How it works
The input goes through the browser’s own JSON.parse, the strictest parser available, then JSON.stringify with your indentation. Sort keys orders object keys alphabetically at every depth, which makes two documents easy to diff.
When parsing fails, the tool converts the engine’s error message to a line and column so you can jump straight to it.
Common errors
| Message | Usual cause |
|---|---|
Unexpected token } |
trailing comma after the last item |
Unexpected token ' |
single quotes: JSON needs double quotes |
Unexpected token / |
comments: JSON has none (use JSON5 or JSONC tooling) |
| Bad control character | a raw tab or newline inside a string: escape it as \t or \n |
Limits
- Large numbers beyond 2^53 lose precision when re-serialized, as in any JavaScript tool.
- Files are read locally; nothing is uploaded. Big documents (tens of MB) work but take a moment.