We have been working on improving our Nix integration, aiming for every repl to be backed by Nix, and removing the additional loading time when opening a Nix-based repl. This improvement is made possible through caching environment variables exported by nix-shell, reducing startup times from tens of seconds to just a few seconds. The Nix integration uses a purely functional language for configuration and build steps, storing outputs in the Nix store, which is seeded with a vast majority of packages in the nixpkgs repository. By persisting environment variables to the repl's filesystem, we can skip the Nix evaluation step on startup, making the experience just as good as our existing Polygott solution.