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Fish Audio · Voice model

S2 Pro

fish-audio/s2-pro
  • Voice
Released Jul 29, 2026

S2 Pro is a multilingual text-to-speech model from Fish Audio. It is suited for expressive narration and multi-speaker dialogue, with natural-language controls for speaking style and emotion.

Specifications

Input
text, up to 20,000 characters per call
Output
mp3 (default) or raw pcm
Voice
provider voice ids via `voice`; omitted = the provider's default when it has one
Billing
per character of input text

Use it

POST /api/v1/audio/speech · MCP speak · full reference

curl https://omnirail.org/api/v1/audio/speech \
  -H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
  -d '{"model":"fish-audio/s2-pro","input":"Hello from OmniRail. Every model, one key.","response_format":"mp3"}' \
  --output hello.mp3