Overview
Minify JavaScript to shrink and speed up your code
Minifying JavaScript removes everything a browser does not need to run the code: comments, line breaks, and indentation. A good minifier goes further and renames local variables to short names and folds away dead code, so the file gets dramatically smaller without changing what it does. Smaller scripts download faster and parse quicker, which directly improves page load speed and Core Web Vitals.
ToolHub JavaScript Minifier uses Terser, the same engine behind many modern build tools, and shows exactly how many bytes you save. Everything runs in your browser.
Step-by-step
How to minify JavaScript
- 1
Paste your code
Drop your JavaScript into the input panel. The example shows the kind of source you can paste. - 2
Watch it minify
The minified output appears instantly on the right, along with the original size, the new size, and the percent saved. - 3
Copy the result
Click copy to grab the minified code, ready to drop into a script tag or a bundle.
Smaller, faster
What minifying does to your code
- Strips comments and JSDoc blocks
- Removes line breaks and indentation
- Renames local variables and function arguments to short names (mangling)
- Drops unreachable and dead code
- Folds constant expressions and simplifies where it is safe to do so
The code behaves identically, but the file is often 30 to 60 percent smaller. Combined with gzip or Brotli compression on your server, the savings stack up.
Use cases
When to minify
Quick snippets
Minify a small script or inline snippet before pasting it into a page or template.
Embeds and widgets
Ship the smallest possible code for third-party embeds and tracking snippets.
Learning and inspection
See how a minifier transforms your source and how much each pattern costs in bytes.
Legacy projects
Minify standalone files in projects that do not yet have a build pipeline.
Email and size-limited contexts
Squeeze a script under a byte budget for places where every kilobyte matters.
Production builds
For whole projects, let your bundler minify automatically and keep an unminified source.
Tips and best practices
- Always keep an unminified source for editing and version control.
- Minify as the last step, after transpiling and bundling.
- For whole projects, let your build tool (Vite, esbuild, webpack) minify automatically.
- Minified code is hard to debug. Use source maps in real builds to map errors back to your source.
- Minification is not obfuscation. It is reversible enough that it does not hide your logic.
Common questions
How much smaller does minified JavaScript get?
Typically 30 to 60 percent before compression, depending on how many comments, long variable names, and whitespace the source has. The tool shows the exact percentage for your code.
Will minifying change how my code behaves?
No. Terser only renames locals and removes characters that do not affect execution. The minified output runs the same as your source.
What is the difference between minifying and obfuscating?
Minifying makes code smaller and is a normal production step. Obfuscating deliberately makes code hard to read to deter copying. Minified code is still understandable with effort, so do not rely on it for secrecy.
Why did I get a syntax error?
Terser parses your code before minifying, so it reports the same syntax errors a browser would. Check the line it mentions for a missing bracket, comma, or quote, then minify again.
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