JSON Formatter
Runs on your device. Nothing is sent.Everything happens on your own device. Your JSON is never sent anywhere.
Drop a .json file here
Format, validate, and explore JSON entirely in your browser - nothing is uploaded anywhere.
JSON (JavaScript Object Notation) is the standard format for exchanging data between web APIs, config files, and app settings. A single misplaced comma or missing quote can break an entire response, which is why validating and formatting JSON before you use it matters. This tool parses your JSON locally in the browser, points out exactly where a syntax error is, and lets you reformat, minify, or browse it as a tree - no server ever sees your data.
Frequently asked questions
What is JSON used for?
JSON is the default data format for most web APIs, mobile app backends, and configuration files (like package.json in Node.js projects). It's readable by both humans and machines, which is why it replaced XML for most modern data exchange.
Why does my JSON show a syntax error?
The most common causes are a trailing comma after the last item, missing quotes around a key, single quotes instead of double quotes, or an unclosed bracket. The error message shows the exact line and column so you can jump straight to the problem.
What's the difference between formatting and minifying?
Formatting adds indentation and line breaks so the structure is easy to read. Minifying strips all of that whitespace to produce the smallest possible file - useful when you're sending JSON over a network and don't need it to be human-readable.
Is my JSON data uploaded anywhere?
No. Parsing, formatting, and validation all run locally in your browser using JavaScript - your JSON never leaves your device or touches a server, even when you upload a file instead of pasting text.
What does the Sort Keys button do?
It recursively sorts every object's keys alphabetically at every level of nesting, while leaving array order untouched. That makes it much easier to diff two JSON files or API responses that hold the same data but were serialized with keys in a different order.
How do I find a specific value inside a large JSON file?
Switch to Tree view and type into the search box - matching keys and values get highlighted and their branches automatically expand, even deep inside nested objects or arrays. Click a node's Copy Path button to copy its exact location, like $.users[0].email, so you can reference that field directly in your own code.
For developers: open this page with a `q` parameter in the URL - e.g. gizke.com/json?q={"hello":"world"} - and that value is pre-filled automatically. Most visitors won't need this; it's meant for linking directly to a ready-to-use example.