WCAG – 3.3.4 Error Prevention (Legal, Financial, Data) (Level AA)

3.3.4 Error Prevention (Legal, Financial, Data): For Web pages that cause legal commitments or financial transactions for the user to occur, that modify or delete user-controllable data in data storage systems, or that submit user test responses, at least one of the following is true: (Level AA)

  • Reversible: Submissions are reversible.
  • Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
  • Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

This applies to native apps by replacing “Web pages” with “screens”.


  • When data is submitted leading to a legal commitment, financial transaction, or an update to personal data, a review page is presented that allows the user to review, correct, and confirm the information they have entered.

Why is it important?

This provides safeguards to prevent people with disabilities, and indeed all users, from making avoidable mistakes.


If users are making a legal commitment, a financial transaction or updating personal data, give them a way to review and check that the information they’ve entered before submitting it.
When completion of a form causes a legal commitment, triggers a financial transaction, or gives consent for personal data to be updated, the user must be able to review, correct, and confirm that the information they have entered is correct, or they must be able to reverse the decision.

Common mistakes

An online shop where order details are not displayed again for confirmation just before users’ commit the transaction.


  1. Design pattern: Let the user review and correct information before submission
  2. Design pattern: Requesting confirmation to continue with their selected action
  3. Accessibility Guidelines- Github.io