AsyncAPI channel · Cartesia · Cartesia Realtime WebSocket API (TTS + STT)

/tts/websocket

Multiplexed realtime TTS generation. The client opens one WebSocket and may run many concurrent generations, each identified by a unique `context_id`. Sending additional messages with `continue: true` on the same `context_id` extends that context's generation while preserving prosody. A `cancel: true` message stops a context's generation early.

Open source AsyncAPI → All Cartesia channels Cartesia provider profile
Provider: Cartesia AsyncAPI: v2.6.0 Spec: Cartesia Realtime WebSocket API (TTS + STT) Operations: 2 Messages: 8

Channel address

/tts/websocket

Operations

publish
sendTtsGenerationRequest
Send a TTS generation (or cancel) request.
receiveTtsStreamEvents
Receive audio chunks, timestamps, and control messages for a context.

Messages

TtsGenerationRequest
TTS generation request
Content-Type: application/json
TtsCancelRequest
TTS cancel request
Content-Type: application/json
TtsAudioChunk
Streamed audio chunk
Content-Type: application/json
TtsWordTimestamps
Word-level timestamps
Content-Type: application/json
TtsPhonemeTimestamps
Phoneme-level timestamps
Content-Type: application/json
TtsFlushDone
Flush acknowledgement
Content-Type: application/json
TtsDone
Generation completion signal
Content-Type: application/json
TtsError
Error response
Content-Type: application/json

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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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