About json-format.online
A free, privacy-respecting JSON tool that runs entirely in your browser.
What it does
json-format.online lets you format, validate, and inspect JSON without sending your data anywhere. Everything runs locally using your browser's built-in JavaScript engine.
- Format — pretty-print JSON with 2 spaces, 4 spaces, or tabs.
- Validate — instantly know whether your input is valid JSON and, if not, exactly where the error is.
- Minify — strip all whitespace for compact output.
- Copy — put the formatted result on your clipboard in one click.
- Inspect — see the root type (object, array, string, …), item count, and byte size at a glance.
- Syntax highlighting — keys, strings, numbers, and literals are color-coded for readability.
How it works
When you click Format, the page runs JSON.parse followed by JSON.stringify
directly in your browser tab. No network request is made. Your JSON never leaves your device.
No installation needed
The tool is a single HTML page with a stylesheet and a script. You can open it directly from disk, serve it from any static host, or save it for offline use. There are no dependencies, no build step, and no server.
Contact
Found a bug or have a suggestion? Open an issue on the project repository.