Event sourcing has a reputation problem. Too often, it's presented as an advanced architectural pattern reserved for complex enterprise systems, wrapped in academic language that makes it feel inaccessible. We built eventsourcing.dev to change that.
Event sourcing is a practical, powerful approach to building systems. It deserves a practical, powerful guide.
Why We Built This
As the team behind GenesisDB, we spend a lot of time talking to developers about event sourcing. The same questions come up repeatedly: What exactly is an event? How do I model my domain? When should I use snapshots? What's the difference between event sourcing and event-driven architecture?
Existing resources often fall into two camps: either too theoretical and abstract, or too tied to specific frameworks and technologies. We wanted something different: a vendor-neutral, comprehensive guide that starts from first principles and builds toward production-ready patterns.
What You'll Find
The guide is organized into two main sections designed to take you from foundational concepts to real-world implementation.
First Principles
Before diving into patterns and best practices, you need solid foundations. This section covers:
- Event Types How to design events that accurately represent what happened in your domain
- Subjects Modeling the entities and aggregates that events happen to
- Sources Identifying where events originate in your system
- CloudEvents The standard specification for describing events in a common way
- Snapshots Optimizing event replay performance for long-lived aggregates
Best Practices
Once you understand the fundamentals, these sections help you apply them effectively:
- Modeling Events Naming conventions, granularity decisions, and payload design
- Event Storming Collaborative workshops for discovering domain events with your team
- Designing Aggregates Building effective consistency boundaries that scale
- Dynamic Consistency Boundaries Managing consistency across distributed systems
The Core Benefits
Event sourcing isn't just a different way to store data. It fundamentally changes what's possible with your system:
Complete Audit Trail
Every state change is recorded as an immutable event. You get full history and accountability built into your data model, not bolted on as an afterthought.
Time Travel
Need to know what your system looked like last Tuesday at 3pm? Replay events up to that point. Debug production issues by reconstructing exact historical state.
Event Replay
Made a mistake in your read model projection? Fix the code and replay from the beginning. Your events are the source of truth; everything else can be rebuilt.
Event Stores vs Traditional Databases
The guide also covers infrastructure considerations, including why purpose-built event stores exist. While you can implement event sourcing on top of traditional relational databases, dedicated event stores offer:
- Append-only optimization for write-heavy workloads
- Native concurrency control with optimistic locking
- Stream-native queries designed for event access patterns
- Built-in support for subscriptions and real-time projections
The right choice depends on your scale, team experience, and requirements. The guide helps you make an informed decision.
A Growing Resource Collection
Beyond the guides and tutorials, we've also compiled a growing list of resources to help you on your event sourcing journey. This includes libraries, frameworks, event sourcing database systems, and tools across different languages and platforms.
Whether you're looking for a TypeScript library, a Java framework, or exploring different event store options, the resources section provides a curated starting point. And if you know of something we've missed, we welcome contributions from the community.
Closing Thoughts
Event sourcing has been around for decades, but it's never been more relevant. As systems become more distributed, as compliance requirements grow stricter, and as debugging distributed systems becomes more challenging, the benefits of an append-only, auditable event log become clearer.
We hope eventsourcing.dev removes the barriers to getting started. Whether you're evaluating event sourcing for the first time or looking to refine your existing implementation, the guide is here to help.