API gateway concept in HLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an API Gateway?

An API Gateway is a server that acts as a single entry point for all client requests to multiple backend services. It handles request routing, composition, and protocol translation.

beginner

Name two main functions of an API Gateway.

1. Routing client requests to the correct backend service.<br>2. Handling security like authentication and rate limiting.

intermediate

Why use an API Gateway instead of direct client calls to services?

It simplifies client communication by providing one endpoint, improves security by centralizing checks, and can optimize performance by aggregating responses.

intermediate

What is request composition in the context of an API Gateway?

Request composition means the API Gateway combines data from multiple backend services into a single response for the client.

intermediate

How does an API Gateway help with scalability?

By offloading tasks like authentication, rate limiting, and request routing, it reduces load on backend services and allows independent scaling of components.

What role does an API Gateway play in a microservices architecture?

A Stores all data for backend services

B Acts as a single entry point for client requests

C Replaces the database layer

D Runs client-side code

An API Gateway acts as a single entry point, routing requests to appropriate backend services.

Which of the following is NOT a typical feature of an API Gateway?

A Rate limiting

B Authentication and authorization

C Request routing

D Direct database queries

API Gateways do not perform direct database queries; they route requests to backend services that handle data.

How does an API Gateway improve security?

A By centralizing authentication and authorization

B By storing user passwords

C By encrypting backend databases

D By running client code securely

API Gateways centralize security checks like authentication and authorization before forwarding requests.

What is request composition in an API Gateway?

A Combining multiple backend responses into one

B Encrypting client requests

C Caching database queries

D Running backend services

Request composition means the API Gateway merges data from multiple services into a single response.

Which benefit does an API Gateway provide for scalability?

A Stores all client data

B Runs all backend services itself

C Offloads common tasks from backend services

D Eliminates the need for load balancers

By handling tasks like authentication and routing, the API Gateway reduces backend load, aiding scalability.

Explain the role and benefits of an API Gateway in a microservices system.

Think about how it simplifies client communication and protects backend services.

Describe how an API Gateway manages client requests and backend responses.

Consider the flow from client to backend and back.