In this presentation, we explain how and why NLnet runs its systems on NixOS. NLnet has grown from a small organization handling tens of grants per year to one that handles hundreds of grants per year. The number of funding proposals is more than five times as high. Still, NLnet runs mostly on Free Software. In the last years we have moved most of our systems to NixOS and keep our system setups in a single git repository handled with nixos-rebuild. In this presentation, we explain how and why we do so.