Does minification change values?

No. Only insignificant whitespace is removed and the result is parsed back and compared with the input. The badge turns amber only when you enable the lossy strip-null or strip-empty options.

What is the gzip size for?

It is the number of bytes that would actually travel over an HTTP connection with content-encoding: gzip, measured in your browser. Use it when deciding whether minification matters for your payload.

When would I use Base64url?

When the JSON has to live inside a URL, cookie or HTTP header. Base64url uses - and _ instead of + and / and drops the padding, so it needs no further escaping.

JSON Minifier

Strip whitespace, newlines and indentation from JSON to produce the smallest valid representation, and see what it actually saves after gzip. Optionally drop null and empty values, sort keys, minify NDJSON line by line, and output as Base64, Base64url or URL-encoded text for query strings and headers. Every result is round-trip verified.

Runs locally in your browser

For large JSON, open fullscreen for a wider view

JSON input

0 chars · 1 line

Minified

Output will appear here…

Output

Input

Sort keys alphabeticallyStrip null valuesStrip empty strings, arrays, objects

gzip sizes are measured in your browser with CompressionStream; brotli appears only where the browser supports it. Base64url and URL-encoding are for embedding the payload in query strings or headers.

JSON Formatter

Beautify, minify, sort, query and repair JSON with a tree view and copy-as code export.

JSON Validator

Validate JSON syntax and JSON Schema, catch duplicate keys and precision loss, check NDJSON line by line.

JavaScript Minifier

Minify JavaScript with Terser or beautify JS/TS with Prettier — with real gzip sizes.

CSS Minifier

Minify CSS safely — strings, url() and calc() preserved — with gzip size and duplicate-selector merging.

How to use JSON Minifier

1Paste or upload JSON (or NDJSON and switch the input mode).
2Choose the output: plain minified, Base64, Base64url or URL-encoded.
3Optionally sort keys, strip null values or strip empty strings, arrays and objects.
4Compare the original, minified and gzip sizes in the stats, then copy or download.

About JSON Minifier

JSON Minifier is part of FizzKit — a collection of focused developer and ad-tech tools. Because everything runs locally, it works offline once loaded and never exposes your data to a remote server.

Frequently asked questions

Typical savings are 20–40% before compression. After gzip the difference is much smaller because compression already removes most whitespace, which is why the tool shows both numbers.

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