CSS Checker
Find and fix stylesheet errors instantly. Right inside your browser — no need to copy-paste code into external websites.
CSS Checker is a lightweight browser extension that helps developers and designers instantly find and fix errors in their stylesheets. Whether you are debugging a complex layout or validating a simple page, this css checker tool saves you hours of manual inspection. It works right inside your browser - no need to copy-paste code into external websites or switch between tabs.
Tired of Hidden Stylesheet Errors?
If you write styles regularly, you know how frustrating hidden errors can be. A missing semicolon, an invalid property, or a broken selector can silently break your layout. That is exactly why a reliable css validator and css checker matters. It scans your stylesheets in real time and highlights every issue so you can fix it on the spot 🔍
Validation Flow in 5 Steps
Open Any Webpage
Open any webpage and click the extension icon.
Scan Automatically
The css code checker scans all stylesheets automatically.
Review Report
Review errors, warnings, and suggestions in the report panel.
Audit Contrast
Switch to the contrast tab to audit accessibility.
Fix and Re-validate
Fix your code and re-validate with one click.
What Makes This CSS Checker Stand Out
Instant CSS Validation
Instant css validator stylesheet validation on the current page.
Detailed Error Reports
Detailed error and warning reports with line numbers.
Contrast Checker
Built-in css color contrast checker for accessibility.
CSS & XPath Checker
Support for css and xpath checker functionality.
Compatibility Checker
css compatibility checker for cross-browser support.
One-Click Re-scan
One-click re-scan after changes.
The extension is not just a css syntax checker - it is a full-featured css validator toolkit for anyone who works with stylesheets daily. It parses your code, detects problems, and provides clear suggestions. From typos in property names to incorrect value formats, this css checker catches issues before your users notice them.
Many developers rely on external validation websites, but switching tabs and pasting code is slow. This css checker brings everything directly into your dev tools - right where you need it
The compatibility feature is especially useful when you support multiple browsers. It flags properties that may not work in older versions of Chrome, Firefox, Safari, or Edge so you can add fallbacks before users encounter visual bugs 🔒
Who Can Benefit From This CSS Checker Tool
Frontend Developers
Frontend developers debugging production stylesheets.
QA Engineers
QA engineers running cross-browser compatibility audits.
Designers
Designers verifying their styles match the intended design.
Students
Students learning web development who want instant feedback.
Accessibility Specialists
Accessibility specialists checking contrast ratios to meet WCAG standards.
One of the most popular features is the built-in css color contrast checker. Poor contrast between text and background is a common accessibility violation. This css validator evaluates your color pairs against WCAG 2.1 guidelines and flags any combination that does not meet AA or AAA thresholds. Accessible design starts with proper contrast verification 🎨
By the Numbers
How the CSS Validator Works
It detects all linked and inline stylesheets on the active page and parses each one for issues:
Detects Stylesheets
It detects all linked and inline stylesheets on the active page.
Parses and Checks
It parses each stylesheet and checks for syntax errors and unknown properties.
Groups Results
It groups results by file so you can navigate large projects easily.
Highlights Findings
The css checker highlights relevant findings directly in the report panel.
Common Questions
Does it support modern properties?
Yes — the css syntax checker recognizes the latest specs including custom properties, grid, and flexbox shorthand.
Can I use it as a css and xpath checker?
Absolutely — the extension includes xpath validation alongside stylesheet analysis.
Does it work on local files?
Yes, enable file access in your browser settings.
How does contrast checking work?
This css validator evaluates your color pairs against WCAG 2.1 guidelines and flags any combination that does not meet AA or AAA thresholds.
Is the extension safe?
Yes! We only read page CSS and DOM properties to help you check styles. See our Privacy Policy for details.
Whether you need a quick scan or a thorough css validator for production, CSS Checker adapts to your workflow.
Key features at a glance:
- Real-time css checker validation with detailed error reports
- Built-in css validator following W3C specifications
- Color contrast checker for WCAG compliance
- XPath and selector validation built in
- css compatibility checker for cross-browser support
- css content checker to audit property usage across stylesheets
Stop Wasting Time Hunting for Stylesheet Bugs
With a dedicated css error checker and a reliable css contrast checker all in one extension, you have everything you need to write clean, accessible, and error-free stylesheets ✅
Install CSS Checker TodayFree, fast, and built by developers who understand stylesheet pain.