Nix is a fantastic tool for managing the dependencies of your development projects, but ironically the Nix language itself has very limited facilities for modular code reuse and composition. In this talk, I will present on my recent experiments with a system, inspired by node.js's "require" mechanism, to define packages of nix language code that can depend on other packages. Together with conventions encouraging detailed documentation, good error messages, and clean interfaces, I hope this project can form the seed for a robust ecosystem of libraries and tools that can help move us past the monolith of nixpkgs and enable us to more easily benefit from each others' work. --- Bio: Shea is a lead engineer at Target's data science and optimization group, whose production stack is built with Nix. He has been part of the NixOS community since 2010, has been working professionally with Nix since 2012, and is part of the Nix core team.