A webhook (also called a web callback or HTTP push API) is a way for an app like Cheqroom to provide other applications with real-time information. 

A webhook delivers data to other applications as it happens, meaning you get data immediately. Unlike typical APIs where you would need to poll for data very frequently in order to get it real-time. This makes webhooks much more efficient for both provider and consumer.

item.create Triggered when an Item was created
item.update Triggered when a system field on an Item was updated
item.duplicate Triggered when an Item was created by duplicating another Item
item.setfield Triggered when a custom field on Item was updated
item.clearfield Triggered when a custom field on an Item was cleared
item.setflag  Triggered when an Item flag was just updated
item.clearflag  Triggered when an Item flag was just cleared

item.expire Triggered when an Item is expired

item.undoexpire Triggered when an Item is unexpired

item.changelocation Triggered when an Item location was just updated

item.addcomment Triggered when an Item comment was just added

item.takecustody Triggered when a contact takes custody of an Item

item.transfercustody Triggered when Item custody is transfered to another contact

item.releasecustody Triggered when a contact releases custody of an Item

contact.create  Triggered when a Contact was just created
contact.update  Triggered when a Contact was just updated

contact.addcomment Triggered when a Contact comment was just added

contact.block Triggered when a Contact was blocked

contact.undoblock Triggered when a Contact was unblocked

reservation.reserve Triggered when a Reservation was just made
reservation.cancel  Triggered when a Reservation was just cancelled
reservation.due_in_1_hour  Triggered when a Reservation is due for pickup in 1 hour
reservation.due_in_1_day  Triggered when a Reservation is due for pickup in 1 day
reservation.overdue_1_hour  Triggered when a Reservation was due for pickup 1 ago
reservation.overdue_1_day Triggered when a Reservation was due for pickup 1 day ago

order.checkout  Triggered when a Check-out was just checked out
order.checkin  Triggered when a Check-out was just (partially) checked in
order.undocheckout  Triggered when a Check-out was undone
order.due_in_1_hour  Triggered when a Check-out is due in 1 hour
order.due_in_1_day  Triggered when a Check-out is due in 1 day
order.overdue_1_hour  Triggered when a Check-out was due 1 hour ago
order.overdue_1_day  Triggered when a Check-out was due 1 day ago'}

All webhook POST requests will include an X-CHEQROOM-Signature header, whose value will contain an HMAC SHA256 hex digest of the webhook payload, using the signing secret as the key.

You should compute the signature of the payload using the same shared secret in your code to verify that the webhook was triggered by Cheqroom.

As of now, Cheqroom doesn't support incoming webhooks.