Agent Skills: Google Pay Knowledge Patch

Google Pay Knowledge Patch

Use this skill when implementing or reviewing Google Pay Web merchant integrations that involve payment-sheet behavior, callback intents, address formats, card or payment-method configuration, test cards, button styling, content security policy nonces, or direct-integration signing keys.

How to use this skill

1. Start with the quick reference for the relevant integration surface.
2. Open the indexed reference file for the complete guidance on that topic.
3. Preserve the documented property names, enum values, labels, and scope.
4. Do not infer unlisted configuration values or behavior.

Reference index

| Reference | Topics | | --- | --- | | Web configuration and testing | CSP nonces, supported button borders, multi-market gateway test cards | | Addresses and checkout | ISO 3166 administrative areas, checkout labels, payment-sheet promo codes | | Payment methods and processing | Card funding sources, INTERAC, PayPal, callback parity, ECv2 direct-integration keys |

Quick reference

Apply a CSP nonce to injected elements

PaymentOptions accepts a nonce. When it is present, the CSP nonce is applied to every dynamically injected <style> and <script> element.

const paymentOptions = {
  nonce: cspNonce,
};

See Web configuration and testing for the web-configuration details.

Request full ISO 3166 administrative-area data

Set BillingAddressParameters.format to FULL-ISO3166.

const billingAddressParameters = {
  format: "FULL-ISO3166",
};

ShippingAddressParameters also has a format property. Returned Address and IntermediateAddress objects include iso3166AdministrativeArea.

See Addresses and checkout for the address-format details.

Select the payment-sheet checkout label

Set TransactionInfo.checkoutOption according to the label the payment sheet should display.

| Value | Displayed label | | --- | --- | | DEFAULT | “Continue” | | CONTINUE_TO_REVIEW | “Review Order” | | COMPLETE_IMMEDIATE_PURCHASE | “Pay” |

const transactionInfo = {
  checkoutOption: "CONTINUE_TO_REVIEW",
};

See Addresses and checkout for related payment-sheet guidance.

Read the selected card's funding source

CardInfo.cardFundingSource reports one of these values:

| Value | | --- | | UNKNOWN | | CREDIT | | DEBIT | | PREPAID |

The value lets pricing, discount, or surcharge logic distinguish the selected card's underlying funding type.

See Payment methods and processing for card and payment-method details.

Request INTERAC

CardParameters.allowedCardNetworks supports INTERAC.

const cardParameters = {
  allowedCardNetworks: ["INTERAC"],
};

Request PayPal

The type property of a PaymentMethod request supports PayPal as a payment method.

See Payment methods and processing for both request options.

Use callback integrations with payment-sheet feature parity

Web integrations using authorizePayments or Dynamic Price Updates callback intents receive the non-callback payment-sheet UX except where incompatible, such as OFFER callbacks.

Liability shift and processor test cards are also available to these callback integrations.

See Payment methods and processing for the callback-integration scope.

Manage ECv2 direct-integration keys

For DIRECT integrations, ECv2 permits a static, long-lived Google signing key that only needs updating every ten years.

See Payment methods and processing for the direct-integration guidance.

Configure a supported button border

ButtonOptions passed to createButton() accepts borderButtonType. This exposes border selection through the supported button configuration.

See Web configuration and testing for button configuration.

Display and update promo codes

The OfferInfo API lets merchants update and display promo codes on the payment sheet.

See Addresses and checkout for payment-sheet offer guidance.

Test billing addresses across markets

Gateway test cards in the TEST environment support billing addresses from 27 markets rather than only the US. This enables country-specific end-to-end billing tests.

Supported examples include:

• UK
• France
• Germany
• Spain
• Japan
• Hong Kong
• Brazil

See Web configuration and testing for the testing details.

Integration review checklist

• If injected styles or scripts must carry a CSP nonce, provide PaymentOptions.nonce.
• If administrative-area values need ISO 3166 formatting, use FULL-ISO3166 and read iso3166AdministrativeArea from returned address objects.
• If the payment-sheet button label matters, select the matching TransactionInfo.checkoutOption value.
• If pricing, discount, or surcharge logic depends on funding type, read CardInfo.cardFundingSource.
• If the request needs the INTERAC network, include INTERAC in allowedCardNetworks.
• If the payment method is PayPal, use the supported PaymentMethod request type.
• If the integration uses authorizePayments or Dynamic Price Updates callback intents, account for the stated callback feature parity and the OFFER incompatibility example.
• If the integration is DIRECT, account for the ECv2 static signing-key update interval.
• If the button needs a supported border selection, use borderButtonType in the ButtonOptions passed to createButton().
• If promo codes appear on the payment sheet, use OfferInfo to update and display them.
• If billing behavior varies by country, gateway test cards in TEST support billing addresses across 27 markets.