It would be great to send some information about the customer inside the loaded script-tag on the website. This way we can easier identify the customer, for example based on their customer_id. For example: window.Watermelon.customfields.Voornaam = 'Robin'; window.Watermelon.customfields.Achternaam = 'Dirksen'; window.Watermelon.customfields.Email = ' robin.dirksen@my-email.com '; window.Watermelon.customfields.CustomFieldForUserId = 11538;