RTS Questionnaire · Question 45 of 52 · file: answers/q45.html
Have you designed systems involving service-to-service communication, API gateways, authentication, service discovery, messaging, and distributed processing?
MicroservicesAPI GatewayMessaging
✅ Yes — these are the standard building blocks of the distributed systems I design.
🧪 Interactive proof: this answer has its own page with a live service-fabric workflow, the gateway policy, the identity handler and the consumer-group topology behind it — open the Q45 service-fabric proof →
Technical detail
- 🔗 Service-to-service communication — synchronous REST/HTTP with typed clients, timeouts and retry policies (
IHttpClientFactory+ Polly, Feign/WebClient on Spring), gRPC where latency/throughput matter, and asynchronous messaging (Kafka, RabbitMQ, ActiveMQ/JMS, SQS/SNS, Azure Service Bus) for decoupled workflows. - 🚪 API gateways — AWS API Gateway, Azure API Management, Ocelot/YARP-style gateways and reverse proxies for routing, authentication offloading, rate limiting, request/response transformation, canary routing and centralised observability.
- 🔐 Authentication and authorization — OAuth2/OIDC at the edge with JWT propagation between services, client-credentials and mTLS for internal calls, scoped permissions per service, API keys for partners, and secrets in Key Vault/Secrets Manager.
- 🧭 Service discovery and resilience — DNS-based discovery via Kubernetes Services, Consul/Eureka-style registries in earlier stacks, client-side load balancing, health checks, circuit breakers, bulkheads and graceful degradation when a dependency is unhealthy.
- 📨 Distributed processing — partitions and consumer groups for parallel throughput, ordering guarantees where required, idempotent consumers, DLQs and replay, plus workflow orchestration (Step Functions/sagas) for multi-step processes.
🔍 All of it is observable: correlation IDs propagated across hops, distributed tracing, metrics per endpoint/queue and alerting on error budgets.
🧾 CV evidence: CV: API Gateway and microservices with Python/Lambda, AWS EventBridge/Step Functions/SQS/SNS, Azure Service Bus + Logic Apps + API Management hybrid integration assessment, Oracle Service Bus proxy/orchestration experience.