Quick answer. A webhook is the HTTPS endpoint where the RCS platform sends you real-time events: inbound user messages, taps on suggested replies/actions (with their postbackData), delivery and read receipts, typing indicators, and opt-in/opt-out (subscribe/unsubscribe) events. You register the URL with your provider, verify incoming requests (signature/token), acknowledge with a 200, and process the payload. This is how two-way RCS and accurate delivery analytics work.
A simplified inbound payload when a user taps a suggested reply (postbackData lets you map the tap to intent):
{
"senderPhoneNumber": "+14155550123",
"messageId": "abc-123",
"suggestionResponse": {
"postbackData": "confirm_appt_1043",
"text": "Confirm"
},
"sendTime": "2026-06-08T17:40:00Z"
}
Always verify the request is genuinely from your provider before acting on it, and respond quickly with a 200 so events aren’t retried unnecessarily.