GCash: offer the app redirect on mobile instead of a QR code

Request

On mobile, GCash checkout renders only a QR code. A buyer on their phone cannot scan a QR displayed on that same phone, so the payment is a dead end unless they have a second device.

GCash supports a mobile web flow that redirects the buyer into the GCash app and back to the merchant on completion. We should use that flow when the buyer is on mobile, and keep the QR for desktop.

Evidence

A merchant selling into the Philippines recorded 9 failures against 1 success on GCash since 17 October, all AUTHENTICATION_FAILURE, all from PH. Their card traffic from other markets over the same period was healthy, so the failure is specific to this flow rather than to their integration.

Business: bus_0NpZxKXpSNCvqRVKHQYGI

Why it matters

GCash is the default way to pay online in the Philippines and card penetration there is low. A mobile checkout that only offers an unscannable QR effectively closes that market to merchants who enable it.

Asked for

Detect mobile and use the GCash app redirect flow, falling back to the QR code on desktop.