How to use
- Paste JavaScript into the input — a site’s
.min.js, code squashed onto one line, or your own script. - Beautify breaks blocks onto their own lines and indents them. Choose the indent width, brace placement (same line or next line) and whether to keep blank lines.
- Minify strips comments, indentation and unnecessary spaces. Comments that start with
/*!or contain@licenseare kept by default. - Copy the result or download it as a
.jsfile, and check how much smaller it got.
How far does minify go?
Minify here puts never changing what the code does first. It shrinks less than a build tool, but any code you paste keeps working the same way.
| Does | Doesn’t |
|---|---|
| Remove comments (license comments optional) | Shorten variable and function names (mangling) |
| Remove indentation and blank lines | Drop unused code |
Remove spaces around { } ( ) ; , and operators like = |
Rewrite expressions (true → !0) |
| Join lines only where automatic semicolon insertion stays the same | Touch strings, regexes or template literals |
JavaScript has automatic semicolon insertion (ASI): a line break can end a statement. Gluing let a = 1 to a following let b = 2 is a syntax error, and removing the line break after return changes what’s returned. So in semicolon-free code those line breaks stay, and lines are joined only where it’s safe — after {, , or ;, or before a line starting with . such as .then(). Spaces that would turn a + +b or x - -1 into ++ or -- are kept too.
Example
function add (a, b) {
// add two numbers
return a + b
}This 59-byte snippet becomes function add(a,b){return a+b} (29 bytes), about 51% smaller. Comments and indentation go; the only space left is where two words would otherwise merge, between return and a. Line breaks after { and before } can’t change how statements are split, so they’re removed.
Things to watch out for
- For production, build tools like terser or esbuild shrink far more by mangling names and removing dead code. This tool is handy for quickly shrinking a single file or reading minified code.
- A regex right after
), as inif (x) /re/.test(s), can be mistaken for division, and spaces inside that regex may then be removed. Check the output for code like that. - Beautify can’t undo obfuscation (names already shortened to
a,b); it restores line breaks and indentation only.
FAQ
Is the code I paste executed?
No. It’s analyzed as text and never run, and it isn’t uploaded.
Can I format JSON or CSS too?
Use the JSON Formatter, the CSS Beautifier & Minifier or the HTML Beautifier & Minifier.