Nu Html Checker
The W3C checker validates modern HTML and reports structural mistakes such as invalid nesting, duplicate identifiers, and unsupported attributes.
Limitations: Valid HTML is not automatically accessible, and some reported messages are technical. Use it beside accessibility testing rather than as an accessibility score.
Why it is useful
The W3C checker validates modern HTML and reports structural mistakes such as invalid nesting, duplicate identifiers, and unsupported attributes. This resource is especially useful for Finding markup errors that can interfere with browsers and assistive technology. Review the current instructions and limitations from World Wide Web Consortium before relying on it for important work.
Limitations
Valid HTML is not automatically accessible, and some reported messages are technical. Use it beside accessibility testing rather than as an accessibility score.