JSON Formatter & Validator
Format, validate, minify, and explore JSON — instantly, in your browser.
100% in your browser — files never leave your device
Output appears here.
Frequently asked questions
Is my JSON uploaded anywhere?
No. Parsing, formatting, and validation all happen in your browser with the native JSON engine. Nothing is sent to a server.
How big a file can it handle?
It handles multi-megabyte documents comfortably. Very large files (tens of MB) may be slow to render in tree view — use formatted or minified view instead.
What does the validator check?
It runs the standard JSON parser and reports the exact error message and position when the document is not valid JSON.