Blazing-Fast Minifier

mni

A world-class minifier for JavaScript, CSS, and JSON. Built on SWC (powers Next.js, Deno) and LightningCSS (100x faster than cssnano).

View on GitHubView on Crates.io
7x
Faster than Terser
100x
Faster than cssnano
30-45%
Compression
v0.1.0
Current Version

Production-Ready Features

Battle-Tested

Built on SWC and LightningCSS, used in production by millions.

Blazing Fast

7x faster than Terser, 100x faster than cssnano.

Safe by Default

Conservative optimizations that never produce invalid code.

Multi-Format

JavaScript (ES5-ESNext), CSS, and JSON in one tool.

Smart Detection

Auto-detects file format. Rich CLI with presets.

Source Maps

Optional source map generation for debugging.

Performance Benchmarks

FormatOriginalMinifiedReductionTime
JavaScript1,307 B757 B42.1%18ms
CSS1,657 B1,218 B26.5%6ms
JSON671 B519 B22.7%<1ms

Usage

Basic Usage

mni input.js -o output.min.js

Minify JavaScript

mni styles.css -o styles.min.css

Minify CSS

mni data.json -o data.min.json

Minify JSON

mni input.js --stats

Show statistics

Presets

mni input.js --preset dev

Fast, readable, source maps

mni input.js --preset prod

Balanced compression & speed

mni input.js --preset aggressive

Maximum compression

Optimization Techniques

JavaScript (SWC)

  • Identifier mangling
  • Dead code elimination
  • Constant folding
  • Scope hoisting
  • Arrow function optimization

CSS (LightningCSS)

  • Color minification
  • Length optimization
  • Property merging
  • Vendor prefix optimization
  • Calc() optimization

JSON (serde_json)

  • Whitespace removal
  • Key ordering
  • UTF-8 optimization

Installation

$ cargo install mni

One Tool for All Minification

JavaScript, CSS, and JSON. Blazing fast. Production ready.

Get Started on GitHub