You joined a private channel
{
"type": "group_joined",
"channel": {
…
}
}
The group_joined event is sent to all connections for a user when that user
joins a private channel.
The channel value is the string identifier for the private channel.
In addition to this message, all existing members of
the private channel will receive a group_join message event.
When an event occurs, we will send an HTTP POST request to your Request URL. The outer payload is uniform across all Events API methods, and contains fields like team_id and event. Learn more