DevUtilX

CSS Validator

Check your CSS for syntax errors and invalid rules. Validation runs 100% in your browser — no code leaves your machine.

Issues
Errors and warnings detected by the validator
No validation run yet. Click Validate to start.

How to Use the CSS Validator

  1. Paste your CSS code into the left editor.
  2. Click Validate to run syntax checks and rule parsing in your browser.
  3. Review the Errors (invalid rules) and Warnings (possible issues).
  4. Use the copy or download buttons to export the report.

What the validator checks

  • • Basic bracket/parenthesis balance (warnings)
  • • Missing semicolons inside rule blocks (heuristic warnings)
  • • Invalid CSS rules detected by attempting to insert each rule into the browser's stylesheet (errors)
  • • The validator is syntax-aware but not a full linter — it won't flag stylistic or best-practice issues.

💡 Privacy note: Validation is performed entirely in your browser — the code never leaves your machine.

What is a CSS Validator?

A CSS Validator is a tool that checks your Cascading Style Sheets (CSS) code for syntax errors and compliance with web standards. It helps you find mistakes like typos, incorrect property names, or invalid values, ensuring that your stylesheets are well-formed and will be correctly interpreted by web browsers.

Why Use Our CSS Validator?

  • Error Detection: Quickly identify and fix syntax errors that could break your website's layout or appearance.
  • Browser Compatibility: Writing valid CSS helps ensure that your site looks consistent across different browsers.
  • Best Practices: Encourages you to write clean, standard-compliant code, which is easier to maintain and debug.
  • Learning Tool: Helps you learn the correct CSS syntax and rules by pointing out your mistakes.

🚀 Explore More Free Developer Tools

Don’t stop here! Supercharge your workflow with our other powerful converters & formatters.

✨ CSS Formatter

Format and organize CSS code with proper structure and indentation

🎨 CSS/SCSS Minifier

Minify CSS code by removing whitespace and comments

🎨 SCSS Validator

Validate SCSS stylesheets

💡 New tools are added regularly — bookmark DevUtilsX and stay ahead!

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