Use REST for broadly interoperable request/response APIs, gRPC for strongly typed low-latency service calls and streaming, and messaging when producers should not wait for consumers or services need temporal decoupling. The choice is per interaction, not per system. A checkout can accept REST, call an internal pricing service with gRPC, and publish OrderPlaced through a broker. Messaging introduces eventual consistency, duplicates, ordering questions, and operational overhead, so consumers must be idempotent and messages observable. Define timeouts, retries only for transient/idempotent operations, schema compatibility, authentication, and ownership. Do not use a broker to hide an unclear synchronous business dependency.
Backbencher Developer · · 0 likes