Kafka vs REST: Why Event Streaming Flips How Services Communicate

A software engineer on DEV Community explains Apache Kafka by contrasting it with the REST API model familiar to most developers. In REST-based systems, the calling service must explicitly know and contact every other service it depends on, creating tight coupling that grows as the business scales. Kafka reverses this by having services publish facts to a shared log, which other services read independently without being directly called. This means adding a new downstream service, such as a loyalty points system, requires no changes to the original publishing service. The article argues that understanding this fundamental shift in responsibility, rather than memorizing Kafka's technical configuration, is the key to grasping why the platform exists.