Cartesia Voice Cloning API + MCP vs ElevenLabs Voice Cloning and Voice Design API

Cartesia Voice Cloning API + MCP

Instant clones from 10 seconds of audio, up to 60 seconds used on Sonic 3.6. No consent or speaker verification in the clone API.

ElevenLabs Voice Cloning and Voice Design API

Instant clones from 1 to 2 minutes of audio on the $6 Starter plan. Instant clones rely on an attestation, not a check.

Cartesia Voice Cloning API + MCP

1. Send Cartesia-Version on every call. The clone endpoint lists it as a required header
2. Pass the speaker's recorded language. A clone is built from one language, add others with the accents API
3. Keep IVC uploads under 16 MB
4. Don't blind-retry POST /voices/clone. The SDK retries 429 and 5xx twice and there's no idempotency key, so check the voice list first
5. Poll a Pro clone fine-tune until it finishes before using the voice ID

ElevenLabs Voice Cloning and Voice Design API

1. Keep the source samples. A clone can't be downloaded and re-cloning sounds slightly different
2. Check requires_verification in the create response before using the voice ID
3. List your own clones with GET /v2/voices?category=cloned instead of paging the whole library
4. On system_busy retry with backoff. On too_many_concurrent_requests queue instead, the plan cap won't lift
5. PVC is asynchronous. Create, add samples, verify, train, then poll fine_tuning_state