JSON Formatter

About the JSON Formatter

The JSON Formatter beautifies, minifies, and validates JSON, with a collapsible tree view, diff mode, and JSONPath queries — a fast, private way for developers to read, debug, and clean up JSON data.

When you reach for a formatter

• An API returned 40KB on one line. The classic case. Beautify for indentation, then use the tree view to collapse the branches you don't care about and find the three fields you do.
• Something is malformed and the error is useless. "Unexpected token" with no position is one of the least helpful messages in programming. Validation here points at the actual character, which usually turns a twenty-minute hunt into ten seconds — it's nearly always a trailing comma, a single quote, or an unescaped quote inside a string.
• Staging and production disagree. Diff mode answers "what's actually different?" far faster than reading both responses side by side.
• You need one value out of a deeply nested structure. A JSONPath query pulls it without scrolling, which is the quickest way to confirm the data is really there before you go debugging your rendering code.
• You're embedding JSON in a page or config. Minify at the end; it's a real byte saving on something shipped to every visitor.

Why doing this locally matters

API responses routinely contain bearer tokens, API keys, session identifiers, email addresses and customer records. Pasting them into an online formatter that posts to a server is a habit that has caused real security incidents at real companies, and it's usually done without a thought because the tool looked like a text box.

This one parses in your browser. Nothing you paste is transmitted, because there's no endpoint to transmit it to — the page is a static file. If you'd rather verify than take that on faith, open your browser's network panel and paste something in; you'll see nothing leave.

A practical note on what JSON permits: comments are not valid JSON, trailing commas are not valid JSON, and keys must be double-quoted. A lot of "broken" JSON is actually JavaScript object literal syntax that was never valid to begin with — which is worth knowing, because the fix is different.

Works well with

If you're building something and hitting an unfamiliar API, the shipping a small website guide covers where this fits alongside palette, placeholder content and metadata. For quick byte and character counts on payloads, the Word Counter is next door.

Frequently Asked Questions