Microservices interview questions

What are microservices and how do they differ from monolithic architecture?

Easy · Microservices, Core Concepts, Fresher

What are the advantages and disadvantages of microservices?

Easy · Microservices, Core Concepts, Fresher

Explain the evolution from SOA (Service-Oriented Architecture) to microservices.

Medium · Microservices, Core Concepts, Senior

What is bounded context in microservices (Domain-Driven Design)?

Hard · Microservices, Core Concepts, Architect

What is loose coupling and high cohesion in microservices?

Medium · Microservices, Core Concepts, Senior

How do you decide service boundaries in microservices?

Hard · Microservices, Core Concepts, Staff

What is the role of API Gateway in microservices?

Medium · Microservices, Core Concepts, Senior

Difference between microservices and serverless architecture.

Medium · Microservices, Core Concepts, Senior

How do you ensure fault isolation in microservices?

Medium · Microservices, Core Concepts, Senior

What are the common challenges in microservices adoption?

Medium · Microservices, Core Concepts, Senior

Explain synchronous vs asynchronous communication in microservices.

Easy · Microservices, Core Concepts, Fresher

What is the role of orchestration vs choreography in microservices?

Hard · Microservices, Core Concepts, Staff

How do you handle versioning of microservices?

Medium · Microservices, Core Concepts, Senior

Difference between vertical and horizontal scaling in microservices.

Easy · Microservices, Core Concepts, Fresher

What is the role of containers (Docker) in microservices?

Easy · Microservices, Core Concepts, Fresher

Explain the concept of service mesh (e.g., Istio, Linkerd).

Hard · Microservices, Core Concepts, Staff

What are common anti-patterns in microservices?

Medium · Microservices, Core Concepts, Senior

How do you handle cross-cutting concerns in microservices?

Medium · Microservices, Core Concepts, Senior

What is the 12-Factor App methodology and how does it apply to microservices?

Medium · Microservices, Core Concepts, Senior

What is the Strangler Fig pattern? How do you use it to migrate from monolith to microservices?

Hard · Microservices, Core Concepts, Architect

Difference between REST, gRPC, and GraphQL in microservices communication.

Medium · Microservices, Service Communication, Senior

How do you secure communication between services?

Medium · Microservices, Service Communication, Senior

Explain idempotency in API design.

Medium · Microservices, Service Communication, Senior

How do you handle backward compatibility in APIs?

Medium · Microservices, Service Communication, Senior

What is API Gateway throttling and rate limiting?

Medium · Microservices, Service Communication, Senior

Explain service discovery in microservices.

Medium · Microservices, Service Communication, Senior

How do you handle distributed transactions in microservices?

Hard · Microservices, Service Communication, Staff

Difference between client-side discovery and server-side discovery.

Medium · Microservices, Service Communication, Senior

Explain the role of load balancers in microservices.

Easy · Microservices, Service Communication, Fresher

What is eventual consistency and why is it important?

Medium · Microservices, Service Communication, Senior

Difference between synchronous API calls and message-driven communication.

Medium · Microservices, Service Communication, Senior

Explain saga pattern in microservices transactions.

Hard · Microservices, Service Communication, Staff

What is compensating transaction in microservices?

Hard · Microservices, Service Communication, Staff

How do you handle retries and backoff in communication failures?

Medium · Microservices, Service Communication, Senior

What are dead-letter queues and their purpose?

Medium · Microservices, Service Communication, Senior

Explain request-response vs publish-subscribe messaging.

Easy · Microservices, Service Communication, Fresher

How do you achieve service-to-service authentication?

Hard · Microservices, Service Communication, Staff

What is the role of service registry (Eureka, Consul, Zookeeper)?

Medium · Microservices, Service Communication, Senior

What are the common API versioning strategies (URL path, header, query param)? What are their trade-offs?

Medium · Microservices, Service Communication, Senior

What is consumer-driven contract testing (Pact)? Why is it important in microservices?

Hard · Microservices, Service Communication, Staff

Explain the circuit breaker pattern with an example.

Hard · Microservices, Resilience, Staff

What is bulkhead pattern in microservices?

Hard · Microservices, Resilience, Staff

Explain rate limiting strategies (token bucket, leaky bucket, fixed/sliding window).

Medium · Microservices, Resilience, Senior

What is the fallback mechanism in microservices?

Medium · Microservices, Resilience, Senior

How do you design microservices for high availability?

Hard · Microservices, Resilience, Staff

Difference between active-active and active-passive deployments.

Medium · Microservices, Resilience, Senior

Explain distributed caching in microservices (Redis, Memcached).

Medium · Microservices, Resilience, Senior

What is CAP theorem and its relevance in microservices?

Hard · Microservices, Resilience, Staff

How do you ensure scalability of stateful services?

Hard · Microservices, Resilience, Staff

What is service throttling and when is it needed?

Medium · Microservices, Resilience, Senior

Explain chaos engineering in microservices resilience testing.

Hard · Microservices, Resilience, Staff

How do you prevent cascading failures in microservices?

Hard · Microservices, Resilience, Staff

What is auto-scaling and how does it work in Kubernetes?

Medium · Microservices, Resilience, Senior

Explain load shedding in microservices.

Hard · Microservices, Resilience, Staff

How do you design microservices for disaster recovery?

Hard · Microservices, Resilience, Architect

What is the role of circuit breakers in Hystrix/Resilience4j?

Medium · Microservices, Resilience, Senior

Explain leader election in distributed systems.

Hard · Microservices, Resilience, Staff

How do you handle hotspots in distributed services?

Hard · Microservices, Resilience, Staff

What are distributed locks and when do you use them?

Hard · Microservices, Resilience, Staff

What is the Timeout pattern? How do you set appropriate timeout values in microservices?

Medium · Microservices, Resilience, Senior

What is database per service pattern?

Medium · Microservices, Data Management, Senior

How do you handle distributed transactions without 2PC?

Hard · Microservices, Data Management, Staff

Explain event sourcing in microservices.

Hard · Microservices, Data Management, Staff

Difference between CQRS and traditional CRUD approach.

Hard · Microservices, Data Management, Staff

How do you achieve data consistency across services?

Hard · Microservices, Data Management, Staff

What is the outbox pattern?

Hard · Microservices, Data Management, Staff

How do you handle schema evolution in microservices?

Medium · Microservices, Data Management, Senior

Difference between polyglot persistence and single DB approach.

Medium · Microservices, Data Management, Senior

What are the challenges of sharing a database between microservices?

Medium · Microservices, Data Management, Senior

Explain eventual consistency with an example.

Medium · Microservices, Data Management, Senior

What is database sharding and its role in microservices?

Hard · Microservices, Data Management, Staff

What is read/write splitting in microservices?

Medium · Microservices, Data Management, Senior

How do you design a reporting service in microservices?

Hard · Microservices, Data Management, Architect

Explain saga orchestration for data consistency.

Hard · Microservices, Data Management, Staff

What is dual-write problem and how to avoid it?

Hard · Microservices, Data Management, Staff

Difference between synchronous replication and asynchronous replication.

Medium · Microservices, Data Management, Senior

How do you handle GDPR compliance in microservices data storage?

Hard · Microservices, Data Management, Architect

What is multi-tenancy in microservices databases?

Hard · Microservices, Data Management, Staff

How do you monitor data integrity across services?

Hard · Microservices, Data Management, Staff

What is Change Data Capture (CDC)? How does it help with data synchronisation across services?

Hard · Microservices, Data Management, Staff

What AWS services are commonly used for microservices architecture?

Easy · Microservices, Cloud & AWS, Fresher

Explain AWS ECS vs EKS for running microservices.

Medium · Microservices, Cloud & AWS, Senior

How does AWS Lambda fit into microservices?

Medium · Microservices, Cloud & AWS, Senior

What is the role of API Gateway in AWS?

Easy · Microservices, Cloud & AWS, Fresher

How do you design event-driven microservices with AWS SQS and SNS?

Medium · Microservices, Cloud & AWS, Senior

Explain AWS DynamoDB vs RDS in microservices use cases.

Medium · Microservices, Cloud & AWS, Senior

What is AWS Step Functions and its role in orchestration?

Medium · Microservices, Cloud & AWS, Senior

How do you handle service discovery in AWS?

Medium · Microservices, Cloud & AWS, Senior

What is AWS App Mesh?

Medium · Microservices, Cloud & AWS, Senior

How do you monitor microservices in AWS (CloudWatch, X-Ray)?

Medium · Microservices, Cloud & AWS, Senior

Explain difference between ECS Fargate and EC2 launch types.

Medium · Microservices, Cloud & AWS, Senior

What is AWS Elastic Beanstalk and how does it compare with ECS/EKS?

Easy · Microservices, Cloud & AWS, Fresher

How do you secure secrets in AWS microservices (Secrets Manager, Parameter Store)?

Medium · Microservices, Cloud & AWS, Senior

Explain CI/CD with AWS CodePipeline and CodeBuild for microservices.

Medium · Microservices, Cloud & AWS, Senior

What is AWS EventBridge and its role in microservices?

Medium · Microservices, Cloud & AWS, Senior

How do you implement blue-green deployment in AWS?

Medium · Microservices, Cloud & AWS, Senior

Explain canary deployments in AWS using CodeDeploy.

Medium · Microservices, Cloud & AWS, Senior

What is VPC and how does networking work in AWS microservices?

Hard · Microservices, Cloud & AWS, Architect

How do you handle inter-region communication in AWS microservices?

Hard · Microservices, Cloud & AWS, Architect

What are AWS Well-Architected Framework principles for microservices?

Medium · Microservices, Cloud & AWS, Architect

What is observability in microservices?

Easy · Microservices, Observability, Fresher

Difference between logging, monitoring, and tracing.

Easy · Microservices, Observability, Fresher

How do you implement distributed tracing in microservices?

Medium · Microservices, Observability, Senior

What are common tools for monitoring microservices (Prometheus, Grafana, ELK)?

Easy · Microservices, Observability, Fresher

Explain log aggregation in microservices.

Medium · Microservices, Observability, Senior

How do you implement correlation IDs for tracing requests?

Medium · Microservices, Observability, Senior

What is OpenTelemetry and its role in microservices?

Medium · Microservices, Observability, Senior

Difference between white-box and black-box monitoring.

Easy · Microservices, Observability, Fresher

How do you monitor SLAs, SLOs, and SLIs in microservices?

Medium · Microservices, Observability, Senior

What is the role of health checks in microservices monitoring?

Easy · Microservices, Observability, Fresher

How do you implement metrics collection in microservices?

Medium · Microservices, Observability, Senior

Explain anomaly detection in microservices logs.

Hard · Microservices, Observability, Staff

What is centralized logging and why is it important?

Easy · Microservices, Observability, Fresher

How do you set up alerts and dashboards for microservices?

Medium · Microservices, Observability, Senior

What are common tracing tools (Jaeger, Zipkin)?

Easy · Microservices, Observability, Fresher

Explain proactive vs reactive monitoring.

Medium · Microservices, Observability, Senior

What is log correlation in distributed systems?

Medium · Microservices, Observability, Senior

How do you monitor resource usage in Kubernetes microservices?

Medium · Microservices, Observability, Senior

What is synthetic monitoring?

Easy · Microservices, Observability, Fresher

How do you perform root cause analysis in microservices failures?

Hard · Microservices, Observability, Staff

How do you secure microservices communication?

Medium · Microservices, Security, Senior

What is OAuth2 and how is it used in microservices?

Medium · Microservices, Security, Senior

Difference between OAuth2 and OpenID Connect.

Medium · Microservices, Security, Senior

What is JWT and how is it used in authentication?

Medium · Microservices, Security, Senior

How do you handle role-based access control in microservices?

Medium · Microservices, Security, Senior

What is API security in microservices?

Medium · Microservices, Security, Senior

How do you secure secrets in microservices?

Medium · Microservices, Security, Senior

What is zero-trust security model?

Hard · Microservices, Security, Staff

Explain mutual TLS (mTLS) in service-to-service communication.

Hard · Microservices, Security, Staff

How do you protect microservices from DDoS attacks?

Hard · Microservices, Security, Staff

What is rate limiting and how does it help in security?

Easy · Microservices, Security, Fresher

How do you handle multi-tenancy security in microservices?

Hard · Microservices, Security, Staff

Explain token expiration and refresh in microservices authentication.

Medium · Microservices, Security, Senior

What are common vulnerabilities in microservices?

Medium · Microservices, Security, Senior

How do you implement API Gateway security policies?

Medium · Microservices, Security, Senior

What is CORS and how do you handle it in microservices?

Easy · Microservices, Security, Fresher

How do you handle encryption at rest and in transit?

Medium · Microservices, Security, Senior

Explain secrets rotation in microservices.

Medium · Microservices, Security, Senior

What is penetration testing for microservices?

Hard · Microservices, Security, Staff

How do you secure microservices running on Kubernetes?

Hard · Microservices, Security, Staff

What is CI/CD in microservices?

Easy · Microservices, CI/CD & DevOps, Fresher

How do you design a CI/CD pipeline for microservices?

Medium · Microservices, CI/CD & DevOps, Senior

What are the challenges of CI/CD in microservices?

Medium · Microservices, CI/CD & DevOps, Senior

Explain blue-green deployment strategy.

Medium · Microservices, CI/CD & DevOps, Senior

Explain canary release strategy.

Medium · Microservices, CI/CD & DevOps, Senior

How do you implement feature toggles in microservices?

Medium · Microservices, CI/CD & DevOps, Senior

What is progressive delivery?

Medium · Microservices, CI/CD & DevOps, Senior

How do you handle rollback in microservices deployment?

Medium · Microservices, CI/CD & DevOps, Senior

Explain GitOps for microservices deployment.

Medium · Microservices, CI/CD & DevOps, Senior

What is infrastructure as code (IaC)?

Easy · Microservices, CI/CD & DevOps, Fresher

How do you use Terraform/CloudFormation for microservices?

Medium · Microservices, CI/CD & DevOps, Senior

What is Helm and its role in Kubernetes deployments?

Medium · Microservices, CI/CD & DevOps, Senior

How do you manage secrets in CI/CD pipeline?

Medium · Microservices, CI/CD & DevOps, Senior

Explain automated testing in microservices CI/CD.

Medium · Microservices, CI/CD & DevOps, Senior

What is chaos testing in CI/CD pipeline?

Hard · Microservices, CI/CD & DevOps, Staff

How do you handle multi-service deployments?

Hard · Microservices, CI/CD & DevOps, Staff

What is container registry and how is it used?

Easy · Microservices, CI/CD & DevOps, Fresher

Explain continuous monitoring in DevOps pipeline.

Medium · Microservices, CI/CD & DevOps, Senior

What is service versioning in CI/CD?

Medium · Microservices, CI/CD & DevOps, Senior

How do you handle database migrations in microservices CI/CD?

Hard · Microservices, CI/CD & DevOps, Staff

How do you design an e-commerce platform with microservices?

Hard · Microservices, System Design, Architect

Design a payment service with fault tolerance.

Hard · Microservices, System Design, Staff

How do you design a notification service using microservices?

Hard · Microservices, System Design, Staff

Explain the design of an order management system.

Hard · Microservices, System Design, Staff

How do you design a logging and monitoring service?

Hard · Microservices, System Design, Staff

Design a microservices architecture for a video streaming platform.

Hard · Microservices, System Design, Staff

How do you handle data consistency in financial transactions?

Hard · Microservices, System Design, Architect

Design a search service with scalability in mind.

Hard · Microservices, System Design, Staff

How do you integrate legacy systems with microservices?

Hard · Microservices, System Design, Architect

How do you design for GDPR compliance in microservices?

Hard · Microservices, System Design, Architect

Explain design considerations for real-time chat service.

Hard · Microservices, System Design, Staff

How do you build an API Gateway for multiple services?

Hard · Microservices, System Design, Staff

Design a recommendation engine with microservices.

Hard · Microservices, System Design, Staff

How do you design a fault-tolerant authentication service?

Hard · Microservices, System Design, Staff

Explain architecture for microservices in a healthcare system.

Hard · Microservices, System Design, Architect

How do you handle schema evolution in real-world microservices?

Hard · Microservices, System Design, Staff

Design a scalable IoT platform with microservices.

Hard · Microservices, System Design, Architect

How do you ensure observability in a production-grade system?

Hard · Microservices, System Design, Architect

How do you design for multitenancy in SaaS microservices?

Hard · Microservices, System Design, Architect

What are trade-offs between synchronous and asynchronous designs in real-world systems?

Hard · Microservices, System Design, Staff

What happens when a service in a saga fails?

Hard · Microservices, Tricky & Advanced, Staff

How do you debug issues in distributed transactions?

Hard · Microservices, Tricky & Advanced, Staff

Explain idempotency challenges in microservices.

Hard · Microservices, Tricky & Advanced, Staff

How do you detect and prevent cascading failures?

Hard · Microservices, Tricky & Advanced, Staff

What is distributed tracing overhead?

Hard · Microservices, Tricky & Advanced, Staff

How do you handle schema mismatch between services?

Hard · Microservices, Tricky & Advanced, Staff

Explain eventual consistency pitfalls in real-world systems.

Hard · Microservices, Tricky & Advanced, Staff

What is head-of-line blocking in message queues?

Hard · Microservices, Tricky & Advanced, Staff

How do you detect memory leaks in microservices?

Hard · Microservices, Tricky & Advanced, Staff

What is the impact of chatty APIs on performance?

Medium · Microservices, Tricky & Advanced, Senior

How do you prevent over-fetching and under-fetching in APIs?

Medium · Microservices, Tricky & Advanced, Senior

What are pitfalls of using shared libraries across microservices?

Medium · Microservices, Tricky & Advanced, Senior

How do you prevent dependency hell in microservices?

Medium · Microservices, Tricky & Advanced, Senior

Explain the impact of network latency in microservices.

Medium · Microservices, Tricky & Advanced, Senior

What are clock-skew issues in distributed systems?

Hard · Microservices, Tricky & Advanced, Staff

How do you test microservices locally with dependencies?

Medium · Microservices, Tricky & Advanced, Senior

Explain shadow traffic testing in microservices.

Hard · Microservices, Tricky & Advanced, Staff

What are sidecar patterns and their benefits?

Hard · Microservices, Tricky & Advanced, Staff

How do you migrate from monolith to microservices?

Hard · Microservices, Tricky & Advanced, Architect

What are best practices for API documentation in microservices?

Easy · Microservices, Tricky & Advanced, Fresher

When should you NOT use microservices?

Easy · Microservices, Core Concepts, Fresher

Explain HTTP methods, status codes, and REST basics for microservice APIs.

Easy · Microservices, Core Concepts, Fresher

How do you manage environment-specific configuration in microservices?

Easy · Microservices, Core Concepts, Fresher

Explain basic networking concepts for microservices (DNS, ports, load balancers).

Easy · Microservices, Core Concepts, Fresher

Difference between stateless and stateful microservices.

Easy · Microservices, Core Concepts, Senior

What makes a good REST API contract between microservices?

Easy · Microservices, Service Communication, Fresher

What are message queues and when do you use them in microservices?

Easy · Microservices, Service Communication, Fresher

What is connection pooling and why does it matter in microservices?

Medium · Microservices, Service Communication, Senior

What is the Backend-for-Frontend (BFF) pattern?

Medium · Microservices, Service Communication, Senior

What is GraphQL federation in a microservices architecture?

Hard · Microservices, Service Communication, Staff

What is backpressure and how do you handle it in microservices?

Hard · Microservices, Resilience, Staff

Explain PACELC theorem and its relevance to microservices.

Hard · Microservices, Resilience, Staff

What is the read-your-writes consistency problem?

Medium · Microservices, Data Management, Senior

What is the Anti-Corruption Layer (ACL) pattern in microservices migration?

Hard · Microservices, Data Management, Staff

Difference between liveness and readiness probes.

Medium · Microservices, Observability, Fresher

How do you run multiple microservices locally with Docker Compose?

Medium · Microservices, CI/CD & DevOps, Fresher

Explain the testing pyramid for microservices.

Medium · Microservices, CI/CD & DevOps, Senior

Design a URL shortener using 2–3 microservices.

Medium · Microservices, System Design, Fresher

How do you handle poison messages in message-driven microservices?

Hard · Microservices, Tricky & Advanced, Senior

What is Conway's Law and how does it affect microservice boundaries?

Medium · Microservices, Architecture & Organization, Staff

Explain team topologies for microservices organizations.

Medium · Microservices, Architecture & Organization, Staff

What is platform engineering and how does it support microservices teams?

Hard · Microservices, Architecture & Organization, Staff

What are error budgets and how do they drive reliability decisions?

Medium · Microservices, Architecture & Organization, Staff

How do you lead incident response across multiple microservice teams?

Hard · Microservices, Architecture & Organization, Staff

What is a service catalog and why is it important at scale?

Medium · Microservices, Architecture & Organization, Staff

How do you perform zero-downtime data migration with dual writes and shadow reads?

Hard · Microservices, Architecture & Organization, Staff

How do you govern event schemas across dozens of microservices?

Hard · Microservices, Architecture & Organization, Staff

What is a distributed monolith and how do you detect/prevent it?

Medium · Microservices, Architecture & Organization, Staff

What are Architecture Decision Records (ADRs) and how do you use them?

Easy · Microservices, Architecture & Organization, Architect

How do you decide build vs buy vs integrate for microservice capabilities?

Medium · Microservices, Architecture & Organization, Architect

What is a data mesh and how does it relate to microservices?

Hard · Microservices, Architecture & Organization, Architect

How do you design microservices for multi-cloud or hybrid cloud?

Hard · Microservices, Architecture & Organization, Architect

Explain context maps in Domain-Driven Design for microservices.

Hard · Microservices, Architecture & Organization, Architect

What are architectural fitness functions?

Hard · Microservices, Architecture & Organization, Architect

How do you manage service lifecycle, deprecation, and sunset at scale?

Medium · Microservices, Architecture & Organization, Architect

How do you optimize microservices cost (FinOps) at architecture level?

Medium · Microservices, Architecture & Organization, Architect

Explain enterprise integration patterns (ESB vs event bus vs point-to-point).

Hard · Microservices, Architecture & Organization, Architect

What is evolutionary architecture for microservices?

Hard · Microservices, Architecture & Organization, Architect

How do you plan a 5-year migration from monolith to microservices?

Hard · Microservices, Architecture & Organization, Architect