I remember Target funded some earlier Nix work like lorri.
Interestingly, I found operating at this level to have been a necessity if I wanted to fix or write a derivation. Otherwise I would face random errors and be left clueless as to what the problem was.
Writing a derivation builder (nix pill) was illuminating.
That was a really special team. Nobody "let" me use Nix, we just did it because it made sense to us, and I went out of my way to support it internally not because I felt pressured to do it, but because I was enthusiastic about making it work. The culture there reminded me of this story[1] about getting Python into production at Goldman—and it turns out that the VP who built the supply chain team at Target started his career in strats at Goldman and was heavily inspired by the same Armen from that story :)
[1]: https://news.ycombinator.com/item?id=29104401
After leaving Target, I also used Nix for my own work setup at CX Score. That was a seed-stage startup and I didn't want to push Nix on anybody else, but it made my own work setup much nicer.
Most recently I moved to Mercury where we use Nix at a pretty big scale (several hundred developers). We have a team that handles most of it so I haven't had to do much myself, but I've helped a few people work through Nix issues just because I could :) I'm also one of the weirdos who uses NixOS on my work laptop instead of getting a macbook.
And, in parallel, I've been using NixOS on all my personal machines ever since I first discovered it. That was relatively shortly before joining Target, so, if I had to guess, late 2015 or early 2016. Coming up on 10 years shortly, even though it really does not feel like it...
I love NixOS and was excited to see Mercury using it. What made Mercury choose it and what have the advantages been for a company like that?
The key insight is that it's been able to scale and still work pretty well even as Mercury is hitting a few hundred developers. There's a bit of friction here and there, but the overall dev experience is pretty good; in a number of ways, it's distinctly better than what I've seen in places that heavily use Docker.
It's cool to see some of the most cutting edge infra teams coming around to a tool that came well before Docker.
Since you're presumably using nixos VMs a lot, I'd be curious if you have any thoughts on this project. It's Nix hypervisor + microvms as an alternative to containers
I have used Nix on and off for work since 2018. We are using Nix at my current employer for two projects. I agree that if you want to go beyond some simple dev shells, for any realistically complex project you really need Nix Pills-level understanding (+ a good idea of how things work in nixpkgs).
It's a two-edged sword - the learning curve is very steep, but once you have that level of understanding, it's a superpower. We heavily use CUDA/ROCm machine learning stacks and Nix makes it much easier to ensure everyone is using the same development environment. Switching between different branches that may have different sets of dependencies/dependency versions always works. Also, it's much easier to stack custom patches on dependencies and caching avoids all the rebuilds.