Theo Zourzouvillys — WritingLonger-form essays on engineering, leadership, and life on the water.https://zrz.io/Engineering Field Notes: Writing Down What I'd Otherwise Just Sayhttps://zrz.io/blog/2026-06-engineering-field-notes/https://zrz.io/blog/2026-06-engineering-field-notes/Most of what I know about building software lives in my head and in scattered Slack threads. Field Notes are my attempt to write it down once, carefully — numbered, dated, status-tracked notes on the practices I keep reaching for, published openly so I can point at them instead of retyping them.Thu, 11 Jun 2026 00:00:00 GMTSign the Request, Not the Session: Announcing httpsighttps://zrz.io/blog/2026-06-httpsig/https://zrz.io/blog/2026-06-httpsig/A bearer token is a password you mail to everyone you talk to. HTTP Message Signatures (RFC 9421) sign the request itself instead — provable, per-request, tamper-evident. I built httpsig, a library for it in five languages, and a jwt.io-style playground you can sign and verify in right now, in your browser.Fri, 05 Jun 2026 00:00:00 GMTComox — Low Waterhttps://zrz.io/blog/2026-06-comox-low-water/https://zrz.io/blog/2026-06-comox-low-water/Logbook: tied up at low tide in Comox Harbour.Tue, 02 Jun 2026 00:00:00 GMTLet the Machine Draw It: Using AI to Visualize Algorithmshttps://zrz.io/blog/2026-06-visualizing-algorithms-with-ai/https://zrz.io/blog/2026-06-visualizing-algorithms-with-ai/I had a rolling-canary routing algorithm sketched on a whiteboard. Twenty minutes of conversation later I had an interactive emulator I could scrub through. Why building throwaway visualizations is one of the highest-leverage things you can do with an LLM.Tue, 02 Jun 2026 00:00:00 GMTContext Is King: Human Language in Code Matters More Than Everhttps://zrz.io/blog/2026-05-context-is-king/https://zrz.io/blog/2026-05-context-is-king/Code is the what; comments, commit messages, and PR descriptions are the why. Why the LLM era makes writing down context non-negotiable.Thu, 28 May 2026 00:00:00 GMTUnderstanding Navionics Accuracy and Limitations in Marine Navigationhttps://zrz.io/blog/2024-12-navionics-accuracy-inside-passage/https://zrz.io/blog/2024-12-navionics-accuracy-inside-passage/Why "Navionics is inaccurate" usually isn't the app or the charts — it's your GPS source. Reading chart data quality (ZOC) and getting reliable positioning in the Inside Passage.Thu, 12 Dec 2024 00:00:00 GMT