CSS Validator
FreeValidate CSS stylesheets for errors and browser support
About CSS Validator
A single typo in a property name or a missing semicolon can quietly drop a whole rule block, leaving you puzzled over why a style never applied. The CSS Validator from ToolHub by Codaiman parses your stylesheet, reports syntax errors, and flags properties or values that may not behave as expected across browsers.
Paste any CSS, from a small component's styles to an entire stylesheet, and the tool checks selectors, declarations, and at-rules, pointing out mistakes and potential compatibility concerns so you can fix them before they reach production. It runs in the browser with no signup and returns results instantly, so your styles never leave your device. Free to use whenever you need a quick, reliable sanity check on your CSS.
Common uses
- Tracking down why a style rule silently fails to apply due to a typo or missing semicolon
- Checking a stylesheet for invalid properties before shipping a release
- Reviewing browser support concerns for newer CSS features in a project
- Validating CSS extracted from a build output or a third-party widget
- Cleaning up hand-written CSS during a refactor to remove errors and dead declarations
How to use
- 1
Configure options
Set your preferences using the options panel below.
- 2
Click Generate
Click the process button to generate your result instantly.
- 3
Copy or download
Copy the result to clipboard or download it directly to your device.
Why ToolHub?
- Instant error detection
- Detailed error messages
- Standards compliant
FAQ
Does it check browser support?
Yes. Alongside syntax errors, the tool flags properties and values that may have limited or inconsistent browser support.
Can it validate SCSS or LESS?
It validates standard CSS. Compile preprocessor code to plain CSS first, then validate the output here.
Will it find a single missing semicolon?
Yes, missing semicolons, unclosed braces, and similar syntax slips are reported with location detail.
Is my stylesheet uploaded?
No. Validation happens locally in your browser, so your CSS is never sent to or stored on a server.
Can I use CSS Validator on mobile?
Yes — ToolHub is fully responsive and works on iPhone, Android, tablets and all modern browsers. No app install needed.