# Cartesia Voice Cloning API + MCP vs Gradium Voice Cloning and Voice Design (slim)

> Gradium Voice Cloning and Voice Design scores 60.8 (C) to Cartesia Voice Cloning's 58.3 (C) for voice cloning. Prices, MCP, x402, uptime and agent notes side by side.

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- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07
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Gradium Voice Cloning and Voice Design scores 60.8 (C) on agent readiness against Cartesia Voice Cloning API + MCP's 58.3 (C), and leads in 3 of 7 scored categories. Cartesia Voice Cloning API + MCP leads on reliability, maintenance & community and transparency & trust. Both do voice cloning.

- Cartesia Voice Cloning API + MCP: C 58.3, rank #755 of 1510 · https://www.anchorterminal.com/tools/cartesia-voice-cloning.min.md
- Gradium Voice Cloning and Voice Design: C 60.8, rank #640 of 1510 · https://www.anchorterminal.com/tools/gradium-voice-cloning.min.md
- Cartesia Voice Cloning API + MCP, good for Teams that want cheap instant clones and fast streaming TTS in the same account, especially voice agents. Ahead on Reliability, 73 against 63; Maintenance & community, 84 against 70; Transparency & trust, 73 against 63. Also Runs on your own machine.
- Gradium Voice Cloning and Voice Design, 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 42; Payments & pricing, 30 against 10. Also Free to start without a card; No incidents deducted, where Cartesia Voice Cloning API + MCP loses 3 points for them.

| Category | Cartesia Voice Cloning API + MCP | Gradium Voice Cloning and Voice Design |
| --- | --- | --- |
| Reliability (16%) | 73 | 63 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 85 | 83 |
| Agent ergonomics (13%) | 65 | 67 |
| Security & auth (14%) | 42 | 48 |
| Payments & pricing (10%) | 10 | 30 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 84 | 70 |
| Transparency & trust (7%) | 73 | 63 |

| Fact (where they differ) | Cartesia Voice Cloning API + MCP | Gradium Voice Cloning and Voice Design |
| --- | --- | --- |
| Vendor | Cartesia | Gradium SAS |
| Hosted endpoint | `https://api.cartesia.ai` | `https://api.gradium.ai/api/voices/` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, websocket |
| Auth | OAuth or key | API key |
| Licence | Apache-2.0 (SDKs) | Proprietary service under Gradium's Terms of Service (version of 19 October 2026). The `gradium` Python SDK is on PyPI |
| Tools exposed | 19 | none |
| Last release | 2026-10-30 | 2026-11-06 |
| Terms last updated | 2024-06-14 | no date given |
| Privacy policy last updated | 2024-06-14 | no date given |
| Customer content may train models | yes, with an opt-out | yes |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 133 stars, 166k npm/wk, 177k PyPI/wk | none |
| Agent reviews | 2.5/5 (2) | none |

Why the edge:
- Payments & pricing, Gradium Voice Cloning and Voice Design +20: Cartesia Voice Cloning API + MCP 10 (No x402, MPP or L402 (0). Plan prices are public and instant cloning is included from Pro at $5 a month, Pro cloning from Startup at $49, but there's no dollar price per unit, only credits (10). The Free plan has no cloning, re-read on 4 November (0). Signup is a human browser flow (0). 0+10+0+0 = 10.); Gradium Voice Cloning and Voice Design 30 (No x402, MPP or L402 (0). Plan prices and credits are public, 1 credit a character for speech, with no dollar price per unit, as cartesia-voice-cloning is read. Creating a clone uses no credits in the docs (10). The free plan has 45,000 credits a month, 5 custom voices and Voice Design, and the site says no credit card is required. Commercial use starts on the $12 plan (20). Signup is a browser flow in Gradium Studio (0). 0+10+20+0 = 30.)
- Maintenance & community, Cartesia Voice Cloning API + MCP +14: Cartesia Voice Cloning API + MCP 84 (Read as a model, on the lines cartesia-tts, cartesia-ink-stt and the other hosted speech models use (recency 30, dated releases 10, deprecation notice 10, support 15, issues 10, SDKs 15, health 10); the 1 October check used the tool lines. `cartesia-mcp`, whose `clone_voice` and `localize_voice` tools call the cloning API, released 0.28.1 on 30 October 2026 after 0.26.1 (8 October), 0.27.0 (20 October), 0.27.1 (23 October) and 0.28.0 (27 October) (30). From 6 August the Python and TypeScript SDKs released 4.0.0, 4.0.1, 4.1.0 and 4.2.0 (14 August to 2 September) and the MCP server more than ten releases (10). Sonic-2, Sonic Turbo and `sonic-3-2025-10-27` were sunset after 20 October 2026, announced in the July changelog, and the deprecations page states no minimum notice period (5 of 10). The changelog has Voices entries every month from May to September 2026, dated by month only, and no October entry (11 of 15, as cartesia-tts). The Python SDK repository had 4 open issues on 9 October per the cartesia-ink-stt check, not re-read since GitHub's pages answered 403 (5 of 10). Official `cartesia` and `@cartesia/cartesia-js` SDKs at 4.2.0 (2 September 2026), generated for API version 2026-08-14 (15). CI (test.yml), release-please and lock files, with dependency updates merged on 23 October (8 of 10). 30+10+5+11+5+15+8 = 84.); 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.)
- Reliability, Cartesia Voice Cloning API + MCP +10: Cartesia Voice Cloning API + MCP 73 (incident.io status page at status.cartesia.ai with a Voice Cloning component and a dated history (20). feed.rss, read on 4 November, lists these items touching Voice Cloning from 6 August to 4 November 2026. 7 August "Agents Telephony failing in the US" lists every component in the feed, but its incident page names only Voice Agents, as a partial outage. 4 September "Intermittent issues with voice cloning in APAC" (about 21 hours across 3 and 4 September per the 1 October reading), one region. 7 October "Degraded API Performance in US Regions", US only. 23 October "Elevated latency for instant voice cloning", latency. Each is partial and minor under this run's incident rule, and the 1 August API-wide major has left the window. Minor incidents only (20; was 10), as cartesia-tts and cartesia-ink-stt on the same page. Concurrency limits per plan are published, 2 to 15 TTS requests (15). A 429 is documented when the limit is hit, with no Retry-After or backoff guidance in the docs, but the official SDK README says it retries 429 and 5xx twice with exponential backoff, and there is no idempotency key or safe-retry guidance for clone creation (8). No SLA published (0). Instant cloning is generally available (10). 20+20+15+8+0+10 = 73.); 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.)
- Transparency & trust, Cartesia Voice Cloning API + MCP +10: Cartesia Voice Cloning API + MCP 73 (Closed service with clear terms (last revised 14 June 2024, re-read 4 November), SDKs under Apache-2.0 (15 of 30). Privacy policy (dated 14 June 2024), a DPA with 90 and 180 day post-termination windows and transfer clauses, and a subprocessor list behind the trust centre, but no retention period for voice samples (20 of 30). Dated deprecation notices in the changelog, such as Sonic-2 sunset after 20 October 2026 announced in July, without a written notice policy (15 of 20). Subprocessors sit in the trust centre, which we couldn't read without a browser, and regional endpoints are documented for Enterprise, while the privacy policy names no data locations (10 of 20).); 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.)
- Security & auth, Gradium Voice Cloning and Voice Design +6: Cartesia Voice Cloning API + MCP 42 (Graded on the model lines with the voice-cloning substitutions this run uses (consent and misuse controls in place of the read-only line, training and retention of voice data in place of the prompt-injection line), on the same evidence and values as cartesia-tts and cartesia-ink-stt where it is shared. Standard and admin API keys are separate types, revocable, and a server can mint short-lived access tokens with TTS, STT and agent grants, but no key or grant is scoped to cloning (26). Browsers pass the access token in the WebSocket query string, which the authentication guide documents ("In browsers, use an access token and query parameters instead"), so the full 10 comes off, as for cartesia-tts and cartesia-ink-stt (16 of 30; was 25). The clone API takes `clip`, `name` and `language` with no consent field or speaker check, the Acceptable Use Policy asks for the speaker's explicit consent, and no watermark or detection tool was found (0 of 20). The Terms (last revised 14 June 2024, re-read 4 November) allow training on inputs unless otherwise agreed, with an opt-out form, zero data retention "is not available for voice cloning, PVC, voice creation", and no retention period for samples is published beyond a post-termination window in the DPA (5 of 15). Usage totals in the dashboard and through an admin-key endpoint, no per-call log found (7 of 15, aligned with cartesia-tts; was 8). security.txt at www.cartesia.ai is valid until 3 October 2027 with a contact and a policy link to the trust centre, and SOC 2 Type II, HIPAA and PCI-DSS are stated. The trust centre is drawn by script and wasn't read, and no bug bounty was found (14 of 20; the 1 October check found no security.txt, 10). 16+0+5+7+14 = 42.); 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.)