Engineer · Speaker · Nebraska
About
I'm Erik Shafer, a backend software engineer and consultant based in Nebraska. I specialize in .NET, with a focus on domain modeling and event-driven systems: event sourcing, CQRS, and message-driven architectures.
I'm a Senior Consultant at Improving and a member of the JasperFx core team, which builds the Critter Stack. That includes the open-source libraries Marten and Polecat (document database and event store on PostgreSQL and SQL Server, respectively), along with Wolverine (messaging and HTTP) and Alba (integration testing), plus CritterWatch, a console for monitoring and managing them in production.
Append Only is this site. The name is a nod to the event log — the append-only data structure at the heart of event sourcing.
I speak at conferences and user groups about software architecture, event sourcing, and the Critter Stack, most recently at KCDC 2026 (Kansas City Developer Conference). The full list of talks is on the Speaking page. If you'd like me at your event, get in touch below.
I write about .NET, event sourcing, and software design on the blog, which also holds the posts from my earlier site, event-sourcing.dev.