JSON Formatter, Validator and Minifier
Validate JSON, format indentation or minify output while preserving large integers and precise numbers.
Processed locally in your browser. Nothing is uploaded.
How to use
- Paste or import JSON.
- Choose indentation or minification.
- Copy or download the result.
Example and rules
Example: 9123372036854000123 retains its original value after formatting.
- Up to 2 MiB, UTF-8; BOM is accepted.
- Duplicate keys, comments and invalid JSON are rejected.
- Property order and precise numeric values are preserved.
Frequently asked questions
Are comments supported?
No. Input must be standard JSON.
Why reject duplicate keys?
To prevent silently overwriting data.
Are large integers rounded?
No. Numeric text is preserved.