Interview Q&A

Short answer: (e.g., a user's data). The client receives an access token.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Example: GET /api/v1/orders/{id} vs. GET /api/v2/orders/{id} GET /api/v1/orders/{id} vs. GET /api/v2/orders/{id}

Example code

GET /api/v1/orders/{id} vs. GET /api/v2/orders/{id} GET /api/v1/orders/{id} vs. GET /api/v2/orders/{id}

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Consul, Eureka) to find available instances of the service it needs to communicate with. Once the client knows the available instances, it directly calls the service. Example: The Order Service queries Eureka to get the available instances of the Payment Service.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: deployments, helping you control how requests are routed between services.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: change occurs, such as creating a new order or processing a payment. The event is typically sent to a message broker like Kafka or RabbitMQ.

Real-world example (ShopNest)

After payment succeeds, ShopNest publishes OrderPaid. Inventory and Notification services react independently—no giant distributed transaction.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: business capabilities that can be made into separate services.

Real-world example (ShopNest)

After payment succeeds, ShopNest publishes OrderPaid. Inventory and Notification services react independently—no giant distributed transaction.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Microservices are an architectural approach where an application is divided into small, independently deployable services, each focused on a specific business function.

Explain a bit more

These services communicate with each other over APIs and are developed, deployed, and scaled independently. Monolithic architectures, in contrast, bundle all components of an application into a single, tightly coupled unit. Changes or scaling require the entire application to be redeployed. Key Differences: Microservices offer modularity, scalability, and independent deployment, while monolithic is a single, tightly integrated system that can be harder to scale and maintain as it grows.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Implement JWT (JSON Web Tokens) or OAuth 2.0 to ensure that only authenticated services can communicate with each other.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: And extract user roles for authorization. Example: Verify the signature of the JWT and check its expiry before forwarding the request to the microservices.

Real-world example (ShopNest)

ShopNest’s API Gateway routes /orders to the Order service and /payments to Payment—clients talk to one entry point.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: single response to the client, improving client experience. Example: An order summary could include data from the order service, inventory service, and shipping service.

Real-world example (ShopNest)

ShopNest’s API Gateway routes /orders to the Order service and /payments to Payment—clients talk to one entry point.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: And monitor traffic, failures, and performance.

Real-world example (ShopNest)

ShopNest’s API Gateway routes /orders to the Order service and /payments to Payment—clients talk to one entry point.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: pplication/vnd.example.v1+json.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: uthenticated services can communicate with each other.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: And load balancing across multiple service instances.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: And to handle compensation if a service fails.

Real-world example (ShopNest)

After payment succeeds, ShopNest publishes OrderPaid. Inventory and Notification services react independently—no giant distributed transaction.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: vailability and load balancing for databases.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Applications or services that require more powerful hardware but is less optimal for microservices due to their distributed nature.

Explain a bit more

Example: Increasing the memory or CPU for a service like the Payment Service that requires more processing power. Best practice: For microservices, horizontal scaling is preferred because it increases resilience and fault tolerance by distributing traffic and workloads across multiple instances.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: And roll out updates to the Payment Service without downtime.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: And manage internal communication. Scaling and Autoscaling: Use Kubernetes to automatically scale services based on traffic, ensuring that resources are efficiently utilized. Example: After containerizing a User Service using Docker, you would deploy it to a Kubernetes cluster using a Deployment and expose it with a Service for communication with other…

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1

Example code

GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1 Example: GET /api/orders?id=123&version=1

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: ppropriate service instance. Tools like Kubernetes provide built-in service discovery by assigning DNS names to services, and Kubernetes automatically routes traffic to vailable service instances. Example: In Kubernetes, a Payment Service might be exposed by a Service resource, and requests to this service are routed to healthy pods based on their labels.

Real-world example (ShopNest)

ShopNest’s API Gateway routes /orders to the Order service and /payments to Payment—clients talk to one entry point.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: and update inventory quantities.

Real-world example (ShopNest)

After payment succeeds, ShopNest publishes OrderPaid. Inventory and Notification services react independently—no giant distributed transaction.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Benefits: Scalability: Microservices allow for independent scaling of services based on demand.

Explain a bit more

Faster Development: Small, focused teams can develop and deploy services independently. Resilience: A failure in one service doesn’t affect the whole system. Technology Agnostic: Different services can be built using different technologies. Challenges: Complexity: Managing many services and their interactions can be difficult. Data Management: Ensuring data consistency across services can be challenging. Latency: Inter-service communication over a network can introduce latency. Deployment Overhead: Managing multiple deployments requires a sophisticated CI/CD pipeline.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: service-to-service communication across multiple regions, providing consistent service discovery, load balancing, and security policies.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: my-service.my-namespace.svc.cluster.local) to the appropriate pod IPs.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.