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HTML Formatter & Validator

Pretty-print HTML (including embedded CSS and JavaScript), minify, catch mistakes like unpaired tags and duplicate ids, with a preview.

Formatting and checking HTML

The formatter uses Prettier, so CSS inside <style> and JavaScript inside <script> are tidied too. The checker uses HTMLHint to find unpaired tags, ids used twice, duplicate attributes, and images without alt text. Click a problem to jump straight to its line and column. The preview runs in a sandbox without JavaScript, and everything happens in your browser.

tags: #developer #html #format #validate

How to install the app

This browser has not offered an automatic install button yet. Install it from the browser menu:

Android (Chrome)
Tap the ⋮ menu at the top right, then choose "Install app" or "Add to Home screen".
iPhone / iPad (Safari)
Tap the Share button (the square with an up arrow), then choose "Add to Home Screen". On iOS this only works in Safari.
Computer (Chrome / Edge)
Click the install icon (a monitor with a down arrow) at the right end of the address bar, or menu ⋮ → "Install Daily Apps".