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Cover image for EVENT-DRIVEN ARCHITECTURE (EDA)
Aman Verma
Aman Verma

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EVENT-DRIVEN ARCHITECTURE (EDA)

▶ What is EDA?

  • A software architecture where systems communicate using events.
  • An event signals that something important happened (e.g., order placed, ride requested, video paused).
  • Services react to events instead of calling each other directly.

▶ Why EDA is Needed

  • Traditional request–response causes tight coupling.
  • As services grow, connections become complex and hard to scale.
  • Updating one service can break many others.
  • EDA decouples services, improving scalability and flexibility.

▶ Core Idea

  • Producers create events.
  • Consumers react to events.
  • Communication happens asynchronously via a messaging system.
  • Producers and consumers do NOT know about each other.

▶ Key Components

  • Event Producer: generates events.
  • Event Consumer: processes events.
  • Event Broker: routes events (queue/stream).
  • Event Contract: defines event structure and data.

▶ Real-World Examples

  • Streaming platforms track user actions as events (play, pause, rate) for recommendations and analytics.
  • Ride-sharing apps use events for matching drivers, pricing, ETA calculation, and traffic updates.
  • Multiple services consume the same event independently.

▶ EDA vs Service Mesh

  • EDA: asynchronous, event-based communication.
  • Service Mesh: synchronous service-to-service communication.
  • Both patterns often work together in microservices systems.

▶ Event Processing Types
1) Simple Event Processing

  • One event → one direct action.
  • Example: Order placed → update inventory.

2) Complex Event Processing

  • Multiple events analyzed together.
  • Example: Demand + traffic + drivers → surge pricing.

▶ Benefits of EDA

  • High scalability.
  • Independent service scaling.
  • Better fault tolerance.
  • Efficient real-time data processing.

▶ Challenges of EDA

  • Event ordering can be difficult.
  • Risk of duplicate event processing.
  • Eventual consistency instead of immediate consistency.
  • Requires careful design and monitoring.

▶ Common Tools

  • Distributed streaming platforms for high-scale events.
  • Cloud-based messaging services.
  • Lightweight brokers for smaller systems.

▶ Final Takeaway

  • EDA is not just a trend.
  • It powers modern systems that process billions of events daily.
  • Essential for scalable, real-time, microservices architectures.

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