When building extensions for databases, it can become burdensome to make sure you build and deploy matching versions. This often involves changing the version number in multiple places or custom scripting, in particular when deploying extensions to other environments. In this talk I will cover two cases of building database extensions for PostgreSQL and Redis, as well as how to use Nix to manage Python environments to run tests against temporary instances of the database. Finally I will briefly discuss building docker images for the database with the extension installed. --- Bio: John is a software engineer at InfoSum, where he works on the core components of their customer data platform. At InfoSum, he uses Nix to build several C projects as well as managing python dependencies, and has been using NixOS as his primary operating system for over a year. In his free time, John enjoys experimenting with Haskell, playing board games and going bouldering.