Ash Hatz — WritingNotes by Ash Hatz on software, AI, runtimes, public transport, urbanism, and the things in between.https://ashhatz.com/en-gbThe runtime is the city: what software can learn from how London actually moveshttps://ashhatz.com/writing/runtime-is-the-city/https://ashhatz.com/writing/runtime-is-the-city/Mon, 20 Apr 2026 00:00:00 GMTUrbanismWhy I think 'AI-native' is mostly a story about latency, not intelligencehttps://ashhatz.com/writing/ai-native-is-about-latency/https://ashhatz.com/writing/ai-native-is-about-latency/Sun, 12 Apr 2026 00:00:00 GMTSoftwareBuilding Planda, six months in: lessons from putting paper forms on railshttps://ashhatz.com/writing/building-planda-six-months/https://ashhatz.com/writing/building-planda-six-months/Sat, 28 Mar 2026 00:00:00 GMTBuilding PlandaOn distributed systems, public transport, and the strange comfort of a timetable that's almost righthttps://ashhatz.com/writing/distributed-systems-and-the-timetable/https://ashhatz.com/writing/distributed-systems-and-the-timetable/Wed, 04 Mar 2026 00:00:00 GMTPublic TransportThe Bakerloo line as a case study in technical debthttps://ashhatz.com/writing/bakerloo-line-technical-debt/https://ashhatz.com/writing/bakerloo-line-technical-debt/Sat, 14 Feb 2026 00:00:00 GMTPublic TransportCities are runtimes that refuse to restart, and that's the most interesting thing about themhttps://ashhatz.com/writing/cities-are-runtimes/https://ashhatz.com/writing/cities-are-runtimes/Thu, 22 Jan 2026 00:00:00 GMTUrbanismWhat I want from an AI assistant in 2027 (and why most of the current ones get it wrong)https://ashhatz.com/writing/what-i-want-from-ai-assistant-2027/https://ashhatz.com/writing/what-i-want-from-ai-assistant-2027/Mon, 15 Dec 2025 00:00:00 GMTSoftwareA small case for boring infrastructure, and a slightly larger one for the people who maintain ithttps://ashhatz.com/writing/boring-infrastructure/https://ashhatz.com/writing/boring-infrastructure/Tue, 02 Dec 2025 00:00:00 GMTSoftwareHow I read papers now, with the help of a large language model and a lot of suspicionhttps://ashhatz.com/writing/how-i-read-papers-now/https://ashhatz.com/writing/how-i-read-papers-now/Tue, 28 Oct 2025 00:00:00 GMTSoftwareOn reading London like a codebase: a slow walk through the Lea Valleyhttps://ashhatz.com/writing/reading-london-like-a-codebase/https://ashhatz.com/writing/reading-london-like-a-codebase/Thu, 09 Oct 2025 00:00:00 GMTUrbanismSome honest mistakes I've made designing APIs that other engineers had to usehttps://ashhatz.com/writing/honest-mistakes-api-design/https://ashhatz.com/writing/honest-mistakes-api-design/Thu, 04 Sep 2025 00:00:00 GMTSoftware