Vibha Sengar — Published On October 9, 2022 and Last Modified On November 4th, 2022
Beginner Interview Questions

This article was published as a part of the Data Science Blogathon.


Web API is a vital application programming interface that enables web services across various browsers and devices, including tablets, mobile phones, etc. Its lightweight and streamlined services and its usability as a stand-alone web service application are of great importance.

web api
Source: Medium

Suppose you are a Web API student or a professional building your skills in this framework. In that case, you are well aware of the importance of accessing a dependable repository of interview questions. Due to its practical nature, every collection of questions must address its implementation in real-world circumstances. These interview questions might also assist you in preparing for your ideal career in this industry.

Let’s gain a deeper grasp of the concept by examining these Web API Interview Questions, which will aid you during a job interview or just improve your general knowledge and understanding of this topic.

Interview Questions

Q1. Why is Web API so important?

Web API is typically regarded as a service that gives us data or information from the server. It is very important for the following reasons:

  • It provides a data access interface for websites and client applications.
  • It may be used to retrieve data from and save data to the database.
  • It supports several text formats, including XML, JSON, etc.
  • It is appropriate or compatible with every browser and every device, including mobile, desktop, online, etc.
  • It uses low-bandwidth data formats, like XML or JSON, and is, therefore suitable for devices with limited bandwidth, like smartphones.

Web API is more relevant for UI/UX from a commercial perspective, stimulates interest in the company’s products and services, and boosts website traffic.

Q2. What differences exist between Web API and WCF REST API?

A: Web API is appropriate for HTTP-based services, but WCF REST API is optimal for Message Queues, one-way messaging, and duplex connectivity. WEB API accepts every media format, including XML and JSON, while WCF supports SOAP and XML. WCF is great for establishing service-oriented applications, while ASP.Net Web API is ideal for providing HTTP services. It requires no configuration to operate, but WCF requires a notable amount of configuration.

Q3. What are the different Web API return types?

An action of a controller can return the following values:

  • Void – It will display empty
  • HttpResponseMessage – This function converts the response into an HTTP message.
  • IHttpActionResult – invokes ExecuteAsync internally to generate a HttpResponseMessage.
  • Other types – The serialized return value can be written into the response body.

Q4. What are the different HTTP Methods?

There are a variety of HTTP methods that may be used depending on the situation. These techniques are case-sensitive and need capitalization.

  • GET – The GET method retrieves or gets information from a server using a specified URI.
  • HEAD — This is identical to the GET method but only transports the status line and header section.
  • PUT- It is used for updating and replacing all existing resources with the submitted material.
  • POST – A POST request is used to transmit data to a server.
  • DELETE — Deletes all current resources specified by a URI.
  • OPTIONS – Describe the target resource’s communication options.
  • CONNECT – Establishes a tunnel to the specified server.
  • TRACE — Performs a message loop-back test along the path to the resource being targeted.

Among these processes, The most frequent methods are GET/PUT/POST/DELETE.

Q5. What is Web API version 2.0?

It’s mainly an improved and upgraded capability. This new version supports the following new features:

  • New Routing Properties
  • Securing the ASP.NET Web API with OAuth 2.0
  • CORS support for Cross-Origin requests
  • IHttpActionResult is the return type for HTTP actions.
  • $expand and $select support in OData Service

Web API 2.0 is regarded as an excellent choice and an acceptable development model due to its new capabilities, which make it easier to build RESTful service interfaces for clients running on diverse platforms. Additionally, routes can be configured at the Web API function or controller level.

Q6. What do you mean by SOAP?

SOAP is an XML messaging format used in interactions between online services. It lets the transmission of messages over HTTP or JMS, but additional transport protocols are supported too. It is a communications protocol also based on XML for exchanging data between computers.

Q7. When should ASP.NET Web API be selected over WCF?

It relies entirely on necessity. Choose ASP.NET Web API if you want solely HTTP-based services, as its lightweight architecture makes it suitable for devices with low bandwidth. WCF may be used to establish REST services too, but this involves extensive setup. WCF is the superior choice if you need a service that supports several transport protocols, like HTTP, UDP, TCP, etc.

Q.8 How do we deal with Web API errors?

Error and exception may be accomplished using the following classes:

  • Implementing HttpResponseException – This exception class contributes to returning the HTTP status code provided in the exception Constructor.
  • Implementing HttpError – This exception class facilitates the return of a relevant error code to the client as a HttpResponseMessage.
  • Implementing Exception filters – Exception filters aid in capturing unhandled exceptions or errors issued  may be used whenever a controller action call generates an unhandled exception.

Q9. Can you provide me with an example of Web API Routing?

name: "MyRoute,"//route name
routeTemplate: "api/{controller}/{action}/{id}",//as you can see "API" is at the beginning.
defaults: new { id = RouteParameter.Optional }

Q10. Describe XML and JSON.

XML (Extensible Markup Language):

  • It is intended specifically to store and convey data.
  • It is comparable to HTML but more flexible than HTML because users can create their own tags.
  • It is used to represent structured data like documents, data, and configuration.

JavaScript Object Notation (JSON):

  1. It is a
    lightweight data storage and transmission format.
  2. It is a
    standard text-based format used to express structured data based on
    JavaScript object syntax and is easy to comprehend.
  3. It is quicker and simpler to use.


Web API is extensively used in all web-based applications to send data effectively and securely. To be a great web developer, you must understand Web API’s fundamentals and sophisticated features, along with their most recent versions on the market, how they function, and more. Some key points from the article are:

  • Web API provides web services across browsers and devices, like tablets, smartphones, etc
  • It supports several text formats, including XML, JSON, etc.
  • Web API 2.0 makes it easy to establish RESTful service interfaces for clients on multiple platforms.
  • XML stands for Extensible Markup Language, and JSON stands for JavaScript Object Notation

We hope this blog article has helped you familiarize yourself with frequently requested web API interview questions. These commonly requested interview questions can help you hone your skills and ace your next interview.

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One thought on "Most Commonly Asked Web API Interview Questions"

Prince Quaye
Prince Quaye says: October 10, 2022 at 12:41 am
I've learnt a lot about the importance of Web API applications. Reply

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