zip-over-range

Could I look inside a giant ZIP without downloading the whole thing? Turns out, yes. ZIP files store their index at the end. A couple of HTTP Range requests, and you can read the table of contents of a multi-gigabyte archive using only kilobytes.

This runs entirely in the browser. No server, no uploads. Point it at a URL and browse what’s inside. Click a file to download just that one.

I wrote a detailed breakdown of the ZIP architecture and the technique behind this in a blog post. The kind of project where the research was half the fun.