Set up SCA/authentication flows

Enable the SCA authentication flow for EU cards on the checkout path. Require two-factor challenge for payments over €250 and for any new card save. Notify the product manager, Elena, and the head of engineering, Jamal, when the change goes live and include a short test plan showing a successful challenge and a fallback flow for failed authentications.

Before I flip on stronger authentication for EU customers, make it straightforward for product and support to accept. Show the UX hit in abandonment for a 2FA requirement at the €250 threshold, surface which countries will see the challenge most often, and flag any payment methods that cannot perform SCA. Offer one alternative configuration that lowers abandonment while preserving liability shift.

I enabled the stricter authentication rules for EU cards yesterday and Elena reports a sudden drop in conversion on Friday’s campaign. I can’t tell whether the decline is because the challenge is failing for certain banks, the threshold is too low, or the payment methods are incompatible. What is the most likely cause and what quick test should I run now that will tell me which one it is?

Every time we adjust authentication rules we see unexpected falls in completed payments and finger-pointing between product and engineering. It costs sales and stretches support. Which recurring decision or measurement are we skipping that leads to these surprises, and what single habit change would prevent future rollouts from breaking conversion?