JSON formatter
Validate, explore and repair without losing large integers.
Loading your local tool…
Input JSON
Paste JSON, drop a file, or try Example. Ctrl / ⌘ + Enter formats.
Large integers stay exact; inputs are not autosaved. Ctrl / ⌘ + F finds, Ctrl / ⌘ + Z undoes. Tab indents (Escape then Tab leaves the editor).
Comparing two JSON documents? Open JSON diff →How to use, privacy & sources
How to use & assumptions
01 / Paste text or import a file. Validation errors include line and column; duplicate fields are reported separately.
02 / Repairs require preview and explicit application. The tree includes field paths, and exports retain large integer digits.
Privacy and results
Files and inputs are processed in this browser, without sending them to our servers. Saving scenarios is explicit and stores them on this device; clear site data on shared devices.