Microservices Interview Questions and Answers

Explore alternatives to monolithic applications, including component-based libraries, service oriented architecture, and microservices, with focus on independent services, api communication, asynchronous messaging, and diverse technology stacks.

Understand how microservices relate to business goals by using cloud pay-as-you-go models and managed Kubernetes with AWS, Azure, and Google Cloud Platform to enable agile, faster outsourcing while protecting IP.

Idempotence is a concept, not a design pattern, ensuring the same output for the same input to improve microservice resiliency. Track messages with a unique identifier to prevent duplicates.

discover how api composition lets you fetch data from multiple microservices by querying each service, joining results in memory, and returning a unified response via an api composer microservice.

Apply the strangler pattern to migrate legacy monoliths to microservices by incrementally replacing functionality while the system stays live.

Explain how independent microservices communicate, comparing synchronous point-to-point API calls with event-based messaging via event streams like Apache Kafka and message queues such as ActiveMQ or RabbitMQ.

Learn the two-phase commit pattern, with prepare and commit phases coordinated by a transaction ID, where microservices prepare, then commit, and failures trigger abort.

Explain the choreography pattern for distributed transactions, where an order microservice emits an order created event and a customer microservice updates funds with eventual compensation if needed.

Apply the circuit breaker pattern to api calls by placing a proxy breaker between client and supplier, enforcing open, half-open, and closed states with a three-failure threshold and backoff retries.

OAuth enables open authentication by using a trusted provider as the source of truth. It uses scopes and claims to control access, allowing a single token to authorize multiple microservices.

Explore four security testing approaches for microservices: dust (dynamic application security testing), sast (static), yast (interactive), and rasp (runtime application security protocol) with real-time checks and region-based ip control.

Explore how authentication and authorization secure microservices using OAuth 2 and JWT tokens, including scopes, authorization servers, and token validation via an API gateway.

Master semantic monitoring by validating end-to-end business transactions across microservices through functional testing. Compare service layer monitoring, health endpoints, and telemetry to ensure the whole system performs as expected.

Explore the sidecar pattern for resiliency and cleaner design by isolating auxiliary functions, like logging and configuration, in a separate process shared across microservices.

Explore the service mesh pattern as a dedicated infrastructure layer that manages service-to-service communication with traffic routing, security, observability, and resilience via sidecar proxies, without changing application code.

Explain the transactional outbox pattern: write events to an outbox table within a transaction with read committed, then a relay service publishes only committed, ordered events to the message broker.

Explore how microservices avoid local state by offloading data to a shared Redis cache, enabling resilience as containers scale out and terminate in cloud environments.