REST / gRPC
HTTP/2 · Protobuf · Streaming
Message Queue
Kafka / RabbitMQ · Event‑driven · At‑least‑once
Service Mesh
Istio / Linkerd · mTLS · Traffic control
Synchronous
Request‑response · Timeout · Circuit breaker
Asynchronous
Pub/sub · Eventual consistency · SAGA
Retry & Backoff
Exponential backoff · Idempotency · Dead‑letter
API Versioning
URI / header · Backward compatible · Deprecation
Observability
Metrics (Prometheus) · Logs (ELK) · Alerts