JSON Formatter & Validator
Format, minify, and validate JSON with syntax highlighting, error messages, and structure stats — all in your browser with zero data upload.
Input
Output
Formatted output will appear here.
Why use this JSON formatter?
Instant formatting
2-space or 4-space indent, or minified — choose your style.
Syntax highlighting
Keys, strings, numbers, booleans, and null — each a distinct color.
Validation with errors
Exact SyntaxError messages so you know where to look.
Depth & key stats
See how deeply nested your JSON is and total key count at a glance.
Download as .json
One-click download of the formatted output.
Zero data upload
Everything runs in your browser — nothing is sent to any server.
Frequently asked questions
Is my JSON data private?
Yes. All processing happens in your browser using JavaScript. No JSON data is ever sent to our servers.
What's the difference between Format and Minify?
Format adds indentation and line breaks for human readability. Minify removes all whitespace to reduce file size — useful for APIs and storage.
Can I format very large JSON files?
Yes, as long as your browser can handle the memory. Files up to a few hundred MB typically work fine on modern hardware.
Why does validation fail on valid-looking JSON?
Common culprits: trailing commas, single quotes instead of double quotes, unquoted keys, and comments (JSON doesn't support // or /* */). The error message pinpoints the exact location.