AsyncAPI channel · AssemblyAI · AssemblyAI Universal Streaming Speech-to-Text API

/v3/ws

Single full-duplex WebSocket channel for a Universal Streaming session. The client publishes binary PCM audio chunks and JSON control messages, and subscribes to JSON event messages emitted by the server.

Open source AsyncAPI → All AssemblyAI channels AssemblyAI provider profile
Provider: AssemblyAI AsyncAPI: v2.6.0 Spec: AssemblyAI Universal Streaming Speech-to-Text API Operations: 2 Messages: 12

Channel address

/v3/ws

Operations

publish
sendClientMessage
Messages the client sends to the server.
receiveServerEvent
Events the server emits to the client.

Messages

AudioFrame
A raw binary chunk of PCM audio.
Content-Type: application/octet-stream
UpdateConfiguration
Update session parameters mid-stream.
Content-Type:
ForceEndpoint
Force the current turn to end immediately.
Content-Type:
Terminate
Politely terminate the streaming session.
Content-Type:
Begin
First event sent by the server after the session is established.
Content-Type:
Turn
A streaming transcription turn with word-level timings.
Content-Type:
SpeechStarted
Voice activity detected the start of speech.
Content-Type:
SpeakerRevision
Offline correction to a previously-emitted Turn's speaker labels.
Content-Type:
LLMGatewayResponse
Response from the optional in-band LLM gateway.
Content-Type:
Warning
Non-fatal server warning.
Content-Type:
Error
Server error event (see `StreamingErrorCodes` for the catalog).
Content-Type:
Termination
Final event acknowledging session shutdown.
Content-Type:

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.

Browse every event-driven channel on the APIs.io network or compare with the broader Agent Skill and MCP server surfaces of the same providers.

Work with this as data

Every channel here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for event channels

4 MCP tools reach this
  • find_channelsBrowse and filter every channel in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This channel 
curl "https://apis.io/api/v1/channels/v3-ws"
All event channels 
curl "https://apis.io/api/v1/channels?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.