I Hate JSON

JSON minifier — strip every spare byte

100% client-side

Input

empty
Or press Ctrl+Enter · max 50MB

Formatted

Your formatted JSON will appear here.

Two-space indent, syntax highlighted, ready to copy.

Make JSON as small as JSON gets

Paste JSON and press Minify. Every optional space, newline and indent is removed, and the result panel reports the before and after size with the percentage saved — a typical pretty-printed API response shrinks by 25–40%.

Everything runs in your browser. Your JSON is parsed by a Web Worker on your own machine and never sent anywhere — there is no upload, no account, and no server-side processing. You can check: open the network tab and format a file, and you will see no requests.

Lossless by construction

Minifying parses your document and re-serialises it, so the output is guaranteed to be valid JSON that parses back to exactly the same value. Only insignificant whitespace is removed: keys, values, ordering, numeric precision and Unicode escapes are all preserved. If the input will not parse, you get the line, column and the offending token highlighted rather than a corrupted file.

When minifying is worth it

Minified JSON is smaller over the wire and in storage, which matters for API payloads, config baked into bundles, and documents held in a database column. It is worth noting that gzip or brotli already removes most of the cost of whitespace in transit, so the biggest wins are where compression is not applied — local storage, embedded strings, and size-capped fields.

Questions

Does minifying change my data?

No. The document is parsed and re-serialised, so the result parses back to an identical value. Only whitespace between tokens is dropped.

Can I get the formatted version back?

Yes — minifying is fully reversible. Paste the minified output into the formatter and you get an indented document again.

Why does my file get slightly larger sometimes?

Rarely, re-serialising normalises a value — 1e2 becomes 100, for instance. The size line tells you honestly when this happens.

Is there a size limit?

The same 50MB cap as the other tools, with the work done in a Web Worker so the page stays responsive.