JSON Formatter & Validator

Paste JSON to beautify, minify and validate it — with clear error messages and a collapsible tree view. Runs entirely in your browser.

Read the guide: How to Format and Validate JSON
Valid JSON · 144 B in · 174 B formatted
Input
Output

How it works

  1. 1

    Paste JSON

    Drop in raw or messy JSON on the left. It is validated as you type.

  2. 2

    Format or minify

    Pick an indent and hit Format for a clean, readable document, or Minify to strip whitespace.

  3. 3

    Copy or explore

    Copy the result, download it, or switch the output to an interactive tree to inspect the structure.

Instant & 100% private — nothing is uploaded

Everything runs locally in your browser. Your code, text and files are processed on your own device and are never sent to a server — so there are no upload waits, no size limits from us, and nothing is ever stored or logged.

Frequently asked questions

Does the formatter validate my JSON?
Yes. Invalid JSON shows a precise error message with the reason it failed to parse, so you can fix it quickly. Valid JSON is confirmed with a size summary.
What is the difference between format and minify?
Format (beautify) adds consistent indentation and line breaks so JSON is easy to read. Minify removes every non-essential character to produce the smallest valid JSON for transport.
Can it handle large JSON files?
Yes. Because it runs locally, the practical limit is your device’s memory rather than an upload cap. Very large documents are best viewed minified or via the tree.
Is my data sent to a server?
No. Everything runs locally in your browser using JavaScript and WebAssembly. Your input never leaves your device, nothing is uploaded, and nothing is logged or stored.