Pipecat exposes two Async service classes:| Service class | Transport | Streaming |
|---|
AsyncAITTSService | WebSocket (persistent) | Low-latency chunks |
AsyncAIHttpTTSService | HTTP (per‑request) | Response streaming |
AsyncAITTSService is recommended for interactive use because it streams audio chunks as soon as they are ready, minimising time‑to‑first‑byte (TTFB).
Prerequisites#
(Optional) preferred Async voice ID
Installation#
Quick‑start (WebSocket)#
Handling interruptions#
AsyncAITTSService automatically stops synthesis on user interruption or when it receives a TTSUpdateSettingsFrame, enabling natural, back‑and‑forth voice experiences.
Troubleshooting#
| Symptom | Likely cause | Fix |
|---|
| ValueError: Missing ASYNCAI_API_KEY | Env var not exported | export ASYNCAI_API_KEY=... |
| Long TTFB (>1 s) | Using HTTP service / cold start | Switch to WebSocket & keep connection warm |
| ErrorFrame quota exceeded | Character quota exhausted | Upgrade plan |
Next steps#
Modified at 2025-08-01 13:07:39