JSON Formatter
Beautify, validate and minify JSON data
🔒 100% free · no signup · files never leave your device
APIs rarely hand you pretty JSON. Responses get logged as a single minified line, config files arrive with inconsistent indentation, and one missing comma somewhere in 4,000 characters produces the famously unhelpful "Unexpected token" error. Reading or debugging JSON in that state is slow and error-prone — which is exactly why a JSON formatter and validator is one of the most-used tools in any developer's workflow.
This free online JSON formatter beautifies, minifies and validates JSON instantly in your browser. Invalid input doesn't just fail silently: you get the exact line and column of the first syntax error so the fix takes seconds instead of a manual hunt. Format mode applies clean 2-space indentation for reading and diffs; minify mode strips all whitespace for production payloads where every byte counts. Nothing is transmitted anywhere — safe for API responses that contain tokens, user data or anything else you'd rather keep on your own machine.
Why use JSON Formatter
Debugging an API response
Paste a minified response from a log or network panel, format it, and the structure of nested objects becomes immediately readable.
Hunting down a syntax error
The validator pinpoints the exact line and column of a trailing comma, unquoted key or missing brace in large config files.
Minifying JSON for production
Removing whitespace from a large JSON payload or config shrinks transfer size, useful for embedded devices and static hosting.
Preparing JSON for a diff or code review
Consistently formatted JSON produces clean line-by-line diffs instead of a wall of red in pull requests.
Pro tips
- JSON is stricter than JavaScript: no trailing commas, no comments, keys must use double quotes — the validator will catch all three.
- Fix errors from the top down. The first syntax error often produces confusing follow-on errors, so correct line 12 before worrying about line 900.
- Minify before storing JSON in size-limited places like JWT payloads, URL query strings or localStorage quotas.
- If your 'JSON' contains undefined or functions, it's a JS object literal, not JSON — serialize it with JSON.stringify first.
How to use JSON Formatter
- 1Paste your JSON
- 2Click Format or Minify
- 3See validation errors with exact position
- 4Copy the result
Frequently Asked Questions
Is my JSON sent to a server?▾
No — parsing and formatting happen 100% in your browser.
Can it fix invalid JSON?▾
It pinpoints the exact error location so you can fix it quickly, and shows a helpful message.