What is the difference between beautifying and formatting JSON?
Nothing — they are two names for the same operation, and this tool and our JSON Formatter share the same engine. "Beautify" tends to be used when expanding minified JSON to read it; "format" when tidying JSON you are editing. The only difference here is the default indentation: 4 spaces for reading, 2 for editing.
Can I beautify a very large JSON file?
Yes, though there are practical limits. Because everything runs in your browser, the constraint is your device memory rather than an upload cap. Files up to a few megabytes are comfortable; beyond roughly 50 MB the browser will struggle and a command-line tool such as jq is a better fit.
Does beautifying change my data?
Only the whitespace. The tool parses your JSON into memory and re-serialises it, so values, types and array order are preserved exactly. One thing to note: duplicate keys are not preserved, because a JSON object cannot hold two identical keys — the last one wins, as it does in every JSON parser.