JSON formatter

Free · no sign-up

Format, validate and minify JSON — right in your browser, nothing is uploaded.

Indent:

Input

Output

Format, validate and minify JSON in seconds — right in your browser. Paste messy or minified JSON and this free formatter pretty-prints it with the indentation you choose, or compresses it back to a single line. If the JSON is invalid, it shows you exactly what's wrong. Nothing is uploaded — your data is parsed locally and never leaves the page.

✓Pretty-print with 2 spaces, 4 spaces or tabs
✓Minify JSON back to a compact single line
✓Instant validation with a clear error message
✓Copy the result in one click
✓Runs entirely in your browser — nothing uploaded

Who it's for

Developers debugging an API response
Cleaning up a config or export file
Minifying JSON to shrink a payload
Validating JSON before pasting it into code

How it works

1Paste your JSON into the input box.
2Choose your indentation, then press Format (or Minify).
3Fix any error the validator points out.
4Copy the formatted output.

Frequently asked questions

Is my JSON sent to a server?+

No. The JSON is parsed and formatted entirely in your browser using the built-in JSON engine. Nothing is uploaded, logged or stored — it's safe for sensitive data.

What does “minify” do?+

It removes all unnecessary whitespace and line breaks, producing the smallest valid JSON on a single line — handy for configs, API payloads and reducing size.

Why does it say my JSON is invalid?+

The formatter uses a strict parser, so it flags issues like trailing commas, single quotes, unquoted keys or missing brackets — and shows the error so you can fix it fast.

What's the difference between JSON and a JavaScript object?+

JSON is a strict text format: keys and strings must use double quotes, with no trailing commas and no comments. This tool validates against that standard.

Is there a size limit?+

It handles large documents comfortably since everything runs locally, though very large files depend on your device's memory. For everyday API responses and configs it's instant.