The most expensive email in e-commerce is the one nobody validates
The customer typed gmial.com. Checkout succeeded, payment cleared, the order shipped — and they have received nothing. So they email support asking whether the order went through, or they file a chargeback, because as far as they can tell it did not.
Every downstream message — shipping, delivery, review request, the entire post-purchase lifecycle you built — routes through an address typed once, on a phone, at speed.
How it works
- 1Validate on blur, before the pay button. Never after payment.
- 2If an address looks like a typo, have your checkout suggest a fix. Do not block. A hard block on a checkout field costs you the order.
- 3Block only clear invalids and disposables, and let everything else through.
Rules for checkout specifically
- Never block on timeout. A verification hiccup must never cost a sale. Fail open, always.
- Suggest, do not reject. “Did you mean priya@gmail.com?” as a one-tap fix recovers both the order and the customer's inbox.
- Guest checkout is where this pays. No account means no second chance to reach them.
- Validate before payment. Correcting an address after the charge means a support ticket either way.