Event-driven is about having modules which are communicating via messages (events and commands). There's nothing that forces you to go microservices if you want to go event-driven. In fact, it's actually not needed in most cases. Learn more at http://railsarchitects.com

1. Andrzej Krzywda, Arkency
Event-driven
without
microservices

2. Event-driven requires modules
and events

3. Modules can be deployed as
microservices but in most cases it’s
overkill 😎

4. You can be event-driven in a
monolithic server

5. A monolith with modules is called
a modulith

6. Modulith is the way to go
unless you really have strong arguments for the
microservices overhead

7. In short:
Event-driven is orthogonal to microservices

8. 2 different decisions

9. You can go microservices without going event-driven
But that’s the worst possible choice 😂

10. You can go event-driven within one modulith
Best choice 💰

11. What about event stores or message buses?
Do we need external tools like Kafka or RabbitMQ?
NO 😡
In most cases that’s an overkill

12. All you need is some way of:
• publishing events (in memory)
• storing events (in db tables is fine)

13. RailsEventStore is exactly this
• Keeps events and streams in relational db (postgres is great,
mysql too)
• Helps with publishing events

14. Conclusion
• Don’t go for microservices
• Build a modulith
• Go event-driven and decouple modules
• Enjoy a simple infrastructure and great modularity