JSON Formatter

Format, validate, beautify, and minify JSON.

json-formatter.local
Output
Formatted JSON will appear here.

Overview

Formats messy or minified JSON into clean, indented, readable text, and flags errors if the JSON is invalid. Useful for inspecting API responses, config files, and anything where you need to actually read the structure. It runs in your browser, so your data is never uploaded.

How it works

The tool parses your input to confirm it is valid JSON, then re-serializes it with consistent indentation so the nesting is easy to follow. It can also minify JSON, stripping whitespace to produce the most compact form. If parsing fails, it points to the problem rather than producing output, which makes it a quick way to catch a stray comma or an unclosed bracket. Because everything happens locally, you can safely paste data that you would not want to send to a third-party server.

How to use it

  1. Paste your JSON into the input box.
  2. The tool validates it and formats it with proper indentation.
  3. Read or copy the cleaned-up output.
  4. If it is invalid, fix the error it flags and try again.

Examples

Reading an API response

Paste a one-line minified response and get an indented version where you can trace the keys and arrays.

Catching a syntax error

Drop in JSON that will not parse and let the tool point you to the spot that breaks it.

FAQ

Does it validate as well as format?
Yes. Invalid JSON will not format; the tool flags the error so you can fix it.
Is my data sent anywhere?
No. Parsing and formatting run in your browser, so your JSON stays on your device.
What counts as invalid JSON?
Common causes are trailing commas, single quotes instead of double quotes, unquoted keys, and unclosed brackets or braces.
Can it handle large files?
It works on sizable inputs, though very large files use more memory since everything is processed in the browser.
Can it minify too?
Yes. Alongside formatting, it can compress JSON into a single line with the whitespace removed, which is useful for shrinking payloads.

Related tools

Embed this tool

Paste this snippet to put the tool on your own site. It runs entirely in the visitor's browser, the same as it does here.

<iframe src="https://tooldok.com/embed/json-formatter/" title="JSON Formatter by Tooldok" width="100%" height="560" style="border:1px solid #16130d;border-radius:16px;max-width:720px" loading="lazy"></iframe> <p style="font:13px sans-serif"><a href="https://tooldok.com/tools/json-formatter/" target="_blank" rel="noopener">JSON Formatter</a> by <a href="https://tooldok.com/" target="_blank" rel="noopener">Tooldok</a></p>