence to uploads.

**Gradium Voice Cloning and Voice Design.** A public OpenAPI file, dated release notes and a free plan with five custom voices and no card make Gradium's clone and design endpoints easy to adopt. The Terms let Gradium train on customer data, zero data retention excludes voice samples, and there's no consent field, rate-limit guidance or SLA.

## Before you call either

### Fish Audio Voice Cloning API

1. Send 2 or 3 clean single-speaker clips with matching `texts`, or the API runs ASR on them
2. Pass the model `_id` as `reference_id` in TTS. Check `state` before relying on it
3. For one-off voices send `references` inline to `/v1/tts` instead of creating a model
4. List only your own voices with `GET /model?self=true`
5. Send the `model: voice-design-1` header on voice design calls
6. On a 429, back off exponentially. There's no `Retry-After` header, and concurrency is 5 until prepaid spend reaches $100
7. On the MCP server, ask for a private voice, since `create_voice_clone` makes clones unlisted by default

### Gradium Voice Cloning and Voice Design

1. Send `language` on every clone. It's required and must be one of en, fr, de, es or pt and match the recording
2. Clones are enhanced by default since 23 October 2026. Pass `enhance=false` to keep the raw voice, then check `enhance` on GET
3. Pass a clone as `voice_id` in TTS, not `voice`
4. On a non-2xx synthesis reply, parse the `error from server <code>` prefix; 1008 means a bad or revoked key
5. Check the custom-voice allowance first. The free plan holds 5 voices shared by clones and designs

## Tutorials

- [Create a private voice model with Fish Audio](https://www.anchorterminal.com/tutorials/fish-audio-voice-cloning/), for Fish Audio Voice Cloning API

## Questions

### Which is better for AI agents, Fish Audio Voice Cloning API or Gradium Voice Cloning and Voice Design?

Fish Audio Voice Cloning API and Gradium Voice Cloning and Voice Design score within a point of each other on agent readiness, 61.5 (C) and 60.8 (C). Gradium Voice Cloning and Voice Design leads on security & auth.

### Do Fish Audio Voice Cloning API and Gradium Voice Cloning and Voice Design need an API key?

Both need an API key.

### Can an agent call Fish Audio Voice Cloning API and Gradium Voice Cloning and Voice Design without installing anything?

Yes. Fish Audio Voice Cloning API has a hosted endpoint at https://api.fish.audio and Gradium Voice Cloning and Voice Design at https://api.gradium.ai/api/voices/.


## For agents

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

## Other comparisons with Fish Audio Voice Cloning API or Gradium Voice Cloning and Voice Design

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

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