API channel
The API channel is the escape hatch: when a channel we do not support matters to your business, you can push its messages in and read replies out, and everything else in the product treats it as a normal conversation.
You supply:
your own integration code.
What the API channel carries
Messages in, replies out
Your code creates contacts and conversations and posts incoming messages. Outgoing replies reach you through a signed webhook, so no polling is required.
It behaves like a real channel
Assignment, labels, private notes, canned responses, automation rules and reports all work on an API conversation, because it is the same conversation model as the rest.
Documented and versioned
The REST API ships an OpenAPI specification with three authentication schemes, and outbound webhooks are signed so you can verify what reached you.
Worth knowing
This channel is a building block, not a finished integration: what the customer sees on the other end is your code's responsibility.