JSON minifier.
Minifies in your browser, nothing is uploaded. Related: JSON escape / unescape → · All free tools →
Minify JSON faster without the browser
The jsonbolt desktop app treats minified output as a first-class copy format. It parses files at 3 GB/s, so the same two clicks work on a multi-gigabyte document.
Copy JSON anywhere
A terminal, an API client, a log file, a browser tab, if it's on your clipboard, it's ready.
Press Win + J⌃ ⌥ J
jsonbolt launches and opens your clipboard in one step. (Opt-in: Settings → Launch.)
Copy it minified
Edit → Copy Selection Value As → Minified JSON puts it straight back on the clipboard. Select any subtree first to minify just that branch.
YAML, CSV, and XML export are built in.
What JSON minification does, and doesn't
A JSON parser ignores whitespace between tokens, so newlines, indentation, and the spaces after : and , are pure transport weight. Minification strips exactly those bytes: strings keep their contents character for character and keys keep their order. The one caveat is numbers, which are re-serialized, see below.
It is not compression. Gzip and brotli compress whatever bytes remain, and they stack with minification. A typical pretty-printed API payload shrinks 20–60% from minifying alone, then compresses further on the wire. Where minified JSON earns its keep: log lines that must stay on one line, payloads pasted into curl commands, and anywhere a byte budget is real.
How this minifier handles the details
- It validates first. Invalid JSON, trailing commas, single quotes, unquoted keys, shows the parser error with the exact position instead of producing broken output.
- Strings and keys are untouched, byte for byte, including unicode and escape sequences. Key order is preserved.
- Numbers are re-serialized in canonical form,
1.50becomes1.5,1e3becomes1000. Values beyond double precision are rounded, a JavaScript-engine limit: a 64-bit ID like9223372036854775807comes out as9223372036854776000. Keep IDs like that as strings. - The stats bar shows the real saving, bytes in, bytes out, and the conversion time.
- Everything runs locally. Your data never leaves the tab.
FAQ
How do I minify JSON?
Paste your JSON into the input pane at the top of this page. The minified version appears instantly with the size saving shown, copy it or download it as a .json file. Everything runs locally in your browser.
Does minifying change my data?
Mostly no. Whitespace is removed, and every key, string, boolean, and null is preserved byte for byte with key order intact. The one exception is numbers: they are re-serialized (1.50 becomes 1.5), and integers beyond 2^53 are rounded to double precision, so keep 64-bit IDs as strings.
How much smaller does minified JSON get?
Pretty-printed JSON typically shrinks 20–60%, depending on how deeply nested it is, deeper nesting means more indentation to strip. The stats bar above shows the exact saving for your document.
Is JSON minification the same as compression?
No. Minification removes characters a parser ignores; gzip or brotli compress the remaining bytes. They stack: servers usually gzip minified JSON, and the two together beat either alone.
Is my JSON uploaded to a server?
No. The minifier is a small script that runs entirely in your browser. Your data never leaves your machine, so it's safe for payloads containing API keys, tokens, or internal data.
How do I minify a very large JSON file?
Browser tools hold the whole document in tab memory, which gets painful past a few hundred megabytes. The jsonbolt desktop app parses at 3 GB/s, open the file or press Win + J⌃ ⌥ J for clipboard JSON, then Edit → Copy Selection Value As → Minified JSON.