A webhook posts an event to your server the moment it happens, such as a booking being made or a call ending. Each business has one webhook in Settings; automations such as Zapier create their own subscriptions through the API.
- Open Settings and choose the Developers tab. Only Owners and Admins can set up a webhook.
- Under Webhook, enter the Receiver URL: a public https address that answers with a 2xx status.
- Under Send these events, tick the events you want.
- Press Set up webhook.
- Copy the Signing secret shown under it and keep it with your receiver.
- Press Send test event. It arrives within a few seconds.
Each delivery is a POST with a harkbell-event header naming the event and a harkbell-signature header. Verify that signature before you trust the body: it is an HMAC of the raw request body using your signing secret. The developer reference has the exact recipe in Node.js, Python and PHP, the payload of every event, and the retry rules.
Manage it
- Save updates the URL or events. Turn off pauses delivery without losing the secret, and Turn on resumes it.
- Rotate secret signs deliveries with a new secret immediately; your receiver refuses them until you give it the new one.
- Remove stops events. Setting it up again gives a new signing secret.
- The pill reads On, Off, Failing or Not set up.
Respond quickly with a 2xx
A delivery that does not get a 2xx is retried for a while, and an address that keeps failing is paused and eventually switched off. Do slow work after you have acknowledged the request.
Which events can I receive?
New, moved and cancelled bookings, new callback requests, completed calls, new booking requests, and new and merged contacts. The Webhook form lists them with descriptions, and the reference has an example of each.
Does a change I make through the API trigger my webhook?
No. Contacts and callbacks written through the API never raise events, so an automation cannot trigger itself.