uv: An extremely fast Python package and project manager, written in Rust

The biggest speed-up in uv comes from the way it uses caching and hard links. When you install a package into a virtual environment uv uses a hard link to a previously cached version rather than copying files.

Using Rust is responsible for a lot of speed gains too, but I believe it's the hard linking trick (which could be implemented in any language) that's the biggest win.

There's also the assumptions around wheels having consistent metadata (which isn't required in older versions of the specs), so as long as you don't need to support the long tail of packages, then those assumptions are fine (it's worth noting uv weren't the first to make these assumptions, poetry did this too, but pip does not).