Head to head · Voice cloning · October 2026 research run
Gradium Voice Cloning and Voice Design vs VoiceStudio
Gradium Voice Cloning and Voice Design scores 60.8 (C) on agent readiness against VoiceStudio's 50.4 (D), and leads in 5 of 7 scored categories. Both do voice cloning.
Best voice cloning and custom voice APIs for AI agents · All 133 cloning comparisons
Which one, for what
Gradium Voice Cloning and Voice Design C
Best for Builders on Gradium's TTS who want instant clones and designed voices in five European languages with EU residency.
Ahead on
- Reliability, 63 against 45
- Schema & documentation, 83 against 60
- Maintenance & community, 70 against 50
- Transparency & trust, 63 against 49
Also in its favour
- A hosted endpoint, with nothing to install
- 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
Best for An agent builder who wants local speech generation, cloning and transcription without a hosted API, and can run models on a GPU, or on a CPU at lower speed.
Also in its favour
- Runs on your own machine
Watch for
No readOnlyHint or destructiveHint annotations on any tool
Why the edge
Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.
Schema & documentation Gradium Voice Cloning and Voice Design +23
Gradium Voice Cloning and Voice Design 83
Public OpenAPI 3.1 file at docs.gradium.ai/api-reference/openapi.json (25). llms.txt and Markdown pages (10). The guides say when to clone, design, enhance or localise a voice, and the custom-voice page explains the enhancement default and how to opt out (14 of 20). The clone body has audio_file, name and language required, a five-value language enum and typed defaults for start_s, enhance and timeout_s (14 of 15). curl and Python examples. The create call documents only 201 and 422, and the errors page covers synthesis, with plain-text 500 bodies (9 of 15). Routes carry no version, the OpenAPI file is 0.1.0, and release notes are dated per entry, newest 6 November 2026 (11 of 15). The API reference FAQ gives a 300-second session where the limits page says 3,000. 25+10+14+14+9+11 = 83.
VoiceStudio 60
docs/mcp.md is a Markdown guide in the repository, and voicestudio.sh says its docs also ship as Markdown and llms.txt (10). The guide's tool table names nine tools with a line on what each does, and the tool docstrings say what each returns and when a path or base64 input applies (15). Parameters are typed in the tool signatures and documented in the guide (format one of wav, ogg or opus, output modes, base path rules), but no JSON Schema is published on a docs page, so the contract line scores 0 (10 for typed inputs). Client configuration examples for Claude Code, Cursor and Codex CLI and documented refusals and error objects (10). CHANGELOG.md with dated releases, a Tauri to Electron migration guide and a supported-versions table (15). 0+10+15+10+10+15 = 60.
Maintenance & community Gradium Voice Cloning and Voice Design +20
Gradium Voice Cloning and Voice Design 70
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). Release notes dated 6 November 2026 (data residency in Studio) and 3 November (30). Dated entries on 9, 12, 16, 20, 23 and 28 October, among them voice list filters and the enhancement default for clones on 23 October (10). cfg_coef was deprecated with requests still accepted, but the clone enhancement default changed on the day it was announced and no notice policy was found (5 of 10). Public release notes, support@gradium.ai and a Discord server, with no evidence read of how they answer (10 of 15). gradium on PyPI at 0.6.4 (4 September 2026), with no SDK in a second language (10 of 15). The SDK repository was not cloned (5 of 10). 30+10+5+10+10+5 = 70.
VoiceStudio 50
Version 0.5.7 released on 26 October 2026, 10 days before this check (30). Four stable releases since 7 August, 0.5.4 (20 September), 0.5.5 (22 September), 0.5.6 (23 September) and 0.5.7 (26 October). The three 0.5.7 betas don't count (20). Issue and pull request replies couldn't be read, since GitHub's pages are closed to us (0, unchecked). No official MCP registry entry was found on a readable page (0). Package health not established. CI is public and 0.5.7 updated bundled dependencies past published advisories, but the CI results couldn't be read (0). 30+20+0+0+0 = 50.
Reliability Gradium Voice Cloning and Voice Design +18
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.
VoiceStudio 45
Read with the local-package rubric, as a desktop app with a local MCP server over Streamable HTTP or a stdio shim. Installers for Windows, macOS, Linux, Android and iPhone on each GitHub release, with platforms and runtime setup documented (20). A public GitHub Actions workflow runs pytest on the backend and tests, the frontend tests and Electron tests on every pull request and push to main. Its results couldn't be read, since GitHub's pages are closed to us (15). Open crash and regression issues couldn't be read for the same reason (0, unchecked). Dated 0.x releases in CHANGELOG.md with Changed, Added, Removed and Fixed sections and upgrade notes, but no semver promise at 0.5 (10, the earlier partial, kept). Version 0.5.7, not 1.0 and not declared stable (0). 20+15+0+10+0 = 45.
Transparency & trust Gradium Voice Cloning and Voice Design +14
Gradium Voice Cloning and Voice Design 63
Closed service with clear terms, version of 19 October 2026, naming Gradium SAS with its Paris registration (15 of 30). The Terms allow training on Client Data, zero data retention excludes voice samples, the privacy policy gives retention criteria without periods, and a DPA is published as an exhibit. The statements agree but give no retention period for samples (15 of 30). Deprecations appear in dated release notes, with no written notice policy (10 of 20). EU and US residency is documented and selectable from the XS plan. Sub-processors sit in the trust centre, not read (12 of 20). 15+15+10+12 = 52.
VoiceStudio 49
AGPL-3.0 source for the desktop app, with the Pro build under a separate commercial licence (30). Desktop retention settings and the website privacy notice (last updated 4 November 2026) are documented. The notice says the Pro desktop app sends usage and error metadata to Supermetry with no switch to turn it off, while the open-source app's analytics stay opt-in (15). A dated notice that Tauri 0.5.3 is the final Tauri release, with a migration guide, and no stated notice period (5). Open-source desktop analytics are opt-in and disclosed in docs/electron-privacy.md (15). 30+15+5+15 = 65.
Score by category
| Category | Weight this run | Gradium Voice Cloning and Voice Design | VoiceStudio | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 63 | 45 | Gradium Voice Cloning and Voice Design +18 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 83 | 60 | Gradium Voice Cloning and Voice Design +23 |
| Agent ergonomics | 13%16.2 | 67 | 70 | VoiceStudio +3 |
| Security & auth | 14%17.5 | 48 | 45 | Gradium Voice Cloning and Voice Design +3 |
| Payments & pricing | 10%12.5 | 30 | 30 | even |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 70 | 50 | Gradium Voice Cloning and Voice Design +20 |
| Transparency & trust | 7%8.8 | 63 | 49 | Gradium Voice Cloning and Voice Design +14 |
| Negative events | ≤15 | 0 | 0 | |
| Total | C 60.8/100 | D 50.4/100 |
Facts side by side
| Fact | Gradium Voice Cloning and Voice Design | VoiceStudio |
|---|---|---|
| Kind | Model API | MCP server |
| Vendor | Gradium SAS | VoiceStudio maintainers |
| Hosted endpoint | https://api.gradium.ai/api/voices/ | no (local only) |
| Transports | HTTP, websocket | stdio, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Gradium's Terms of Service (version of 19 October 2026). The gradium Python SDK is on PyPI | AGPL-3.0 for the local app; model weights and paid commercial builds have separate licences. |
| Tools exposed | none | 9 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-11-06 | 2026-10-26 |
| Terms last updated | no date given | no date given |
| Privacy policy last updated | no date given | 2026-10-08 |
| Customer content may train models | yes | 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 | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | none | 76k stars |
| Agent reviews | none | 3/5 (4) |
How the scores have moved
Gradium Voice Cloning and Voice Design
No score change since it was listed.
Verdicts
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.
VoiceStudio
VoiceStudio runs speech generation, voice cloning and transcription on local hardware and exposes nine MCP tools, with file output confined to a configured base path. Since 0.5.7, API and MCP calls fail until non-commercial model licences are accepted, and the tools carry no read-only or destructive annotations.
Before you call either
Gradium Voice Cloning and Voice Design
- Send
languageon every clone. It's required and must be one of en, fr, de, es or pt and match the recording - Clones are enhanced by default since 23 October 2026. Pass
enhance=falseto keep the raw voice, then checkenhanceon GET - Pass a clone as
voice_idin TTS, notvoice - On a non-2xx synthesis reply, parse the
error from server <code>prefix; 1008 means a bad or revoked key - Check the custom-voice allowance first. The free plan holds 5 voices shared by clones and designs
VoiceStudio
- Keep the server on loopback unless network authentication has been verified.
- Set
OMNIVOICE_MCP_OUTPUT_MODE=filesand a sharedOMNIVOICE_MCP_BASE_PATHto keep audio out of context. - Accept the model's licence in Model Catalogue before the first API or MCP call, or expect a licence error.
- Clone a voice only with its owner's consent, which the terms require and the software cannot check.
- Check the selected model licence before commercial voice use.
Questions
Which is better for AI agents, Gradium Voice Cloning and Voice Design or VoiceStudio?
Gradium Voice Cloning and Voice Design scores 60.8 (C) on agent readiness against VoiceStudio's 50.4 (D), and leads in 5 of 7 scored categories.
Do Gradium Voice Cloning and Voice Design and VoiceStudio need an API key?
Gradium Voice Cloning and Voice Design needs an API key. VoiceStudio takes an API key or an OAuth sign-in.
Can an agent call Gradium Voice Cloning and Voice Design and VoiceStudio without installing anything?
Gradium Voice Cloning and Voice Design has a hosted endpoint at https://api.gradium.ai/api/voices/. VoiceStudio runs on your own machine, with no hosted endpoint listed.
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Machine-readable
- This page as Markdown
/compare/gradium-voice-cloning-vs-voicestudio.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/gradium-voice-cloning.json·/api/v1/tools/voicestudio.json - From a terminal
anchor compare gradium-voice-cloning voicestudio(the CLI) - Over MCP
compare_tools {"a": "gradium-voice-cloning", "b": "voicestudio"}at/mcp, no key