Upsource checks for new revisions in the repository at the interval which you specify when creating or editing the project.
With a web hook enabled, your VCS will notify Upsource about new revisions, allowing it to record and display these revisions the moment they are made.
In addition to the benefits of real-time updates, web hooks reduce the frequency of calls to your VCS service, effectively reducing the overall payload.
To enable a web hook for a specific project
Go to project / web hooks settings of your VCS service and specify a notification URL:
You can find the project ID on the Edit page of your project in Upsource.
Specify either POST or GET request to be sent for notification. Other settings are irrelevant.
To reduce the payload on your VCS, in the Upsource Create/Edit project form, set the check for changes interval to 30 minutes or more.