CSS Validator
Validate CSS syntax — unclosed braces, bad properties, bad values — with line numbers. Catch the missing } breaking layouts — local validation, free, no signup.
How to Use the CSS Validator
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Frequently Asked Questions
What errors get caught?
Unclosed braces, unknown properties (typos like colourr), invalid values, and stray semicolons — each with line numbers for instant jumps.
Browser-specific properties?
Vendor prefixes (-webkit-, -moz-) validate as known; experimental properties warn rather than error. Unknown property usually means a typo.
Validate minified CSS?
Yes — errors report by construct; beautify first for readable line numbers. Production bundles validate the same as sources.
Is my CSS uploaded?
No — validation runs locally in your browser. Code never leaves your device.
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Last updated October 2026