WCAG 2.1 SC 3.3.6: Error Prevention (All) (Level AAA)
3.3.6 Error Prevention (All) (Level AAA) — what it requires, a common failure example, and how to fix it. Part of WCAG 2.1's 3.3 Input Assistance guideline under the Understandable principle.
WCAG 2.1 guidelines hub → Understandable → 3.3 Input Assistance
3.3.6 Error Prevention (All) (Level AAA)
Input Assistance is the guideline most directly relevant to checkout and account forms — it governs whether people can tell what a field wants, whether errors are described clearly, and whether a costly mistake (an accidental purchase, a wrong shipping address) can be caught before it’s final.
This page is educational technical reference material, not legal advice. Meeting WCAG 2.1 does not by itself determine legal compliance with the ADA or any other law — consult qualified counsel for legal risk questions.
Plain-language explanation: This extends 3.3.4 beyond legal/financial transactions to all user-submitted forms — any submission should be reversible, checked, or confirmed.
Common failure: A “delete saved address” action removes the address immediately with no confirmation step and no undo.
Remediation: Add a confirmation step (“Are you sure you want to delete this address?”) or a short undo window for any user-submitted change, not only checkout-related ones.
In this guideline — 3.3 Input Assistance: 3.3.1 Error Identification (A) · 3.3.2 Labels or Instructions (A) · 3.3.3 Error Suggestion (AA) · 3.3.4 Error Prevention (Legal, Financial, Data) (AA) · 3.3.5 Help (AAA) · 3.3.6 Error Prevention (All) (AAA)
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This page is educational content about technical accessibility practice, not legal advice. Meeting WCAG 2.1 does not guarantee legal compliance with the ADA or any other law. Consult qualified counsel for legal risk questions.
This page was drafted with AI assistance and reviewed by a person for accuracy before publication.