Tools / JSON Formatter
JSON Formatter & Validator
Paste JSON to format, minify or validate it. Errors are reported with the exact line and column, and everything runs in your browser.
Tip: paste a minified API response and press Format to make it readable.
What this tool does
JSON is whitespace-insensitive, which means a minified payload and a pretty-printed one contain exactly the same data. This tool converts between the two and tells you precisely where a syntax error is.
How to use it
- Paste JSON into the left box.
- Click Format for readable output, or Minify to compress it.
- Click Validate to check syntax without changing anything.
- Copy the result.
FAQ
Why is my JSON invalid?
The usual culprits: trailing commas, single quotes, unquoted keys, and // comments. Standard JSON allows none of them — JSON5 and JSONC do, but browsers do not.
Is my data uploaded?
No. Parsing happens locally with the browser's own JSON parser.
Which is smaller after minifying?
Minifying removes indentation and newlines, typically saving 10–30% depending on nesting. For real compression, gzip on the wire does far more.