HTML Validator

Check HTML code for syntax errors and standards compliance. Validate markup structure, detect missing tags, and ensure accessibility standards. Perfect for front-end developers.

HTML Standards Guide

✓ Best Practices

  • • Always include DOCTYPE declaration
  • • Use semantic HTML elements
  • • Include lang attribute on html element
  • • Provide alt text for images
  • • Use proper heading hierarchy (h1-h6)
  • • Include viewport meta tag
  • • Use meaningful page titles
  • • Associate labels with form inputs

✗ Common Mistakes

  • • Missing DOCTYPE declaration
  • • Unclosed or mismatched tags
  • • Missing alt attributes on images
  • • Empty or missing title elements
  • • Improper heading hierarchy
  • • Missing form labels
  • • Using deprecated HTML elements
  • • Missing meta viewport tag

Sample HTML Code

About HTML Validator

A thorough HTML validation tool that checks markup for syntax errors, standards compliance, and accessibility issues. This validator ensures your HTML follows W3C standards, identifies missing or malformed tags, and provides recommendations for improved semantic structure and accessibility.

Why use a HTML Validator?

Valid HTML is crucial for cross-browser compatibility, SEO performance, and accessibility compliance. This validator helps prevent rendering issues, improves search engine optimization, and ensures your websites work correctly across different browsers and assistive technologies, ultimately providing a better user experience.

Who is it for?

Essential for frontend developers building web applications, web designers ensuring standards compliance, QA testers validating markup quality, and content creators who need to ensure their HTML meets accessibility and SEO requirements. Perfect for anyone working with HTML code or web content.

How to use the tool

  1. Paste your HTML code into the input area or upload an HTML file
  2. Click validate to check for syntax errors and standards compliance
  3. Review detailed error and warning messages with line references
  4. Address any accessibility issues and semantic structure problems
  5. Re-validate after making corrections to ensure all issues are resolved

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