Event-driven architecture (EDA) uses small, decoupled services that publish and consume events representing state changes, like an order shipping. Unlike request-driven models, EDA promotes loose coupling, making systems easier to scale and update independently.

AWS offers key messaging services to build these systems. Amazon SQS provides managed queues for decoupling components, with standard and FIFO options. Amazon SNS handles pub/sub messaging, pushing one message to multiple subscribers like SQS or Lambda.

Amazon EventBridge acts as a serverless event bus, routing events between services and applications. For implementation, a common lab involves using SQS with Lambda consumers and dead letter queues for failure handling, demonstrating asynchronous processing in practice.