JSON Formatter & Validator
Format, validate, and pretty-print JSON instantly. Everything stays in your browser.
Input
Output
Formatted JSON appears here as you type.
Questions
How do I format JSON?
Paste it into the input box, or drop a .json file on it. The formatted version appears on the right as you type. Pick 2 spaces, 4 spaces or tabs for indentation, or Minify to strip all whitespace. Then copy or download the result.
How does validation work?
Your input is checked against the JSON standard on every change. If something is wrong, you get a plain-English message with the line and column, a preview of the offending line, and a button that jumps your cursor straight to it. Common mistakes like trailing commas, single quotes, unquoted keys and comments are called out by name.
Will formatting change my data?
No. Only whitespace changes, and key order if you turn on sorting. Strings and numbers are kept exactly as written, so very large numbers like IDs aren't rounded and duplicate keys aren't silently dropped.
Is my JSON uploaded?
No. Everything runs in your browser and nothing is sent anywhere, so it's safe for API responses, config files and other private data. Nothing is stored after you close the tab.