To access project webhooks, in the Backlog project, go to Project Settings > Integrations and select Webhook > Settings.
A list of existing webhooks, if any, will be shown.
To add a new webhook, click on Add Webhook at the webhook settings page.
Enter a name for the Webhook, paste the external URL in the Webhook URL field for sending Backlog events data, and select the events to notify.
To send test data, click on the Execute button after choosing the event in the dropdown menu. The sent data and results can be checked in the Webhook sent log.
Click on Add Webhook to submit. The new webhook will be added to the webhook settings page.