Shrink HTML and JavaScript by removing whitespace and comments, and see how much smaller it gets before and after gzip.
Choose what to keep: licence comments, original names.
It’s minified as you type, with syntax errors pointed out.
And see the size before and after gzip.
No — it runs the same, just downloads faster.
For real projects, let your build tool do it. This is for quick one-offs and checking sizes.
It uses the same engine as most build tools (Terser for JS). If your code has a syntax error, it stops and shows where.