Google Pay Express Checkout

Google Pay is a single-call express checkout. The wallet ceremony happens entirely client-side in the Google Pay sheet; there is no start or authorize call on the Firmly API. Once the sheet returns a payment token or nonce, hand it to:

• Complete Order — place the order with the Google Pay credential

​​ Checking availability

Google Pay is enabled per merchant. Any cart response lists what the merchant supports:

"payment_method_options": [
  { "type": "CreditCard", "wallet": "user" },
  { "type": "GooglePay", "wallet": "google" }
]

If no "type": "GooglePay" entry is present, do not render the Google Pay button — the endpoint returns 404 GatewayNotFound.

The merchant’s Google Pay configuration arrives on the cart as shop_properties.google_pay — see Get Cart for the full field list.