Event Driven Architecture
When you place an order on Amazon, a lot happens in the background:
- The Inventory Service reduces stock.
- The Payment Service charges your card.
- The Notification Service sends a confirmation email.
- The Analytics Service logs the order event for insights.
None of these systems talk to each other directly — instead, they react to a single OrderCreated event. That’s the power of Event-Driven Architecture (EDA).
In EDA, components react to events asynchronously. Instead of constantly polling or waiting for data, components simply “listen” for events and act when they occur. This approach leads to systems that are more modular, scalable, and responsive.
In this chapter, we will deconstruct EDA, explaining what it is, how it works, and why it has become the backbone of modern, scalable, and resilient applications.