Run every payment method you plan to offer through test mode before you switch to live keys. Use sandbox keys and Blink's test details, and check each order in both WooCommerce and the Blink Portal.
Set up test mode
Sign up for a sandbox account or contact integrationsupport@blinkpayment.co.uk if you don't have one.
In the Blink settings, enter your sandbox keys in Test API Key and Test Secret Key.
Tick Enable Test Mode and save.
Get test card and bank details from Test credentials. See also Navigating sandbox accounts.
Checklist
Card payment succeeds and the order moves to Processing in WooCommerce
Card payment is declined, the customer sees a reason, and can try again
3D Secure challenge completes
Google Pay, Apple Pay, Open Banking and Direct Debit each complete, for the methods you offer
Each transaction appears in the Blink Portal
A refund made from WooCommerce shows in the Blink Portal, and a full refund marks the order Refunded
If you use pre-authorisation, the order is On hold after checkout and moves to Processing once captured
Checkout works on mobile, and with both Direct and Hosted if you may switch
Customer and admin order emails arrive once, not twice
Go live
When the checklist passes, follow Going live on the Configure page: add live keys, untick Enable Test Mode, and place one real low-value order.
Apple Pay depends on the device. Test it on an iPhone or iPad. On a Windows computer, Apple Pay asks the customer to scan a code with an iPhone running a recent version of iOS.