JSON Formatter

Paste messy or minified JSON and get a clean, syntax-highlighted version with clear error messages — free and instant. Your data is processed entirely in your browser and never uploaded.

How to use the JSON Formatter

  1. Paste your JSON. Drop in an API response, a config file, a log entry or any other JSON text. The tool validates it live as you type.
  2. Choose your options. Pick 2-space, 4-space or tab indentation, and optionally sort all object keys alphabetically for easier diffing.
  3. Format and export. Press Format JSON to beautify (or Minify to compress). Copy the highlighted result to your clipboard or download it as a .json file.

About this tool

This free online JSON formatter beautifies, validates and pretty-prints JSON in one step. It is ideal for making sense of minified API responses, debugging webhook payloads, cleaning up configuration files, and preparing readable examples for documentation. Keys, strings, numbers, booleans and null values are color-coded with syntax highlighting, and when your JSON is broken the validator points to the exact line and column of the first error, with a snippet showing where parsing failed. A one-click minifier is also included for when you need the smallest possible payload.

Everything runs locally in your browser using the native JavaScript JSON parser — the same one used by Chrome, Firefox and Node.js — so your data is never uploaded, stored or logged. That makes it safe to format API keys, tokens, customer records and other confidential JSON, and it works even for large multi-megabyte files.

Frequently asked questions

Why does the validator say my JSON is invalid?

The most common causes are trailing commas after the last item, single quotes instead of double quotes, unquoted property names, comments (JSON does not allow // or /* */), and special values like NaN, Infinity or undefined. The error message shows the line and column where parsing first failed, which is usually at or just after the actual mistake.

Does formatting change my data?

Formatting only changes whitespace, but be aware of how JavaScript re-serializes values: number notation is normalized (1e2 becomes 100, 1.50 becomes 1.5), integers larger than 2^53 lose precision, and if an object contains duplicate keys only the last value is kept. For typical JSON none of this matters, but keep it in mind for financial IDs or scientific data.

Is my JSON uploaded to a server?

No. Parsing, validation, highlighting and minification all happen inside your browser with client-side JavaScript. Nothing you paste ever leaves your device, so the tool is safe for private or sensitive data and even works offline once the page has loaded.

What is the difference between formatting and minifying?

Formatting (beautifying) adds line breaks and indentation so humans can read the structure. Minifying removes every unnecessary space and newline so the file is as small as possible — ideal for sending over the network or embedding in code. Both produce exactly equivalent JSON.