Cart and Checkout Validation error messages not displaying during Google Pay accelerated checkout

Functions
1

Hi everyone,

I’ve encountered an issue with the Cart and Checkout Validation API when a buyer uses the Google Pay accelerated checkout.

  • The validation function runs correctly.

  • Checkout is blocked as expected, but no error message is displayed to the buyer.

  • The validation target is $.cart.

  • During regular checkout, the validation error message appears as expected.

Expected

The buyer should see the validation message when the checkout is blocked, even when using Google Pay.

Actual

Google Pay checkout is blocked silently — no visible error message is shown.

Environment

  • Function type: cart_and_checkout_validation

  • Target: $.cart

  • Accelerated checkout: Google Pay

  • Regular checkout: Works correctly

Has anyone else seen this behavior, or is this a known limitation?

Would appreciate any confirmation or suggested workarounds. Thanks!

2

I’ve run into this too.

Your function is working, the wallet flow just doesn’t render merchant-supplied validation messages. With accelerated checkouts (Google Pay, Apple Pay, Shop Pay), validations run and can block the transaction, but the message isn’t shown inside the wallet sheet.

The buyer is bounced back to checkout without inline feedback from the wallet UI (Cart and Checkout Validation Function API)

Two practical workarounds I’ve used: surface the rule at checkout with a Checkout UI extension banner so the message is immediately visible when the buyer returns from Google Pay; or, if the rule relates to address, shipping method, or line items, scope the validation to a more specific target so the message appears on the corresponding checkout step rather than relying on the wallet sheet.

You can add a persistent banner or inline notice with Checkout UI Extensions, which is the only reliable way to guarantee a visible message post-wallet (Checkout UI extensions). If you share your rule and message payload, I’m happy to suggest the exact target and UI banner placement.

3

This is a bug and we are able to reproduce - thank you for the detailed report. We are tracking the issue on our end.

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