What is a JSON Formatter?
A JSON formatter (also called a JSON beautifier) takes compact or messy JSON — the kind you get from an API response, a log file, or a minified config — and rewrites it with consistent indentation and line breaks so it's easy for a human to read and debug.
How to use this JSON formatter
- Paste or type your JSON into the left-hand box.
- Choose your preferred indentation — 2 spaces, 4 spaces, tab, or minified.
- Click Format JSON. Valid JSON is instantly pretty-printed on the right; invalid JSON shows exactly where the error is.
- Click Copy Output to copy the result to your clipboard.
Why use this tool
- 100% client-side — your data never leaves your browser, so it's safe for private API responses or config files.
- Instant validation — if your JSON is malformed, you get a precise line/column error instead of a silent failure.
- No sign-up, no limits — free to use as often as you like.
Frequently asked questions
Is my JSON data uploaded anywhere?
No. This formatter runs entirely in your browser using JavaScript. Your JSON is never sent to a server, so it's safe to use with private or sensitive data.
What's the difference between formatting and minifying JSON?
Formatting (beautifying) adds indentation and line breaks to make JSON easy to read. Minifying removes all unnecessary whitespace to make the JSON as small as possible, which is useful for production APIs and file size.
Why does my JSON show an error when I try to format it?
The formatter uses your browser's built-in JSON parser, which follows the strict JSON specification. Common mistakes include trailing commas, single quotes instead of double quotes, unquoted keys, or missing brackets. The error message tells you the exact line and column where parsing failed.
Can I format very large JSON files?
Yes, since everything runs locally in your browser there's no upload size limit like you'd hit with a server-based tool. Very large files (tens of MB) may be slower depending on your device.