op
: Operation type, for example subscribe
, unsubscribe
, or ping
data
(optional): Parameters specific to an operation
id
(optional): The request ID, an arbitrary integer passed to link requests with responses
data
: The JSON payload of the response or the channel message
error
(optional): The error message returned if an error occurred
id
(optional): The ID of the corresponding request, if it is provided
channel
(optional): The channel for the sent message, only added to the response when there is a response on the channel