fish.audio TTS

Requires FISH_AUDIO_API_KEY in .env (create one at https://fish.audio/go-api/api-keys/). Create voice models in the fish.audio playground and pass their id as reference_id to reuse a cloned voice.

Current API

Single synchronous call returning raw audio bytes:

POST https://api.fish.audio/v1/tts
Authorization: Bearer ${FISH_AUDIO_API_KEY}
Content-Type: application/json
model: <backend model>     # HTTP header selects the backend, e.g. s1

The backend model is chosen with the model HTTP header, not a body field. In OpenMontage this maps to the tool's model input.

Backend models

model is required, there is no default. Pass one of:

• s2.1-pro, latest generation. Best quality: inline emotion tags, 80+ languages, multi-speaker. Hero narration.
• s2.1-pro-free, promotional free access to s2.1-pro. Drafts, samples, and validation runs at $0 during the promo window only. Per the fish.audio announcement: free through August 31, 2026, subject to Fair Use, no SLA/latency guarantee, requests may be retained, and commercial use is restricted. Never route production or client narration through it.
• s2-pro, first S2 generation. Stable high quality with emotion-tag support.
• s1, previous flagship. Kept for compatibility with existing integrations.

Billing is per UTF-8 byte of input text (not per character). CJK text and emoji cost 3-4x an ASCII character of the same visible length. Current list pricing: s1 / s2-pro / s2.1-pro = $15 per 1M bytes, s2.1-pro-free = $0 during the promo window only (the tool's estimate_cost() switches to the paid s2.1-pro rate after August 31, 2026). Verify current pricing at https://docs.fish.audio/developer-guide/models-pricing/pricing-and-rate-limits before large batches.

Inline emotion tags (S2 models only)