The Webhooks feature is in the On-Premises version and it is possible to use this feature to build e.g. integration or notification system.
Full documentation of this feature can be found here.
The Webhooks feature works the same as in the SaaS version. However, there is a difference in configuration management. The configuration described here for the SaaS version may look different than what is available in the On-Premises version. The functionality has not been changed but there may be some slight differences in appearance.
The webhooks management is available for every environment in the Cloud Services Management Panel. You can find it in the Webhooks section in the details of the environment.