Hi @Abdul_Waheed,
From the error response, this may be due to a couple things:
- All spaces and other whitespace outside of strings must be removed.
- Numbers should be sent in strings, not as integers/numbers.
Here are some resources that may help:
- Rapyd API Request Signatures and How to Calculate
- Verify Webhook Signature? - #2 by Minh_Nguy_n_Van
- How to verify Webhook Signature with PHP script
- https://youtu.be/yL5TK4JfP7s
I would also take a look around your body and and how it may not be parsed correctly.