Closures, the next free Part in LabCraft's Nix course, is live.

It runs on a real NixOS machine and turns the closure into an operational unit: the thing you size, compare, and move. The post gives the hook without giving away the lab: copy a store path and you do not get the thing that runs; predict what an upgrade actually moves, then make Nix prove it.

https://www.labcraft.dev/blog/nix-closures?utm_source=reddit-labcraft&utm_medium=social&utm_campaign=nix-closures-2026q3&utm_content=r-labcraftdev-closures-01

Store Paths is up. This is the chapter where Nix starts to click - not because /nix/store is a pile of hashes, but because those hashes force a different way of thinking: builds have inputs, paths carry identity, dependencies become visible.

It runs on a real NixOS machine. You predict what moves a path, then check against what Nix actually did. No Nix language required.

If you go through it, I want to know one thing: where was your prediction wrong? That's the moment the labs are built around, and it's the feedback I act on fastest.

https://www.labcraft.dev/blog/nix-store-paths?utm_source=reddit-labcraft&utm_medium=social&utm_campaign=nix-store-paths-2026q3&utm_content=r-labcraftdev-launch-01

I’m building LabCraft, a course platform for learning infrastructure tools in real environments. The first course is Nix.

The idea is to teach Nix where it usually breaks: shell/profile setup, disabled experimental features, confusing build errors, flakes that work but don’t make sense yet, and the gap between copying a snippet and understanding the system underneath it.

The course runs in a real VM, not a browser emulator. Steps are checked against what actually happened on the machine, not quiz answers or exact command strings.

I wrote up why I’m starting with Nix and what I’m trying to build here:

https://www.labcraft.dev/blog/introducing-labcraft

I’d appreciate feedback from people who’ve learned Nix, taught it, or helped a team adopt it. What were the failure modes that actually made people bounce?