Google Pay service description
Now many shoppers around the world can pay with the press of a button using those payment methods saved to their Google Account.
Google Pay™ guarantees the safety of such payments as all real payment data of a user are encrypted while they are saved to the Google Account.
You must be Payment Card Industry Data Security Standard (PCI DSS) compliant and use the flow Google Pay payments with decrypted payment token data. Integration options described here, here and here are not available.
To start accepting Google Pay payments, you should accept Google Pay™ APIs Acceptable Use Policy and Google Pay API Terms of Service.