Yes. All minification happens entirely in your browser. Your code is never sent to any server.

Will minification break my code?

Properly written code should work identically after minification. If issues occur, check for reliance on variable names or comments that get removed.

How much can minification reduce file size?

Typical savings range from 20-60% depending on the original code. Well-commented code with long variable names sees the largest reductions.

Code Minifier - Minify JavaScript, CSS, and HTML Online Free

How to Use the Code Minifier

Select the code type (JavaScript, CSS, or HTML), paste your code into the input field, and see the minified output instantly. The tool shows the original size, minified size, and percentage savings.

Features

JavaScript Minification - Variable mangling, dead code elimination, ES6+ support
CSS Minification - Shorthand optimization, color compression, duplicate removal
HTML Minification - Whitespace removal, comment stripping, inline CSS/JS minification
Size Comparison - See original vs minified size and savings percentage
Copy Output - One-click copy of minified code

Works great with the JSON Formatter for formatting minified JSON and Diff Checker to compare before and after.

What is Code Minification?

Minification is the process of removing all unnecessary characters from source code without changing its functionality. This includes removing whitespace, newlines, comments, and shortening variable names.

Benefits of Minification

Faster page loads - Smaller files download faster
Lower bandwidth costs - Less data transferred
Better caching - Smaller cache footprint
Improved SEO - Page speed is a ranking factor

JavaScript Minification

JavaScript minification includes:

Whitespace removal - Spaces, tabs, and newlines
Comment removal - Single and multi-line comments
Variable mangling - Shortening variable names (a, b, c instead of descriptive names)
Dead code elimination - Removing unreachable code
Constant folding - Pre-computing constant expressions

CSS Minification

CSS minification includes:

Shorthand properties - Combining margin-top/right/bottom/left into margin
Color optimization - #ffffff becomes #fff
Zero units - 0px becomes 0
Duplicate removal - Removing redundant declarations
Selector optimization - Merging identical selectors

HTML Minification

HTML minification includes:

Whitespace collapse - Multiple spaces become one
Comment removal - HTML comments are stripped
Attribute optimization - Removing optional quotes and values
Inline minification - Minifying embedded CSS and JavaScript

Frequently Asked Questions

Is my code secure?

Yes! All minification happens entirely in your browser using JavaScript. Your code is never uploaded to any server.

Should I use minified code in development?

No. Use readable, well-commented code during development. Minify only for production deployment. Keep your source files separate from minified output.

How do I debug minified code?

Use source maps. Most build tools generate source maps that let you debug minified code using the original source files.

Does minification affect performance at runtime?

No. Minified code runs identically to the original. The benefit is faster download times, not faster execution.

Code Minifier