## How it works

Exercise successful payments and failures before launch. Every scenario should verify both the checkout behavior and the corresponding backend order state.

## Implementation

Use the processor's sandbox credentials and test cards. Cover success, decline, 3DS, an abandoned redirect, expiry, delayed or duplicate webhooks, refunds and capture where applicable. Confirm that test events cannot trigger real fulfilment. Check the iframe on mobile and desktop, including wallet popups. Retrying a network timeout must not create a second order or payment. Retain test IDs and expected results without storing card details.

## Related guides

- [Test and live payments](/docs/general/test-and-live/)