Foundation · 2 min
What you need to know
When should validation show?
For simple format mistakes, validate after the field is completed or at submission. Do not show an error while a shopper is still typing a valid email or address.
What does a useful message say?
“Enter a postal code for this delivery address” is clearer than “Invalid input.” Move focus to the problem or provide an error summary so keyboard and screen-reader users can find the issue.
What happens after submission fails?
Do not silently resubmit payment. Tell the customer whether an order was placed, keep safe non-payment details, and provide a retry or support path. Check actual payment status before advising another charge.
A quick store check
Trigger one error at a time and then several together. Confirm focus, messages, preserved values and successful resubmission on a phone.
Foundation · 2 min
Frequently asked questions
Should the form clear after an error?
No. Keep entered details unless security or payment-provider rules require a particular field to be re-entered.
Where do I edit checkout error messages?
Use current checkout guidance for supported controls and reproduce the live error after publishing a change.