The choice between event-driven and REST architectures is one of the most consequential decisions in system design. Here's how to make it intentionally.
When REST Wins
REST is the right choice for synchronous, request-response interactions where the caller needs an immediate answer. CRUD operations, read-heavy APIs, and integrations where the consumer controls the timing are natural REST use cases.
When Event-Driven Wins
Event-driven architectures shine when you need loose coupling between systems, when multiple consumers need to react to the same business events, or when processing can be asynchronous. The message queue absorbs spikes that would overwhelm synchronous APIs, providing natural backpressure that keeps systems stable under load.