> For our backend, we deploy it as a nix package on NixOS, so we can atomically rollback the deployed code, as well as any dependencies like system libraries S

> For our backend, we deploy it as a nix package on NixOS, so we can atomically rollback the deployed code, as well as any dependencies like system libraries Same for us, but we use nixpkgs directly over CentOS. Nix is perfect for rollback. It can be done on an entire cluster in seconds. For the DB, We use schemaless DBs with Devs that care about forward and backward compatibility.