Strict, but tiny
JSON has only 6 value types (object, array, string, number, boolean, null)—no dates, no comments, no NaN. That’s why tools lean on strings for timestamps.
Minimal spec
JSON Formatter & Validator — Beautify, Minify, Lint
Formatter
Input: 0 B
Output: 0 B
Saving: —
Shortcuts: Ctrl/Cmd + Enter — Pretty (2). Ctrl/Cmd + Shift + M — Minify.
About this tool
This JSON Formatter & Validator helps you clean up and check JSON quickly, right in your browser. Whether you are working with API responses, configuration files, or data exports, it makes raw JSON readable and confirms that the syntax is valid before you use it elsewhere.
JSON is a lightweight format for storing data as objects and arrays. Small errors like missing quotes, extra commas, or mismatched brackets can make a file invalid and break an app or API request. This tool validates your input using the browser’s native JSON parser, then formats it with consistent indentation so you can spot issues and understand the structure at a glance.
To use it, paste your JSON into the editor, choose Pretty or Minify, and run the formatter. Pretty-printing makes nested data easier to read, while minifying removes whitespace for compact storage or network transfer. You can also enable options to sort object keys for clean diffs and attempt to fix common trailing commas before validation.
This is especially useful when you are debugging a web API, preparing data for a database import, cleaning up a configuration file, or sharing a payload with teammates. Developers often use a JSON pretty printer to review logs, and a JSON minifier to reduce file size when shipping data.
Shortcuts can speed up your workflow: Ctrl/Cmd + Enter pretty-prints with two spaces, and Ctrl/Cmd + Shift + M minifies instantly. Because everything happens locally in your browser, your data never leaves your device.
Whether you need a JSON validator, a JSON formatter, or a quick way to fix and clean JSON, this tool provides a reliable, easy-to-understand workspace for daily development and data tasks.
FAQ
Does any JSON I paste get uploaded?
No. Everything runs locally in your browser. Nothing is sent anywhere.
Why do I see “trailing comma” errors?
Standard JSON does not allow trailing commas. Enable the “Attempt to fix trailing commas” option to remove common cases before parsing.
What does “Sort object keys” do?
It alphabetically sorts keys in objects, which helps with diffing and stable output. It does not change arrays.
5 Fun Facts about JSON
53-bit ceiling
Parsed in JavaScript, integers above 9,007,199,254,740,991 lose precision (double math). JSON itself allows them—but JS can silently round them.
Big number gotcha
Order is a polite illusion
The spec says object key order is meaningless, yet modern engines preserve insertion order. Sort keys if you want deterministic diffs—not because JSON guarantees it.
Stability trick
Emoji need two escapes
Unicode escape sequences are 16-bit. A rocket 🚀 becomes \"\\uD83D\\uDE80\" in JSON—two code units, one emoji.
UTF-16 peek
Line-delimited superpower
JSON Lines/NDJSON keeps one JSON object per line, letting you stream logs, grep them, or append forever without re-serializing the whole file.
Streaming friendly