HTML Validator

Check your HTML code for common errors. Detect unclosed tags, duplicate IDs, missing alt attributes, and deprecated elements.

Validate HTML

Paste your HTML code below

How It Works

  1. Paste your HTML code
  2. Click Validate
  3. Review errors and warnings

What It Checks

  • Unclosed or mismatched tags
  • Duplicate element IDs
  • Missing alt on images
  • Deprecated HTML elements

Your text is processed entirely inside your browser.

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Frequently Asked Questions

What does the HTML validator check for?

It checks for unclosed tags, duplicate IDs, missing alt attributes on images, and deprecated HTML tags.

How accurate is the validator?

It performs basic static analysis to catch common HTML errors. It is not a full W3C validator but catches most common issues.

Is my HTML uploaded to a server?

No. All processing happens entirely in your browser. Your code never leaves your device.

What are deprecated HTML tags?

Deprecated tags are old HTML elements like font, center, and marquee that are no longer recommended for use in modern HTML.

Read Guide: HTML Validator Guide