By using webhooks, you can transmit hidden data to your Payrexx hosted sales page and receive it in your system.
There are different possible solutions:
A. First option
If you don’t need to see the data in your Payrexx back office and just need the information in your webhook, you could use the following reference-ID:
Afterwards it will appear in the webhook within the following field:
B. Second option
As an alternative you can add “hidden fields” to your one page shop. Please edit your one page shop in the back office and add under form fields > new element > a hidden field:
The fields could be filled out like the following example:
C. Third option
If you don’t generate your bills with Payrexx and you would like to use a Business Paylink you can integrate the Payrexx API. Thereby you can create an “invoice” with a reference-ID, which can not be changed or manipulated by the client.
Read more about it: https://developers.payrexx.com/
D. Fourth option
Another option would be, to add an external reference to your paylink. Create a new paylink and add under "Advanced options" an external reference: