JavaScript Minifier — Free Online Tool

The JavaScript Minifier removes comments and whitespace and shortens local variable names so a script downloads and parses faster while behaving exactly as before. On unminified source the size reduction is usually somewhere between 30 and 60 percent, and because JavaScript costs far more to parse and execute per byte than CSS or HTML does, that reduction converts fairly directly into a faster interactive page on mid-range phones.

It is worth being precise about what minification does and does not touch. Local variable names inside a function can be safely shortened because nothing outside can see them; anything reachable by name from elsewhere — global functions, exported symbols, object properties accessed as strings, code called from inline HTML attributes — must keep its name. Minifiers are conservative about this, which is why heavy use of eval, with, or dynamically constructed property names limits how much a minifier can safely do.

The practical caveat is debugging: a stack trace from minified code points at column 4,812 of one line and tells you nothing. Production builds normally ship a source map alongside so errors can be mapped back to the original source, and any real build pipeline handles minification for you. This tool is for the cases in between — a standalone script, an inline snippet, a widget you are handing to someone else.

Everything runs in your browser; your source is never uploaded.

Our JavaScript Minifier is completely free to use with no signup required. For this tool, processing runs in your browser — your files and data stay on your device and are not uploaded to our servers.

Whether you are a developer, designer, student, or business owner, this tool is designed to save you time and make your workflow more efficient. Bookmark this page to access it whenever you need it — it will always be free.