Problem with integrating Payment provider

Hello everyone!

I’m currently facing a challenge integrating into my Bubble app, and I’m having trouble getting it to work. The API calls require HMAC, SHA256, and Base64 calculations for each request. I managed to make it work in Postman with assistance from the Payrexx support team. However, they are not familiar with and cannot guide me on the integration process. I also came across some posts suggesting to create custom plugins to handle the calculations and dynamically insert them into the API calls, but I’m unsure how to proceed with that approach.

I would greatly appreciate it if someone could assist me in getting this integration to work. Thank you in advance for any help you can provide!

Here is the screenshot from Postman with the Pre-request Script that Payrexx gave me: