JavaScript minifier
Terser in your browser: smaller JS, and clear errors when something is off.
How it works
- 01Paste your JavaScript or drop a .js file into the box.
- 02Pick what Terser may do: compress, shorten names, keep /*! comments, and treat the code as an ES module if it uses import or export.
- 03Copy the minified code or download it as a .min.js file.
Questions
›What does "Shorten names" do?
It renames local variables and function parameters to short names like a and b. Global names are left alone so other scripts can still find them. With ES module turned on, top-level names are shortened too, since nothing outside the module can see them.
›What does the output syntax setting change?
It tells Terser which JavaScript version it may use when rewriting your code, such as ES2015 shorthand properties. It doesn't convert modern syntax to older syntax: code that already uses newer features keeps them. Pick ES5 if the result must run in very old browsers.
›Does it support TypeScript or JSX?
No. Terser minifies plain JavaScript, so compile TypeScript or JSX to JavaScript first and minify the result here.
›Why do I get a syntax error?
Terser has to understand your code before it can shrink it, so a typo stops it. The error shows the line and column, and Show in input jumps straight there.
›Is my data uploaded anywhere?
No. This tool runs entirely in your browser, and Rounder never sends what you type or drop in to a server, ours or anyone else's. Once the page has loaded, along with any AI model the tool uses, it even works offline.