AsyncAPI channel · Azure Web PubSub · Azure Web PubSub

`/client/hubs/{hub}`

WebSocket channel between a single client and a hub on the Web PubSub service instance. Each connection belongs to exactly one hub. Messages on this channel are JSON frames defined by the `json.webpubsub.azure.v1` or `json.reliable.webpubsub.azure.v1` subprotocol. Simple WebSocket clients (no subprotocol) exchange raw text/binary frames instead and are NOT modeled here — refer to the user event ha

Open source AsyncAPI → All Azure Web PubSub channels Azure Web PubSub provider profile

Provider: Azure Web PubSub AsyncAPI: v2.6.0 Spec: Azure Web PubSub Operations: 2 Messages: 12

Channel address

/client/hubs/{hub}

Parameters

hub — Hub name. Hubs provide logical isolation within an instance.

Operations

publish

clientSend

Messages a client sends to the service over the JSON pub/sub subprotocol.

clientReceive

Messages the service sends back to the client.

Messages

joinGroup

Client asks the service to add the connection to a group.

Content-Type: application/json

leaveGroup

Client asks the service to remove the connection from a group.

Content-Type: application/json

sendToGroup

Client publishes a message to all connections in a group.

Content-Type: application/json

event

Client sends a custom user event that the service forwards to the upstream event handler as a CloudEvents request with `ce-type: azure.webpubsub.user.`.

Content-Type: application/json

ping

Client liveness check.

Content-Type: application/json

sequenceAck

Acknowledgement of a `sequenceId` delivered on an inbound message. Required for the `json.reliable.webpubsub.azure.v1` subprotocol so the service can release in-flight messages.

Content-Type: application/json

ack

Service response to a client request that carried `ackId`. Clients should inspect `success` before reading `error`.

Content-Type: application/json

messageFromGroup

Data message delivered to the client because a publisher (REST API, server SDK, or another subprotocol client) sent it to a group the client has joined.

Content-Type: application/json

messageFromServer

Data message delivered to the client because the server (REST API or server SDK) targeted this connection, the user, or all connections.

Content-Type: application/json

systemConnected

Service notifies the client that the WebSocket handshake succeeded. Reliable subprotocol additionally carries `reconnectionToken` for use on session recovery.

Content-Type: application/json

systemDisconnected

Service notifies the client that the connection was closed by the server or declined by the service.

Content-Type: application/json

pong

Service response to a `ping` request.

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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Tools for event channels

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