A named Ably channel. Channels are identified by an arbitrary string name
and may live inside a namespace (e.g. `chat:room42`). Clients ATTACH to
a channel before publishing or subscribing, and DETACH when finished.
The channel address travels in the `channel` field of every ProtocolMessage
for actions ATTACH, ATTACHED, DETACH, DETACHED, MESSAGE, PRESENCE, SYNC.
Send ATTACH ProtocolMessage to begin pub/sub on a channel.
send
detachChannel
Send DETACH ProtocolMessage to leave a channel.
send
publishMessage
Publish a MESSAGE ProtocolMessage to a channel.
receive
subscribeChannel
Receive MESSAGE / PRESENCE / ATTACHED / DETACHED / SYNC / ERROR frames for a channel.
send
enterPresence
Send PRESENCE ProtocolMessage to enter, update, or leave a channel's presence set.
Messages
attach
Client request to attach to a channel.
Content-Type:
attached
Server confirmation that the channel is attached.
Content-Type:
detach
DETACH
Content-Type:
detached
DETACHED
Content-Type:
message
Carries one or more user-published Message objects on a channel.
Content-Type:
presence
Carries one or more PresenceMessage objects. Action enum:
0 ABSENT, 1 PRESENT, 2 ENTER, 3 LEAVE, 4 UPDATE.
Content-Type:
sync
Presence set synchronization frames.
Content-Type:
error
Protocol-level or channel-scoped error.
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.