Payment Window

What is a payment window?

A payment window is the payment page, iframe, or inline fields provided by your payment provider (PSP) where the customer enters and confirms their card details. In ecommerce the term usually refers to the hosted solution from providers like QuickPay, Nets Easy, or Reepay — the step in checkout where the card transaction itself is handled. Card data is entered directly with the provider, not on your own server.

Why does a payment window matter?

Because card details are entered with the PSP and not in your store, a hosted payment window sharply reduces your PCI DSS responsibility — in practice often down to the light SAQ A level. The payment window is also where the 3D Secure and SCA authentication (required under PSD2) is presented to the customer. A fast, trustworthy, and reliable window is therefore critical: errors or friction here mean declined payments and lost orders at the very end of the flow.

Common use cases

• Full redirect to the provider’s page, where the customer completes payment and is sent back to the store.
• Embedded iframe in checkout, so the customer stays on your site while the card fields are hosted by the PSP.
• Inline hosted fields (tokenization) that look like the store’s own fields but are secured by the provider.
• 3D Secure/SCA authentication, where the customer’s bank verifies the payment inside the window.
• Troubleshooting declined cards, timeouts, or a missing return callback from the payment provider.

Shopify perspective

If you use Shopify Payments, the card fields are handled by Shopify itself through tokenized iframes and cannot be freely custom-coded for PCI compliance reasons. If you choose a third-party payment gateway, payment happens either in an embedded window or via redirect to the provider. Always test the payment window with real test cards and a 3D Secure flow, and confirm the customer is returned correctly to the order confirmation, so you don’t lose payments to a broken callback.