Event-Driven Architecture

Event-driven architecture, or EDA, organizes work around events: records that state a fact has occurred. An order was placed. A payment was accepted. A device reported a reading. The component that records the fact is the producer. Components that react to it are consumers.

The key shift is time. In a request-response call, the caller waits for a specific handler. In EDA, a producer publishes an event to a channel and can continue. Consumers process it independently. This reduces direct runtime coupling and lets one event support several reactions, such as sending a receipt, reserving inventory, updating analytics, and starting fulfillment.

A broker or event log often carries events between producers and consumers. The transport is not the architecture. The architecture is the contract: what an event means, who owns it, how it is delivered, and what a consumer must do when it arrives late, twice, or in a new version.