HTML Validator

Free online HTML validator. Check HTML markup against W3C standards and detect errors, warnings, and accessibility issues. Instant client-side validation.

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Validation Results

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Frequently Asked Questions

Does this follow W3C standards?

Yes. The HTML validator checks your markup against W3C HTML5 standards and reports spec violations.

Does it check for accessibility issues?

The validator reports structural HTML issues that impact accessibility, such as missing alt attributes and invalid ARIA roles.