I Guess I'm a Nix User Now

Two weeks ago I volunteered on the Tech Team for Scale 23x, which is, according to the website, "North America's largest community-run open source conference."

It was a blast: I attended talks, learned some networking, contributed to the software stack that powers the network that conference attendees rely on, and had a great time with friends.

There are so many passionate people out there doing fascinating and incredible work, and Scale tends to attract people who are interested in things as opposed to merely doing work for their jobs (no shame in the latter, of course). On the whole, it was an enjoyable, enlightening, exhausting week and yesterday Mike and I published an episode about our experiences.

But there were two technical themes I took away from my week at Scale:

• AI stuff invading all the spaces
• Nix

This post is about the latter because volunteering at the conference converted me into a Nix user! And of course, like any new convert, I am compelled to evangelize! (Half-joking there: did you know I used to write Haskell...?)

The NixOS Lure

For context, the networking stack (indeed, all the software) that runs Scale is open-source, and the scale-network repo includes detailed instructions on setting up the servers, routers, switches, and access-points that the networking team runs in order to enable internet access for conference attendees, speakers, and the apps that run the conf. To the best of their ability they prioritize open-source, linux-based tools, but in some cases they have to compromise and use closed-source proprietary technologies, often due to the time, effort, and/or cost of trying to swap out open-source alternatives.

The scale-network repo specifically is organized primarily as a Nix configuration, and in order to contribute to their codebase, Rob Hernandez (who leads the Scale Tech Team) handed me an old Thinkpad, leaving me with the following instructions: get a NixOS iso on a usb stick, install NixOS, and fork our repo. So that's what I did.

Now, NixOS is a thin wrapper around Linux, but one confusing thing about Nix is that it represents three different things which can work together:

• Nix Packages: the package manager.
• Nix the programming language: a functional programming language used to write nix configurations, instructions for installing packages and configuring machines.
• NixOS: a Linux operating system which comes pre-integrated with the above.

So then starting just before the conference and for the first days there, I was running a Linux machine with NixOS, which I could use to modify and test changes to their codebase.

Fast Feedback Configuration Changes

Almost instantly after booting into NixOS and deciding I needed to make changes, I was finding myself running through this fast-feedback loop:

• Modify nix configuration
• run nixos-rebuild switch
• check if the new configuration is how I wanted it (or rollback with one command)

Now, I've configured so many machines for software development over the years. I've written Ansible, Saltstack, Terraform, CloudFormation, godawful hand-coded shell scripts and other junk, some Azure biz, and various other things I'm forgetting in order to configure cloud machines. By contrast, when it comes to personal machines, my "process" has been entirely nonexistent. These infrequent attempts are all fuzzy, manual and really based on my entirely fallible memory as I try to muddle through various clickings and typings and whatever who knows what else to get back to some semblance of a development machine that feels vaguely familiar.

In short, compared with my hand-rolled, relying-on-memory crap, the NixOS feedback loop is incredible.

I was shocked: You're telling me I can install things and I don't need to modify $PATH or figure out where they landed?! You're telling me I can try stuff out without committing to installing it on my machine?! You're telling me that every time I boot, any garbage I've manually added via homebrew or whatever is magically cleared away?!

This is incredible.

Write Once, Run Everywhere

The promise of writing a single configuration file (or one broken up pragmatically into smaller modules), even at the cost of learning the Nix programming language, is intoxicating.

I was hooked. So much so that I just purchased my first new personal computer in 22 years. All this time I've just been using whatever work machine I was given, but after the conference my new goal became: "buy a machine. use Nix from the start."

So I did just that (see photo at top).

Originally, I was thinking about getting a Linux machine but I've been using Macbook Pros for 15+ years, so I'm pretty spoiled by the screens and the keyboards and the solid feel of things. I briefly looked at Framework and Tuxdeo and a few others and while they do look pretty nice, and I'd be fine with running Linux, I couldn't guarantee that I would love the screens and keyboards and I was too shy to shell out cash for something I wasn't sure I'd love. What I really needed was a way to demo these machines for a few weeks to see if they'd work for me.

But I didn't have a few weeks; I needed to get a personal machine running Nix now.

Nix-Darwin

So I bought a Macbook Pro.

Now, before you judge me for being a spendthrift mercedes-computer shopper, keep in mind what I mentioned above: I haven't bought a new computer since 2004, so I guess I'm saying I'm due.

Running OSX meant no NixOS, but I can still run the Nix package manager and configure my system using the Nix programming language, benefits provided by the open-source nix-darwin project.

But it's still so rad: you can turn off the system bell when the machine boots, you can programmatically set your dock, Mission Control, spaces, touchpad gestures, terminal programs, GUI programs, homebrew, and thousands of other features all using a single configuration file (or multiple if that's your flavor).

And here's the most amazing part: write it one time, use it forever. Use it on one machine or thousands of machines. No more manual, fallible-memory based configurations!

It did take some work (and, full transparency, a little help from Claude Code), but I put all of my configurations into my dotfiles repo, where I am going to use them to set up a new work machine also.

And the Nix Community Is Massive

Lastly, there are some really high shoulders we also get to lever ourselves up on here: the nix-darwin project, the Nix community, and Nix packages the largest collection of packages in the world.

Want to install Signal and Ghostty and automatically have them land on your dock on a new machine? You can do that.

The Nix community is what makes all of this possible: everything is right there at your fingertips ready to be added to your configuration!

I'm never going back.