[ewuhic]

Does it cache dependency crates to nix store? Does it result to speed-up in builds?

[domenkozar]

Yes, it does vendor all the crates to Nix store.

It results into speed up in a way that if your application doesn't change, you'll just get the binary package.

That's why the two interfaces are exposed: one for development feedback cycle and one for distribution.

[ethan_smith]

Yes, it caches compiled crates in the Nix store which significantly speeds up builds, especially for projects with large dependency trees.