Can I validate minified CSS?

Yes, the validator works with both human-readable and minified CSS. It parses the code structure regardless of formatting.

Does it support CSS3 and modern properties?

Yes, it supports CSS3, CSS Grid, Flexbox, CSS Variables (custom properties), CSS Animations, and modern selectors. The property database is regularly updated.

CSS Validator - Free Online CSS Syntax Checker & Linter

Enter CSS code:

Validation Results

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How to Use CSS Validator

Paste your CSS code into the text area above
Click "Validate" to check for errors and warnings
Review the error list with line numbers and descriptions
Fix the highlighted issues and re-validate
Use "Load Sample" to try with example CSS code

What CSS Validator Checks

✅ Missing or mismatched brackets { } and parentheses
✅ Missing semicolons between declarations
✅ Invalid CSS property names
✅ Incorrect property values (e.g. wrong color format, invalid units)
✅ Duplicate selectors and properties
✅ Unknown pseudo-classes and pseudo-elements
⚠️ Browser compatibility warnings for modern features
⚠️ Unusual vendor prefix usage

Frequently Asked Questions

Is this CSS Validator free to use?

Yes, it is completely free with no registration, login, or usage limits. Use it as many times as you need for both personal and commercial projects.

Does the validator upload my CSS code?

No. All validation happens locally in your browser using JavaScript. Your CSS code never leaves your device — this makes it safe for validating proprietary or confidential stylesheets.

What types of errors can it detect?

The validator checks for: missing or mismatched brackets/braces, invalid property names, incorrect property values, missing semicolons, duplicate selectors, unknown pseudo-classes/elements, @-rule errors (like @import, @media), and common browser compatibility issues.

Does it work with minified CSS?

Yes, it works with both readable and minified CSS. The parser handles code regardless of formatting or whitespace. Results may show fewer errors with well-formed minified CSS since minified code typically has fewer syntax issues.

Does it support modern CSS features?

Yes, it supports CSS3, CSS Grid, Flexbox, CSS Custom Properties (variables), CSS Animations and Keyframes, Container Queries, :has() selector, and modern pseudo-classes. The property database is updated to reflect current CSS specifications.