Minifying JSON removes every byte the parser does not need: indentation, line breaks and the spaces around colons and commas. The data is untouched — keys, values, ordering and nesting stay exactly as they were — but a pretty-printed config or API fixture usually shrinks by 20-40%, and deeply indented files by more. That matters for API responses measured per request, for localStorage where browsers cap you around 5 MB, and for anything embedded in a build artefact. The minifier parses your input first, so invalid JSON is reported with the position of the problem instead of being blindly compressed into something still broken.
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