HTML Validator 2.0FREE

Validate HTML
directly in Chrome

Check the HTML your browser renders. Find errors and warnings, inspect the markup, and revalidate — without opening DevTools.

Add to Chrome See how it works

HTML validation is free. No subscription required.

HTML Validator showing W3C Nu errors beside a sample storefront in Chrome

Current DOM

Validate the HTML your browser actually renders.

Locate Issues

Jump to the exact place in the HTML to quickly find and fix problems.

HTML Viewer

Inspect page markup and copy HTML or issue details.

Local HTML Files

Validate local files with Chrome file access enabled.

TWO VALIDATION ENGINES

Choose the right validator for your needs

Choose W3C Nu for standards-based online checking, or HTML Tidy for local offline checks.

W3C Nu

Standards-based HTML validation

Online
  • Checks modern HTML
  • Detailed errors and warnings
  • Recommended for standards checking
Validated HTML is sent to the W3C Nu service.

HTML Tidy

Basic local HTML checks

Offline
  • Runs locally in your browser
  • No HTML is sent to external validators
  • May miss or misreport modern HTML features
Best for basic offline HTML checks.

SEE IT IN ACTION

A clean and powerful workflow in Chrome

Check the HTML of any web page, view detailed results, and jump directly to the issues — all in the convenient Chrome Side Panel.

Validate in one click

Run a check and get results instantly.

Jump to the issue

Click a result to highlight the exact HTML in the page.

Inspect and copy

View the HTML, error details, and copy what you need.

HTML Validator alongside a sample outdoor gear website in Chrome

HOW IT WORKS

Get started in 3 simple steps

Pin the extension, open the Side Panel, and validate the HTML of any web page.

1

Pin the extension

Keep HTML Validator in your Chrome toolbar for quick access.

Chrome Extensions menu with HTML Validator pin highlighted
2

Open HTML Validator

Click the HTML Validator icon to open the Side Panel, then get ready to validate.

HTML Validator Side Panel on the Validate tab
3

View the results

Run the validation and review the results, including any errors or issues found.

HTML Validator Side Panel showing no HTML errors found
View Getting Started Guide

HTML validation is free. No subscription required.

READY TO VALIDATE?

Ready to validate your HTML?

Start checking HTML directly in Chrome. Free validation, no subscription required.

Add to Chrome

HTML validation is free. No subscription required.