Varosity

Cartesia Sonic 3 API

$0.378/min on Varosity credits ($0.360/min with your own key).

Try Cartesia Sonic 3 Get an API key

no cartesia account needed · no subscription · failed renders never billed

Best for

  • ~90ms TTFA
  • 42 languages
  • AI laughter + emotion
  • streaming-native

Trade-offs

  • voice ids are library-specific — call list_voices

Call it from your code

One Varosity key works for every model.

curl -X POST https://varosity.ai/api/v1/tts \
  -H "Authorization: Bearer $VAROSITY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Welcome to the launch. Here's what's new this week.",
    "voiceModel": "cartesia-sonic-3"
  }'

Or ask your agent

Connect Claude, Cursor, or any MCP client to https://varosity.ai/api/mcp with your key, then say:

"Use Varosity with cartesia-sonic-3 to read this script aloud: …"
Agent setup guide

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