JSON Formatter & Validator
Beautify, minify and validate JSON in your browser — separate input/output panes, pinpoint syntax errors by line and column, sort keys, and download.
Format and check JSON in one place
Paste JSON and click Beautify to pretty-print it with clean indentation, Minify to strip whitespace for the smallest size, or Validate to confirm it parses and see the exact error if it doesn't. Everything runs in your browser, so your data never leaves your device.
Frequently asked questions
Is my JSON sent to a server?
No. Formatting and validation happen entirely in your browser using the built-in JSON parser.
Why does it say my JSON is invalid?
The validator shows the parser error, which usually points to a trailing comma, a missing quote, or single quotes used instead of double quotes.
Why did large ID numbers change after formatting?
JavaScript stores every JSON number as a 64-bit float, so integers beyond 9,007,199,254,740,991 (Discord/Twitter Snowflake or database bigint IDs) get rounded. The tool warns when your JSON contains one — keep those IDs as quoted strings to preserve them exactly.
How do I find exactly where my JSON is broken?
When parsing fails, the tool reads the browser JSON error and reports the offending character as "line X, column Y" — jump to that spot in the Source pane instead of hunting through a giant blob.
Can I change the indentation or sort the keys?
Yes — pick 2 spaces, 4 spaces or tabs, and tick "Sort keys" to alphabetize every object before beautifying.