Bookmarklet

JSON Formatter Bookmarklet
for any browser

One click to format and syntax-highlight raw JSON on any page. No extension, no install. Drag it to your bookmarks bar and you're done.

Drag this to your bookmarks bar

Click and drag the button below into your browser's bookmarks bar.
Then visit any page with raw JSON and click it.

Format JSON

Tip: If you don't see your bookmarks bar, press Ctrl+Shift+B (Cmd+Shift+B on Mac) to show it.

How to use

Three simple steps

1

Drag to bookmarks

Drag the purple "Format JSON" button above into your browser's bookmarks bar.

2

Open a JSON page

Navigate to any URL that returns raw JSON (an API endpoint, a .json file, etc.).

3

Click the bookmark

Click "Format JSON" in your bookmarks bar. The page is instantly formatted with syntax highlighting.

Features

What the bookmarklet does

Syntax highlighting Keys, strings, numbers, booleans, and null each get distinct colors for easy scanning.
Pretty-printed output JSON is indented with 2 spaces, making deeply nested structures easy to read.
Dark theme Formatted output uses a dark background matching the jsonfmt.dev color scheme — easy on the eyes.
Error detection If the page content isn't valid JSON, you get a clear error message with the exact parse error.
Why a bookmarklet

Lightweight. Private. Universal.

🔒

100% Private

Runs entirely in your browser. Your JSON data never leaves your device — zero network requests.

⚡

No Install

No browser extension, no permissions, no updates. Just a bookmark — works in every browser.

🌐

Works Everywhere

Chrome, Firefox, Safari, Edge, Brave — any browser with a bookmarks bar supports it.

More Tools

Related JSON tools

JSON Formatter Online Full-featured JSON formatter with tree view, syntax highlighting, and collapsible nodes.
JSON Validator Validate JSON syntax and get clear, pinpointed error messages.
JSON Beautifier Beautify minified JSON with customizable indentation and formatting options.
JSON Minifier Compress JSON by removing whitespace — reduce payload size for APIs and storage.

Need more than a bookmarklet?

Try the full JSON Formatter with tree view, diff, 33 converters, and 60+ tools.

Open JSON Formatter