From Pixels to Pure Derivations: Deterministic Logos with Nix (nixcon2025)

When we think of reproducibility, we often focus on software builds, but what about the logos and visuals that represent our projects? In this talk, I’ll share how I approached logo design for the NixOS project with the same rigor we apply to software: deterministic outputs, minimal storage overhead, and fully free tooling. I’ll discuss the journey of building my own FOSS tooling to generate NixOS logos as SVGs from source code. Existing tools like Inkscape or Blender were either not parametric enough or not designed for clean, annotated vector outputs. By combining principles of CAD, typography, and color theory, I created a pipeline for reproducible, fixed-output derivations (FODs) that ensure all branding assets are versioned, verifiable, and easy to regenerate. This talk will cover: 1. The challenges of finding FOSS tools for parametric logo design. 2. Deep dives into fonts, kerning, and color spaces to build a consistent design language. 3. How I integrated FODs with verification tooling to ensure logo correctness. 4. Lessons learned about repository hygiene and why developers should expose overlays and NixOS modules rather than forcing consumers to hack around flake outputs. about this event: https://talks.nixcon.org/nixcon-2025/talk/HWQRXK/