Event-driven channels

Retell AI

Retell AI provides voice AI infrastructure for building conversational agents with low-latency turn detection, interruption handling, tool calling, knowledge bases, and conversation flows. The Retell SDK exposes a published OpenAPI spec covering agents, calls, voices, knowledge bases, conversation f

2 channels across 1 AsyncAPI spec · Provider profile

Channels

audio/{call_id}

Audio WebSocket channel (deprecated). Carries raw audio bytes from the frontend microphone to Retell, and a mix of raw audio bytes plus JSON / string control events from Retell back to the frontend.

Retell AI WebSocket APIs
custom_llm/{call_id}

Custom LLM WebSocket channel. Retell AI opens a connection to the developer's WebSocket server and exchanges JSON messages identified by `interaction_type` (Retell to LLM) or `response_type` (LLM to R

Retell AI WebSocket APIs