REST API between services in Microservices - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the main advantage of using REST APIs between microservices?

Consider a system where multiple microservices communicate using REST APIs. What is the primary benefit of this approach?

A It enforces a strict contract and allows services to evolve independently.

B It requires all services to be written in the same programming language.

C It eliminates the need for any authentication or security measures.

D It guarantees zero network latency between services.

💡 Hint

Think about how REST APIs help services stay loosely connected.

REST APIs define clear contracts through endpoints and data formats, allowing each service to change internally without affecting others, promoting independent evolution.

❓ Architecture

intermediate

Which component is essential to manage REST API calls between microservices for load balancing?

In a microservices architecture using REST APIs, which component helps distribute incoming requests evenly across service instances?

A Message Queue

B Database Proxy

C API Gateway

D Load Balancer

💡 Hint

Think about what balances traffic among multiple servers.

A Load Balancer distributes incoming REST API requests across multiple instances of a service to ensure no single instance is overwhelmed.

❓ scaling

advanced

What is the best approach to handle high traffic REST API calls between microservices to avoid bottlenecks?

You notice that a microservice is overwhelmed by REST API calls from other services during peak times. Which approach best helps to scale and avoid bottlenecks?

A Disable caching to ensure fresh data on every request.

B Increase the timeout value for REST API calls to wait longer for responses.

C Implement asynchronous communication using message queues instead of direct REST calls.

D Reduce the number of service instances to limit traffic.

💡 Hint

Think about decoupling services to handle load better.

Using asynchronous messaging reduces direct REST API call load, allowing services to process requests at their own pace and improving scalability.

❓ tradeoff

advanced

What is a tradeoff when using REST APIs synchronously between microservices?

Using synchronous REST API calls between microservices has benefits and drawbacks. Which option correctly describes a tradeoff?

A Synchronous calls simplify error handling but increase latency and reduce fault tolerance.

B Synchronous calls eliminate network overhead but require complex message brokers.

C Synchronous calls guarantee zero data loss but prevent service scaling.

D Synchronous calls allow services to run offline without connectivity.

💡 Hint

Consider how waiting for responses affects system behavior.

Synchronous REST calls make it easier to handle errors immediately but can cause delays and cascading failures if a service is slow or down.

❓ estimation

expert

Estimate the number of REST API requests per second a microservice cluster can handle given these parameters

A microservice cluster has 5 instances. Each instance can handle 200 REST API requests per second. The load balancer distributes requests evenly. What is the total maximum requests per second the cluster can handle?

A 200 requests per second

B 1000 requests per second

C 400 requests per second

D 2500 requests per second

💡 Hint

Multiply the number of instances by the capacity per instance.

5 instances × 200 requests/second each = 1000 requests/second total capacity.