Rest API Interview Questions

Rest API Interview Questions

REST API is widely considered one of the best standard protocols for Internet APIs. REST API represents at least 69% of the share of all the APIs on the Internet. The Full name of API is Application Program Interface that is secure but also complicated to develop and hard to manage. That’s why a society of researchers appeared along with the purpose of REST (REpresentational State Transfer) in 2000. REST is designed to improve the power of APIs by creating a developed communication channel between two servers that are physically distant from each other. Now, if you are in an interview where you have to answer questions related to cloud computing and relevance, then you need to know what are the most common API interview questions you would be asked. In this post, we are going to provide you with the Top REST API Questions and Answers to help you prepare for an interview.

Basic REST API Interview Questions

If you are at the beginner level in REST API, then these are questions and answers to begin your journey with:

1. What Do You Think are RESTful Web Services?

RESTful Web Services refer to the services that consist of the REST design. This platform uses the HTTP protocol method to create web services. The HTTP method provides scalability and helps in building different applications using different programming languages, etc. RESTful web services allow developers to access multiple types of resources that the client requires. The RESTful service implementation will send the request to the server from the web browser. The most important components of the RESTful service implementation include source codes, response and request body, request headers, and resources.

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2. What Protocol Do RESTful Web Services Use?

RESTful web services use the most popular HTTP protocol that helps client applications communicate with the server. HTTP also helps the developers to access resources in the web services architecture of Restful.

3. What is a REST Resource?

Every component and content in the web services architecture is a resource in REST. The resource is similar to the target in the object-oriented programming environment. The materials include text files, images, dynamic data, HTML pages, or anything important. The REST server allows you to access this data and the REST client lets you modify the data. Every resource in the environment is globally recognized as a Uniform Resource Identifier.

4. What is a Uniform Resource Identifier (URI)?

URI is just an abbreviation of Uniform Resource Identifier that developers use to identify the resources in the REST environment. The format of URI is this:


There are two types of URI; one is Uniform Resource Name (URN) and Uniform Resource Locator (URL). URN checks the name of the resource to identify it by its uniqueness. However, URN does not mention where you can find the resource, but the URN is used as a template that other parsers can use to determine the resource. URL can fetch the resource from its specific location.

5. Mention the Features of the RESTful Web Services?

Every RESTful web services need to have the following features:

  • Client-Server representation
  • HTTP protocol
  • Proper communication between the server and the client through messaging
  • Identifying the resources in the architecture through URIs
  • The statelessness concept that does not depend on the request and response of the client onto others. Thus, it provides the required data whenever requested.
  • Caching concept that reduces the server calls of returned types of calls
  • The web settings can handle SOAP services in terms of implementation protocol to the REST environment design.

6. What is Statelessness in RESTful Web Services?

The architecture of REST is created in a way that the server does not have to maintain the client state. Not required to maintain the client state is known as statelessness. The client provides this context to the server using the client request provided by the server.

Advanced REST API Questions

Now if you are in the intermediate or advanced level in the REST API exam, then you need answers to more difficult questions than the basic REST API questions. Here are some of them.

7. While You are Creating URIs for Web Services, What Practices Do You Need to Follow?

Here are the best practices that you want to consider during designing the URI of the REST web services:

  • Use plural nouns to identify resources, such as “users”.
  • Use underscore or hyphen while applying long names of resources. Don’t use spaces between words.
  • Only use lowercase letters while writing URIs because they are case-sensitive.
  • While you are creating a URI, you need to maintain backward compatibility. When you update the URI, you need to redirect the older one to the original one using the HTTP status code 300.

8. What are the Core Components of HTTP Requests?

In REST, the HTTP requests have the following five main components:

  • Method/Verb that represents the methods of requests and it includes GET, PUT, POST, DELETE, etc.
  • URI can identify the resources in the server.
  • The HTTP version will identify the version of HTTP protocol such as HTTP v1.1
  • Request Header includes request metadata like content type, supported format, cache settings, etc.
  • Request body represents the message that will be fetched to the server.

9. What are the Core Components of HTTP Responses?

HTTP responses have four main components:

  • Response Status Code. For example, 400 represents the client-side error, and 200 represents a successful response
  • HTTP Version represents the HTTP protocol version
  • Response Header represents the metadata data in the response message that includes content type, content format, etc.
  • Response Body represents the actual resource or message that the server has returned

10. What is the Messaging Technique in RESTful Web Services?

Messaging is the main mode of exchanging data for signaling within the client and server. HTTP plays the role of communicating with clients and servers by conveying messages through requests and responses. The HTTP request will be sent to the client that has information about the data, and the server will submit the responses.


There are many important HTTP methods in web services. They are GET, PUT, POST, DELETE, and OPTIONS. GET fetches the names of users on the server, and PUT creates a new resource on the server. POST is used for updating a precious resource, but you can also create a new one with this. With DELETE, you can delete any resource on their server. With OPTIONS, you can fetch any supported options of the resources that are ready in your server. Now, if PUT and POST are so similar, what is the difference? The only major difference between these two is that the results you get from PUT will always be the same no matter how many times you update the previous resource. But the result you get from POST will always be new every time you update the resource.

Overall, these questions and answers are the most common ones asked in a REST API interview. If you want to learn more questions and answers about the same, then check out our other articles where we have clarified more difficult and important REST API questions.


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