Payment gateway
A third-party service that processes card payments for an app or website.
Definition
Apps rarely process cards themselves. They send payments to a provider like Stripe, Adyen or PayPal. These providers have test modes with special test card numbers for approved, declined and 3-D Secure payments, which testers use instead of real cards.
In practice
Using the provider's "card declined" test number should show a clear payment error and keep the cart intact.
Learn it in context
Lessons that use this term.