AsyncAPI channel · Twilio · Twilio Real-Time WebSocket APIs

conversation-relay

Single ConversationRelay WebSocket session. All frames are JSON-encoded text frames carrying a `type` discriminator. The session begins with a `setup` message and continues with `prompt`, `dtmf`, `interrupt`, and `error` frames from Twilio. The customer server streams back `text` tokens, `play` media, `sendDigits` DTMF, `language` switches, and an `end` directive to terminate the session.

Open source AsyncAPI → All Twilio channels Twilio provider profile
Provider: Twilio AsyncAPI: v2.6.0 Spec: Twilio Real-Time WebSocket APIs Operations: 2 Messages: 10

Channel address

conversation-relay

Operations

publish
relaySendToTwilio
Frames sent FROM the customer server TO Twilio.
relayReceiveFromTwilio
Frames sent FROM Twilio TO the customer server.

Messages

text
Streams an individual TTS text token (or final token) to Twilio.
Content-Type: application/json
play
Requests Twilio to play an external media file to the caller.
Content-Type: application/json
sendDigits
Sends DTMF digits down the call leg.
Content-Type: application/json
language
Switches the TTS and/or STT language mid-session.
Content-Type: application/json
end
Ends the ConversationRelay session and hands the call back to TwiML.
Content-Type: application/json
setup
Sent immediately after the WebSocket connection establishes.
Content-Type: application/json
prompt
Transcribed caller speech, streamed as the caller talks.
Content-Type: application/json
dtmf
A DTMF key pressed by the caller.
Content-Type: application/json
interrupt
Caller speech interrupted in-progress TTS playback.
Content-Type: application/json
error
Session-level error reported by Twilio.
Content-Type: application/json

About AsyncAPI

The AsyncAPI specification describes event-driven APIs the way OpenAPI describes request/response APIs. A channel is the named pipe — a webhook URL, a Kafka topic, a WebSocket route, an MQTT subject — that producers and consumers publish or subscribe to. Each channel carries one or more messages with structured payloads, and an operation declares whether a given party sends or receives on that channel.

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