If you're following my ongoing blog post series on event sourcing and have any questions, feel free to ask here or in the post comments.
The question does not have to be about event sourcing. I'm especially happy to answer questions about the F# samples.
Join me in Gembloux, Belgium on 9 June at the Belgian #Java User Group for my Ted Talk on #EventSourcing! Gonna squeeze a year of learnings into 45 minutes (we'll see how that goes).
Details here: https://www.meetup.com/belgian-java-user-group/events/314996280/
In part eight of my event sourcing blog post series, it's time to look at bi-temporal event sourcing. At least we start with the very basics. Why we need it and how it works.
https://www.planetgeek.ch/2026/06/02/event-sourcing-the-not-so-simple-bi-temporal-basics/
It's time for bi-temporal event sourcing in part eight of my event sourcing series. In this post, I'll stick to the basics - at least I hope so. 😅 Bi-temporal event sourcing means that we have two timestamps associated with an event: The first timestamp tells us when the event entered the system, or when...
Приручаем недетерминизм агентных систем
Агентные системы ломаются не на сложных задачах и не на плохих моделях. Главная причина — недетерминизм LLM: температура, апдейты моделей, дрейф мира. Как отлаживать то, что не воспроизводится? Как перезапустить упавший пайплайн не с нуля? Как вообще понять поведение системы, если каждый запуск чуть-чуть другой? Event Sourcing — паттерн, где состояние не снапшот, а иммутабельный лог событий. Недетерминизм он не убирает, но даёт инструменты для работы с ним.
Build your own or use an out-of-the-box event sourcing library. That's the question I tackle in part seven of my event sourcing series:
https://www.planetgeek.ch/2026/05/26/event-sourcing-why-we-built-our-own-library/
I'll look back at our architectural decisions when we started over 10 years ago and how we likely would decide in today's landscape.
During my series on event sourcing, I got a question a couple of times: "Why don't you use an event sourcing library? Why have you built your own kind of library?" So part seven is about the trade-offs of using out-of-the-box libraries versus building your own - even today. When we started When we started...
In the sixth part of my blog post series on event sourcing, we'll take a look at event versioning and migration. I show 4 different approaches with their trade-offs. Today, a deep dive is included into zero downtime migration of event streams.
Event‑sourced systems must evolve, and sooner or later, events need to change. In the sixth part of my series on event sourcing, we are looking at versioning of events (schemas) and whether migrating or keeping all old versions is the way to go. Of course, there are trade-offs involved regarding long-term maintainability and overall simplicity....
Urs Enzler
Ted M. Young
patchlevel
Ismael Celis
Habr
Wouter Naessens