DevUtilX

HTML Validator — Check Markup & Accessibility

Paste HTML markup and run quick validation checks for best practices, accessibility, and common issues.

Run validation to see issues, counts, and recommendations. The validator detects accessibility and common HTML problems like missing alt, duplicate id, inline event handlers, and more.

How to Use the HTML Validator

  1. Paste your HTML markup in the left editor.
  2. Click Validate to run quick checks for accessibility and common issues.
  3. Review the categorized issues (Errors, Warnings, Info) on the right panel.
  4. Copy or download the JSON report for CI or sharing with teammates.

What this validator checks

  • • Presence of DOCTYPE and lang on <html>.
  • • Missing or empty <title> tag.
  • • Images missing alt attributes (accessibility).
  • • Anchor target="_blank" missing rel security attributes.
  • • Duplicate IDs, inline event handlers, deprecated tags, and large inline scripts/styles.

⚠️ Important: This is a quick, client-side checker for common issues. For full standard compliance and spec-level validation, use the W3C Validator or server-side linters.

💡 Pro Tip: Use this tool to catch accessibility and common markup issues early in development. Keep formatted source for development and use validated/minified output for production workflows.