Why does EDA reduce coupling between services?

EDA (event-driven architecture) reduces coupling between services because services do not talk to each other directly, but interact through events passed through a message broker.

#1. No direct dependencies

The publisher of an event ("OrderCreated") does not know who will receive it or how they will react. It just publishes the fact: the infrastructure does the rest. This removes direct calls like REST requests and eliminates dependency on other services' APIs.

#2. Subscriber flexibility

Subscribers can change, be added, or be removed without changing the publisher's code. For example, an analytics or notification service can later be attached to the "payment completed" event: the other services will not notice.

#3. Isolated development

Each service evolves independently: its own logic, data schema, language, update frequency. The only contract is the structure of the event.

#4. Buffering and resilience

The message broker accepts events even if a consumer is temporarily unavailable, removing the rigid synchronous "sender → receiver" dependency.

Summary:

In EDA, services are connected through events, not directly, so each of them is autonomous, easily replaceable, and does not break the others when changes happen.