JSON-pienennin

A JSON minifier validates your JSON and strips out every unnecessary character, the spaces, indentation and line breaks that make JSON readable, then reports how many bytes and what percentage you saved.

Minified JSON is identical in meaning to the formatted version; only the cosmetic whitespace is gone. That makes it the right form for production: API responses, config bundled into an app, or any payload where transfer size and parse time matter.

It runs in your browser using the native JSON engine, so the output is exactly what your own code would produce. Because it parses first, a successful minify also confirms your JSON is valid; invalid input returns a precise error instead.

One subtle effect is number normalization, which is part of the JSON standard rather than this tool: 1.50 becomes 1.5 and 1e3 may be rewritten, because those represent the same value. Keys, strings, booleans and structure are never changed.

Minification and gzip are complementary, not alternatives. Servers usually gzip responses, which compresses repeated text heavily; minifying first removes whitespace the compressor would otherwise have to handle, and the two together give the smallest transfer.

When you need to read or edit JSON instead of shrink it, the JSON Formatter does the reverse, pretty-printing it with clean indentation. Nothing you paste here is uploaded.