All HTML check processing is performed locally, so you can use it with confidence. 2025/08/30 Update!
*If you choose "Check from URL", PHP will only be used when fetching the source (no data is stored at all).
Please also try the Google Chrome extension "HTML Tag Unclosed Checker"
A bookmarklet is also available
🔥 We’re currently testing a new version that checks tags with even greater accuracy. Please try it below.
Switch to the new version (you can switch back anytime)
*If you choose "Check from URL", PHP will only be used when fetching the source (no data is stored at all).
Please also try the Google Chrome extension "HTML Tag Unclosed Checker"
A bookmarklet is also available
🔥 We’re currently testing a new version that checks tags with even greater accuracy. Please try it below.
Switch to the new version (you can switch back anytime)