Soniox Voice Cloning by Soniox

# Fix list: Soniox Voice Cloning

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/soniox-voice-cloning, the October 2026 research run, assessed 1 October 2026. Grade C, 58.8 out of 100.

This is everything the published grade says the listing lacks, the biggest possible gain to the total first. It comes from the reason given for each score, the checklist each category was scored against (https://www.anchorterminal.com/benchmark/#checklist), the provenance checks, the deductions, what we couldn't check and what the review panel asked for. A fix counts at the next check, once it's public.

For a coding agent working on Soniox Voice Cloning: work through the items below in the product, its docs and its public pages. Each category gives the reason for its score, with the points each checklist item earned, and the checklist itself, so the gap is the items that earned less than their points. Change the product, not the wording, and keep a note of what you changed and where it's published.

## 1. Payments & pricing, 20 out of 100, up to 10 more on the total

Why it scored 20: No x402, MPP or L402 (0). Per-unit prices are public, $4 per million input text tokens and $21.50 per million output audio tokens, about $0.70 an hour by Soniox's estimate, with no cloning fee (20). No free tier for new accounts (0). Signup is a human browser flow (0).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-payments):

The published rubric, also on the [x402 page](https://www.anchorterminal.com/x402/).

- 40, a machine payment protocol (x402, MPP or L402) on the tool's own endpoints. 10 to 30 when it covers only some endpoints or only goes through a third party, and the note says which.
- 20, per-call or per-unit pricing published without a login. 10 for public plan-only pricing, 0 for "contact sales" or prices behind a login.
- 20, a free tier or trial that doesn't need a card.
- 20, autonomous onboarding, meaning an agent can get access without a person signing up in a browser (keyless use, x402, a programmatic key API).

Payment platforms and agent wallets rarely charge for their own API over a machine protocol, so the first line has steps for them, and the highest one that applies counts. 40 when x402, MPP or L402 runs on all their own endpoints, 30 when it runs on part of their own API, 25 when their merchants can accept one, 20 for running a facilitator, 15 for paying as a buyer, and 0 when the only protocol is their own. Merchant acceptance sits above a facilitator because the platform's own customers can charge agents through it, while a facilitator settles for sellers who wire up the protocol themselves. The counter-argument (a facilitator does more for the protocol as a whole) has a point. Each note says which step applied.

Open-source software you run yourself is scored on its hosted or paid option if it has one. A free, self-hosted package with nothing to buy gets 20, 20 and 20 for the last three lines, and 0 to 40 for the first only if it ships a payment protocol.

## 2. Security & auth, 53 out of 100, up to 8.2 more on the total

Why it scored 53: 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. Project-scoped API keys plus temporary keys for client use (25 of 30). The terms say Soniox doesn't verify the right to clone a voice, and there's no consent step or watermark (0 of 20). Audio is never used to improve models, and a voice's clip stays until you delete the voice (15). Usage visible in the Console and every error carries a `request_id`, no per-call log found (8 of 15). SOC 2 Type 2 and ISO 27001:2022 stated, with reports in the Console, no security.txt, bug bounty or public trust centre found (5 of 20).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-security):

- 0 to 30, the credential model. 30 for OAuth 2.1 with scopes, or scoped and revocable keys with rotation. 20 for plain revocable API keys. 10 for one all-powerful key. 10 off when a secret can travel in a URL query string as a documented option.
- 0 to 20, read-only or least-privilege modes, and confirmation or approval for destructive actions.
- 0 to 15, prompt-injection posture where the tool returns untrusted content (documented mitigations or guidance). A tool that returns no untrusted content gets 10.
- 0 to 15, audit logs or per-call visibility for the operator.
- 0 to 20, a security programme. security.txt or a disclosure policy, a bug bounty, SOC 2 or ISO 27001, advisories handled in public.

Models are read for retention, whether API data trains models (and whether that's off by default), zero-retention options and certifications. Frameworks for telemetry defaults, approval hooks, guardrails and sandboxing.

## 3. Schema & documentation, 61 out of 100, up to 6.3 more on the total

Why it scored 61: No public OpenAPI file found (0). llms.txt and llms-full.txt (10). The cloning guide explains clip quality, statuses and when to recompute after a model release (14 of 20). Create takes a name and one file with documented size and length limits (12 of 15). A shared error reference with stable `error_type` slugs, `request_id` and a `more_info` link (15). Versioned `/v1` paths and release notes with deprecation guidance on the models page, but no general changelog (10 of 15).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-schema):

APIs and MCP servers.

- 25, a machine-readable contract (a public OpenAPI file or similar; for MCP, typed JSON Schema inputs on every tool).
- 10, llms.txt or Markdown docs served for agents.
- 0 to 20, descriptions that say what a tool is for, when to use it and when not to, read from the tool definitions in the source or the API reference.
- 0 to 15, typed inputs with enums, constraints and required fields, and no free-form JSON blobs.
- 0 to 15, examples and documented error responses.
- 15, versioning and a public changelog.

Models are read from the API reference, the OpenAPI file, llms.txt, the structured-output and tool-use docs and the model cards. Frameworks from docs a model can follow, typed interfaces, examples and the API reference.

## 4. Reliability, 73 out of 100, up to 5.4 more on the total

Why it scored 73: Status page at status.soniox.com (Instatus) with regional components and history (20). Three incidents in the last 90 days, none on TTS or voices, the longest 70 minutes of failed API key creation in the Console on 24 August, plus 45 minutes of partial STT errors in Japan and 9 minutes of failed EU WebSocket sessions (20). TTS REST limits published, 100 requests a minute, 3 concurrent and 20 voices per organisation (15). Over a limit the API returns `limit_exceeded` with advice to slow down, and 503s are marked for exponential backoff (8). No idempotency key or safe-retry guidance for voice creation (0). No SLA found (0). Voice cloning is part of the released TTS models, not a preview (10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-reliability):

Hosted APIs, MCP servers, models and platforms.

- 20, a public status page with component history (Statuspage, Instatus, BetterStack or the vendor's own).
- 0 to 30, the incident record for the last 90 days on that page. 30 for a clean record or trivial incidents only, 20 for minor incidents only, 10 for one major outage (an hour or more of a core API down, or errors across the board), 0 for several. 5 when there's no history we could read, and the note says so.
- 15, rate limits documented with numbers.
- 15, documented 429 or overload handling (Retry-After, backoff guidance), and idempotency keys or safe-retry guidance where writes are involved.
- 10, an SLA published for any paid tier.
- 10, the surface agents use is generally available, not beta or preview.

Local packages, SDKs, frameworks and stdio MCP servers.

- 20, installs from an official package with supported runtimes stated.
- 25, a public CI and test suite, passing on the default branch.
- 0 to 25, open crash or regression issues relative to activity (25 for few and handled, 0 for many, old and unanswered).
- 15, semver discipline and breaking changes called out in a changelog.
- 15, version 1.0 or later, or declared stable.

Protocols are read from their reference implementations, the public facilitators or servers, spec stability and test vectors.

## 5. Maintenance & community, 45 out of 100, up to 4.8 more on the total

Why it scored 45: tts-rt-v2 with high-fidelity cloning and @soniox/node 2.3.0 on 2026-08-11, 51 days ago (20 of 30). We confirmed one release in the last 90 days (0 of 20). Release notes on the models page, no answering support channel confirmed (5 of 15). Official SDKs in five flavours, Node released in August (15). SDK released within 90 days (5 of 10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-maintenance):

- 0 to 30, time since the last release, or the last published model or API change for a closed service. 30 within 30 days, 20 within 90, 10 within 180, 0 older.
- 20, at least three releases or dated changelog entries in the last 90 days.
- 0 to 25, responsiveness. Issues and pull requests answered on GitHub (the open issues and how recent the replies are). For closed services, a public changelog and a support or community channel that answers, 0 to 15.
- 15, presence in the official MCP registry under a verified namespace (MCP servers), or current official SDKs (APIs and models).
- 10, package health, current dependencies and CI.

Models are read for deprecation notice periods and model churn rather than release counts.

## 6. Agent ergonomics, 75 out of 100, up to 4.1 more on the total

Why it scored 75: Responses are small voice objects (20 of 25, we didn't confirm the list returns only your voices). List, get and delete endpoints exist, pagination not confirmed (10 of 20). Errors say which to retry and which are terminal, `voice_not_prepared` tells you to recompute (20). No idempotency key, voice processing has a per-model status to poll (10 of 20). Two required fields and SDKs for Python, Node, Web, React and React Native (15).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-ergonomics):

- 0 to 25, context cost. For MCP, the number and size of the tool definitions (25 for ten or fewer compact tools, 15 for 11 to 30, 5 for more than 30, plus up to 10 back for toolsets, dynamic loading or read-only subsets). For APIs, whether responses can be sized (field selection, limits, summaries).
- 20, pagination, filtering and output-size controls.
- 20, actionable, documented error responses, codes and messages an agent can recover from.
- 20, idempotency or safe retries, and for MCP the `readOnlyHint` and `destructiveHint` annotations.
- 15, sensible defaults, few required parameters, and official SDKs in at least two languages.

Models are read for tool use, structured output, prompt caching, context length, batch and SDKs. Frameworks for how much code and how many defaults a tool-calling agent with MCP needs.

## 7. Transparency & trust, 73 out of 100, up to 2.4 more on the total

Made of editorial 60, provenance 86.

Why it scored 73: Closed service with clear terms, SDKs open source (15 of 30). Terms and privacy updated 2026-06-29 agree that samples aren't used for training and stay until deleted, with Async data auto-deleted after 30 days, but we found no public DPA or subprocessor list (20 of 30). Deprecation guidance and model aliases on the models page (15 of 20). Data residency documented, with regions in the US, Europe, Japan and India, no subprocessor list found (10 of 20).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-transparency):

- 0 to 30, source availability and licence clarity. 30 for open source under an OSI licence, 15 for closed with clear terms, 0 for unclear terms.
- 0 to 30, data handling and retention statements that agree with each other (privacy policy, DPA, retention periods, subprocessors).
- 0 to 20, a deprecation policy or notices with dates.
- 0 to 20, telemetry disclosed with an opt-out (local software), or subprocessors and data locations disclosed (hosted).

The other half of Transparency and trust is the provenance score, computed from checked facts (below). The category score is the mean of the two.

Provenance checks not met in full (half of this category, computed from checked facts):

- Domain age: soniox.com, registered 2020-03-23 (6 years) (11 of 15)
- security.txt: not found (0 of 10)

## What we couldn't check

What we couldn't read counted as absent. Publishing it on a page a plain HTTP fetch can read (not only in a browser) lets the next check count it.

- Whether the voices list paginates and returns only custom voices
- Release count in the last 90 days beyond the 2026-08-11 SDK and model release
- The status page components aren't named in what we could read, so we couldn't confirm a TTS component
- security.txt was taken as absent from last week's check

## Weaknesses

- No consent capture or speaker verification, and the terms say so
- Instant clones only, no professional tier or voice design
- 20 voices per organisation and 3 concurrent TTS requests by default
- Voices must be recomputed by hand after a new TTS model ships
- No public OpenAPI file and no free tier

## What costs an agent a turn today

The notes we give agents before they call it. Each one is a workaround an agent shouldn't need.

- Poll the voice until the target model's status is `ready` before using it in TTS
- On `voice_not_prepared` call recompute, don't retry the TTS request
- Don't retry `voice_failed` even though it's a 503. Create a new voice from a better clip
- Use a key from the project that owns the voice, voices are per project
- Keep the clip under 2 minutes and 35 MB, longer fails with `voice_audio_too_long`

## What the review panel asked for

- Automatic voice recompute
- Public OpenAPI
- speaker consent verification

## When it's done

Send what changed and where it's published as a dispute (https://www.anchorterminal.com/builders/#disputes, or `POST https://www.anchorterminal.com/api/v1/contact` with `"kind": "dispute"`). Disputes are answered in public, and the listing is checked again by the same checklist. Paying for an audit or a listing claim changes nothing here.