Hi! I'm Luiz, a software engineer originally from Brazil and now based in the US.
After a long career in big tech, I stepped away to build things on my own terms. These days I'm exploring where AI agents, virtualization and infrastructure meet. I care about local-first software, declarative systems, and tools that keep your data private by default. I'm especially interested in how strong primitives like VMs and WebAssembly sandboxes can let autonomous tools do useful work while users stay in control.
I write about what I'm building at l9o.dev.
Some projects I maintain:
- uptix: pins and updates external dependencies, like Docker images, in NixOS configurations.
- agentix: a single Nix flake for popular AI coding CLIs.
- weblounge.org: a small, invite-only IRC network. If you'd like an invite, send me an email.
Coming soon: wasm-junction, an ergonomic Rust framework for building applications out of WebAssembly components. It runs natively on Wasmtime and in the browser. It's still early and the API isn't stable yet.
When something I depend on breaks, I try to fix it upstream. Recently that has meant macOS support for microvm.nix through the vfkit hypervisor, plus fixes in jco, russh and nixpkgs.
- Thou shall only ping once (Dec 2025)
- Remote Code Execution on the Siglent SDS1104X-E (Dec 2025)
- Controlling an Elegoo Mars Pro remotely (Oct 2020)
I spent 13 years at Facebook and Instagram, slowly working my way down the stack. I started in web frontend, on one of the first teams to run React in production, and ended up in privacy infrastructure that helps thousands of engineers handle user data responsibly.
Some past projects I'm no longer maintaining:
- mariner: a web interface for MSLA resin 3D printers based on Chitu controllers (Elegoo, Phrozen). It started as a Raspberry Pi Zero wired to my printer's serial port (writeup).
- vim-cooklang and py-cooklang: a vim plugin and a Python parser for Cooklang, a markup language for recipes.
- gython: a Jython fork with operators for manipulating graphs, built as part of the Gephi Scripting Plugin for Google Summer of Code 2011.
- QMK: I added support for ps2avrGB keyboards to the keyboard firmware.
I like building things with my hands: 3D printing, CNC machining and electronics. I'm a bit obsessed with home automation. I've loved space since I was a kid, and I photograph the night sky from Bortle 9 skies near NYC. Occasionally I find bugs in my lab equipment too, like a remote code execution on my oscilloscope.