Running Untrusted Code in a Multi-Tenant Platform: How Hapnd's Four-Layer Security Model Works
How Hapnd executes customer-supplied C# reducers and projections safely: a walkthrough of the four independent layers that protect the platform.
Event Sourcing
7 posts
Modelling a Subscription Billing Engine with Event Sourcing: A C# Walkthrough
A step-by-step C# walkthrough of modelling a subscription billing engine with event sourcing: aggregates, events, and where the boundaries go.
Five Event Sourcing Pitfalls That Bite You After the Tutorial
Five production realities that event sourcing tutorials skip: honest event design, cross-aggregate projections, versioning, snapshots, and infrastructure.
Event Versioning in Practice: How to Change Your Events Without Breaking Everything
How to evolve event schemas in an immutable event log: the upcasting pattern, versioning decisions, and testing strategy.
From Events to Read Models: The Projection Problem Most Teams Underestimate
What event sourcing tutorials skip: projection rebuilds, schema evolution, cross-aggregate complexity, and what running it properly requires.
The Four Event Sourcing Problems Most Resources Don't Cover Clearly
Four event sourcing problems most resources skip: optimistic concurrency, projection rebuilds, schema evolution, and snapshots.
Event Sourcing Beyond the Tutorial: The Real Problems You Hit When You Build for Production
Everyone teaches you what event sourcing is. Nobody teaches you what happens next. The real engineering problems you hit when you build for production.