SE Radio 720: Martin Dilger on Understanding Eventsourcing

In this episode of Software Engineering Radio, host Giovanni Asproni interviews Martin Dilger, founder and CEO of Nebwilt GmbH and author of 'Understanding Event Sourcing,' about the principles, benefits, and practical implementation of event sourcing in software development. Dilger emphasizes that event sourcing is not just a technical pattern but a mindset shift toward modeling systems through business processes and events—facts that have happened—rather than CRUD-based data structures. He explains how event modeling, particularly through collaborative workshops, helps teams align on a shared language and build systems that are easier to understand, evolve, and maintain. The discussion covers core patterns like state change and state view slices, the role of projections and read models, and how event sourcing preserves the dimension of time by storing full history. Dilger also addresses common misconceptions, such as using Kafka as an event store (which he warns against), and argues that event sourcing should be the default approach for most systems, not a niche solution. He highlights tangible benefits like flat cost curves, improved testability via behavior-driven development, and faster time-to-market, especially when combined with AI-assisted development. Practical advice includes starting with event modeling workshops, building proof-of-concept systems incrementally, and measuring success through 'slice cycle time.' The episode concludes with a strong endorsement for teams to try event sourcing through low-risk experiments like 'FedEx days'—one-day sprints to deliver working software. Dilger stresses that the real value lies not just in the technology but in the collaborative process, which reduces coupling, prevents costly late-stage changes, and enables continuous delivery. He shares real-world experiences from modernizing legacy systems using AI to reverse-engineer event models from code and UI, demonstrating how event sourcing can unlock hidden knowledge in aging systems. Overall, the conversation paints event sourcing as a transformative, human-centered approach to software design that aligns technical architecture with business reality, leading to more resilient, agile, and sustainable systems.