JSON Formatter & Validator
Beautify, minify and validate JSON instantly, with clear errors and line numbers. Everything happens in your browser: your data is never uploaded. Free, no sign-up.
🔒 100% private, processed locally in your browser. Nothing is uploaded.
How to format JSON
- Paste your JSON into the top box.
- Click Format to indent it, Minify to compress it, or Validate to just check it.
- Fix errors fast, invalid JSON shows the exact line and column that broke.
- Copy or download the result. Nothing leaves your device.
Common JSON errors this catches
- Trailing commas, valid in JavaScript, invalid in JSON.
- Single quotes, JSON requires double quotes around keys and strings.
- Unquoted keys, every key must be a quoted string.
- Missing or extra brackets/braces, the position pointer takes you straight there.
Frequently asked questions
Is my JSON uploaded to a server?
No. Formatting and validation run entirely in your browser. Your data is never sent over the internet or stored anywhere, which makes it safe for API responses, config files and anything containing keys or personal data. It also works offline.
What is the difference between format and minify?
Format (beautify) adds indentation and line breaks so JSON is easy to read. Minify strips all unnecessary whitespace to make the smallest possible payload, which is what you want for production APIs and config. Both produce valid, equivalent JSON.
How does validation help me find errors?
If the JSON is invalid, the tool shows the parser’s error message and points to the position, line and column, where it failed, so you can jump straight to the trailing comma, missing quote or stray bracket instead of hunting.
What does "sort keys" do?
It recursively reorders every object’s keys alphabetically. That makes two JSON files easy to compare in a diff, and gives you a consistent, canonical order, useful for config files and snapshots.
Does it handle large JSON files?
Yes, within your device’s memory, everything runs locally with no upload, so there is no size cap imposed by a server. Very large files (tens of MB) may take a moment to render.