Wix billing events are fired on your site's backend when certain events occur related to billing. You can write event handlers that react to these events. Event handler functions receive data that corresponds to the event that fired. Use event handlers to create custom responses to contact events.
To add a billing event handler, add an events.js file to the Backend section of your site if one does not already exist. All event handler functions for your site are defined in this file.
Event handler functions are defined using the following pattern:
For example, an event handler that handles invoice creation looks like this:
Note: Backend events don't work when previewing your site.