JSON Formatter & Validator
Beautify, minify and validate JSON — with clear error messages when it's invalid.
100% private — everything runs in your browser and nothing is sent to a server.
Need this built into your own product?
We build web apps, APIs and integrations for startups and businesses — the same team that ships these free developer tools.
The JSON Formatter & Validator beautifies messy JSON into clean, indented form, minifies it back to a single line, and validates it with a clear message pointing at any error. It runs entirely in your browser, so the data you paste is never uploaded.
Why use this tool
Beautify and minify
Switch between neatly indented JSON and a compact single line.
Clear validation
Invalid JSON gets a readable error instead of a cryptic failure.
Private
Formatting happens in your browser — your data stays on your device.
How to use it
Paste your JSON
Drop in the JSON you want to format or check.
Beautify or minify
Choose indented output or a compact single line.
Copy the result
Grab the formatted JSON with one click.
Frequently asked questions
What does formatting JSON do?+
Beautifying adds consistent indentation and line breaks so JSON is easy to read; minifying removes all unnecessary whitespace to make it as small as possible. Neither changes the data itself.
Why is my JSON invalid?+
Common causes are trailing commas, single quotes instead of double quotes, or missing brackets. The validator points to where parsing failed so you can fix it.
Is my data sent anywhere?+
No. The JSON is parsed and formatted entirely in your browser, so nothing is uploaded — safe for sensitive payloads.
Is it free?+
Yes. Completely free, with no sign-up.