How to find HMAC in FirstData/Payeezy ?
In your FirstData / Payeezy admin console navigate to Terminals -> ECOMM Terminal -> API Access
If the ‘Request URI’ is higher than v9, i.e. ‘/transaction/v12’, you need to check ‘Enable HMAC’ on Nexus and enter the Key ID & HMAC Key. You can get this information from the same ‘API Access’ screen: