Tutorial: 10:05-11:35 (English)

Event in, events out?

Using event sourcing strategies can be a nice way to enable some decoupling. However when interacting with external systems one should watch out how much of the internal objects leak through to the api.

Event sourcing is an architecture that brings a couple of benefits compared to crud applications. It becomes easier to model complex domains. Also because events are the only way to change data, and the events are always stored, there is a clear audit trail.

Using GraphQL for the api enables streaming which could be very nice when working with events. But it also allows you to design specific types, and even gracefully deprecate when needed.

We will work on example which is easy to setup with docker, and continue to make modifications to the model to add new features.


Instructions for running the tutorial code is here:


Gerard Klijs


With roots in Java Web development the last years I’ve versified, working on streaming systems, GraphQL, and also been busy with Clojure, Rust and Kotlin. Some of those things ended up as open source to be used by others.