[#1488] Prefilling a booking field with tracking value

Migrated from Redmine #1488 | Author: Kenneth Olsen
Status: New | Priority: High, I’m very impatient | Created: 2025-11-12


We are integrating Adtraction affiliate tracking with our SimplyBook setup and have a follow-up question regarding the booking form.

We need to store a tracking value called at_gd for each booking. This value is generated when a user visits our website via an Adtraction link and is stored in a first-party cookie on our domain.

When the user opens our booking form (which is embedded on our WordPress site via an iFrame), we would like to prefill a hidden custom field in SimplyBook with this at_gd value — for example by passing it as a query parameter in the iFrame URL.

Example:
https://crosseyes.simplybook.it/v2/#book?at_gd=8F9A07E32F65C7FC95796D166E9797FEE424111B

Could you please confirm:

Whether SimplyBook allows prefilling custom fields or intake fields using URL parameters (like ?at_gd=value)?

If not directly via URL, is there another way (e.g., via JavaScript API or widget configuration) to pass a tracking value into the booking form so it becomes part of the booking data?

Whether that value would also be included in your webhook/callback payload when a booking is created?

For context, our setup:

Website: WordPress

Booking form: standard SimplyBook booking widget embedded via iFrame

Tracking partner: Adtraction (server-to-server conversion tracking)

This information is essential to complete the integration, since the at_gd value needs to be included with each booking in order to report conversions correctly.

Thank you very much for your help!