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format validator

HTML Validator (light)

Check HTML structure with HTMLHint rules—mismatched tags, casing, and basic issues—all client-side.

Results

Processing…
Status
Processing...
Details
Processing...

How to use this validator

  1. Paste the HTML snippet.
  2. Run validate to lint tag pairs/attributes.
  3. Fix reported lines (mismatched/uncased tags) and re-run.

Rules & checks

Runs HTMLHint client-side (no uploads).

Checks tag pairs, lowercase attributes, and basic structure issues.

Flags line/column of the first error and totals issues found.

Inputs explained

  • HTML content

    Paste markup snippets or templates. Keep to reasonably sized fragments for quick linting.

When to use it

  • Lint email templates before sending campaigns
  • Check CMS or WYSIWYG exports for broken tags
  • Validate snippet embeds before publishing

Common errors

  • Mismatched or unclosed tags
  • Uppercase attributes when lowercase is expected
  • Extra closing tags

Limitations

  • Lightweight HTMLHint rules; not a full W3C validator.
  • Does not fetch external assets or scripts.

Tips

  • Keep attributes lowercase to avoid warnings
  • Close non-void tags consistently to reduce rendering differences
  • Lint smaller snippets for speed; use full validators in CI for large documents

Examples

Valid

  • <div><p>Hi</p></div> -> Valid

Mismatched

  • <div><p>Hi</div> -> Flags closing tag mismatch

Deep dive

This HTML validator applies HTMLHint client-side to catch mismatched tags and casing issues before you publish.

Use it to lint snippets from CMS, WYSIWYG, or email templates without uploading markup.

FAQs

Is this a full W3C validator?
No. It applies HTMLHint rules for quick structural checks.
Do you send markup to a server?
No. Validation happens entirely in your browser.

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URL Validator

Validate HTTP/HTTPS URLs locally—parse host/path and catch malformed links before publishing or sending to APIs.

All linting happens in your browser. No data is sent, logged, or stored.

Lightweight ruleset via HTMLHint; not a full W3C validator.