salesjet-webhook.js

/* on the headers add "Content/Type: application/json" and "Authorization [api_key] */
{
    "event_name": event_name, 
    "contact": { 
       "email": email, 
        "first_name": first_name,
        "last_name": last_name,
        "phone_number": phone_number,
        "custom_attributes": {
            /* use uuids of the custom attribute here */
            "7b438eca-d73b-ea11-a9a8-be86afc8905f": value
        } 
    }
}