JSON formatter
Format, minify, and validate JSON.
Mode
Indent
Everything runs in your browser. Nothing is uploaded.
How it works
Paste JSON
Paste a JSON document — an API response, a config file, a blob you found in a log.
Pick a mode
Pick an indent (2, 4, or tab) for pretty-print, or switch to minify for a one-liner. Validate-only also reports where parsing fails.
Copy or download
Copy the result, or download it as a .json file. Nothing is sent to a server.
Questions
What does this tool do?
The JSON Formatter pretty-prints, minifies, and validates JSON entirely in your browser. Paste an API response, a config file, or a blob you pulled from a log, then choose an indent style — two spaces, four spaces, or tabs — to format it for readability, or switch to minify to collapse it into a single compact line. When the JSON is invalid, the validator reports the exact line and column where parsing fails, so you can jump straight to the missing bracket or stray comma instead of hunting for it.
Does my JSON leave my device?
No. JSON is parsed and re-serialised inside the browser with the standard `JSON.parse` / `JSON.stringify`. Nothing is uploaded.
Where does the error come from?
When parsing fails, the error message reports a character position. The formatter translates that into the line and column inside your input so you can jump straight to the offending bracket.
Does it work offline?
Yes — the page works offline after the first load. The whole formatter is a few KB of JavaScript.