Follow the instructions in Request a signature for the Payment Page from Zuora . Because the Client-side HPM Parameter Validation feature is enabled, Zuora will validate the additional fields in the request by comparing them with the values specified in the digital signature.

Here are two request examples for the Generate RSA signature REST API operation.

{
    "uri":"https://sandbox.na.zuora.com/apps/Pu...tedPageLite.do",
    "method":"POST",
    "pageId":"test808145b3bf9d0145b3c6812b0008",
    "paymentGateway":"Adyen",
    "authroizationAmount":"100",
    "currency":"PHP",
    "accountId":"test808145b3bf9d0145b3c6812b0008"
}

{
    "uri":"https://sandbox.na.zuora.com/apps/Pu...tedPageLite.do",
    "method":"POST",
    "pageId":"test808145b3bf9d0145b3c6812b0008",
    "paymentGateway":"Adyen",
    "accountId":"test808145b3bf9d0145b3c6812b0008"
}