JSON Formatter & Validator
Paste raw or minified JSON to pretty-print it with your preferred indentation, or collapse it to a single line. Real-time validation highlights errors with the native browser message so you know exactly what went wrong. Everything runs in your browser — nothing is sent to a server.
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Frequently Asked Questions
What is JSON?
JSON (JavaScript Object Notation) is a lightweight text format for storing and transporting structured data. It uses key-value pairs and ordered arrays, and is the standard data format for web APIs and configuration files.
Why is my JSON invalid?
Common mistakes include: trailing commas after the last item in an object or array, single-quoted strings (JSON requires double quotes), unquoted property names, and using JavaScript values like undefined or NaN, which are not valid in JSON.
What does "Format / Make it Pretty" do?
It re-serializes your JSON with line breaks and your chosen indentation (2 spaces, 4 spaces, or tab) so the structure is easy to read at a glance. The JSON content itself is unchanged.
What does "Minify" do?
Minify removes all whitespace (spaces, tabs, newlines) that is not inside a string value, producing the most compact valid representation. Useful for reducing payload size when sending JSON over a network.
What does "Sort Keys" do?
It alphabetically sorts the keys of every object in your JSON, recursively. This makes it easier to compare two JSON documents or spot a missing field. Array order is always preserved.
Is my JSON data private?
Yes. All processing happens entirely in your browser using JavaScript. Your JSON is never uploaded to any server.