eventsdriven

Event-driven, or eventsdriven, refers to a software design in which the flow of the program is determined by events—signals that something has occurred. The term covers two related concepts: event-driven programming within a single application and event-driven architecture across distributed systems. In both cases, components react to events rather than continuously polling for state changes.

Events are produced by sources such as user actions, timers, or other parts of the system. They are delivered through channels or brokers and handled by event handlers or listeners. Common mechanisms include publish/subscribe models, callbacks, and event loops that schedule work asynchronously. Decoupling between producers and consumers is a core feature, enabling scalable and flexible compositions.

In practice, event-driven programming is central to graphical user interfaces, where user input drives actions, and to server environments like Node.js and browser runtimes, which rely on an event loop to manage asynchronous I/O. In distributed systems, event-driven architecture uses message brokers (for example, Kafka, RabbitMQ, or cloud services) to route events to interested services, enabling scalable, reactive pipelines and microservices communication.

Advantages include responsiveness, scalability, and loose coupling. Challenges include debugging complexity, potential for event storms, eventual consistency concerns, and the need for careful error handling and tracing across asynchronous boundaries.

Related topics include event-driven programming, event-driven architecture, event sourcing, and message brokers.