JSON formatter and validator
Paste JSON to pretty-print it with your preferred indentation, or minify it for production. Syntax errors are reported with the exact line and column. Works fully offline in your browser.
Everything runs in your browser — nothing is sent anywhere
How to use
- Paste your JSON into the box.
- Click Format to pretty-print or Minify to strip whitespace.
- Copy the result or download it as a .json file.
FAQ
Is my JSON uploaded?
No. Parsing and formatting run in your browser, so API keys or private data in the JSON never leave your machine.
Why does it say my JSON is invalid?
Common causes: trailing commas, single quotes instead of double, comments, or unquoted keys. The error message points to the line and column.
Does it preserve key order?
Yes. Keys stay in the order they appear in the input.
How large a file can I format?
Several megabytes work fine. Very large files may take a moment since the whole document is parsed in memory.