Tuesday 5 March 2024
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Commonly Asked Web API Interview Questions

Commonly Asked Web API Interview Questions

The knowledge of web API is crucial for numerous jobs. Companies expect you to have a sound understanding of web API before joining them. However, you cannot become proficient in web API concepts and confidently answer your recruiters without practicing the frequently asked questions.

Yes, you’ve read it correctly! You cannot ace the interviews dealing with web API understanding without knowing the likely-asked questions. Over the years, multiple recruiters frame some common web API questions to measure the proficiency of applicants in an interview.

So, we are here to help you and increase your success chances tremendously. Below is a comprehensive collection of web API questions that your panelists might ask in your upcoming interview. These questions will help you test your preparation and identify your weaknesses quickly.

Regular practice, performance analysis, and successive improvement will make you ready for all types of web API-related queries asked to you in an interview.

So, are you ready to understand the latest web API interview questions?

Let’s dive in!

  • What’s the need to have a Web API?

A web API is a service or doorway offering vital datasets from the server. Here are the reasons making Web API so crucial:

  • It provides a data access interface for websites and client applications.
  • We can also use it to withdraw data from a database and store the used dataset into it.
  • It remains compatible with numerous text formats, including XML, JSON, and others.
  • It works with any browser and device, including mobile, web, desktop, etc.
  • It makes use of low-bandwidth data, like XML or JSON. So, it’s suitable for devices with limited bandwidth, such as smartphones.
  • Web API is more relevant for UI/UX, raises interest in the company’s goods and services, and enhances website traffic from a business standpoint.
  • Which return types does Web API support?

Web API has no well-defined return data type. It can return any of them based on business needs. Many renowned HTTP commands like GET, PUT, and POST can return data in various forms, depending on the use case.

  • Can you differentiate between Web API and WCF?

WCF (Windows Communication Foundation): It is a SOAP development framework (Service-oriented applications). This framework is used to create, configure, and deploy network-distributed services and strategically implement them.

Web API: A web API is an application programming interface that web browsers and web servers may utilize. Browser API adds to the capabilities of web browsers, whereas Server API adds to the functionality of web servers.

  • Describe the benefits of using Rest in Web API?

REST is crucial and highly advantageous in Web API due to the following reasons:

  • It offers minimal data transfer between server and client.
  • It is lightweight, convenient, and easy to use.
  • It brings more flexibility to the table.
  • It manages and controls several call types, returning numerous data formats.
  • It is a best-fit choice for mobile applications as it offers minimal data transfer between server and client.
  • It leverages simple HTTP calls for inter-machine communication and does not use complex alternatives like COM+, CORBA, RPC, or SOAP.
  • What do you mean by Web API 2.0?

We can define Web API 2.0 as an improved and enhanced Web API functionality. The latest version remains compatible with numerous latest features like the following:

  • New Attribute for Routing
  • OAuth 2.0-secured ASP.NET Web API
  • Compatibility with
  • Cross-Origin requests using CORS
  • IHttpActionResult return type
  • Compatibility with $expand, $select in OData Service
  • Which protocol is compatible with Web API?

Web API remains compatible with HTTP protocol only.

  • Name the open-source libraries that WEB API for JSON serialization use?

Generally, we leverage the Json.NET library in Web API for JSON serialization.

  • What do you mean by XML and JSON?

XML (Extensible Markup Language):

  • It is built to hold and transfer data.
  • It shares similarities with HTML except for being more flexible than HTML. It happens because XML lets users build custom tags.
  • It can be implemented to convey structured information like data, configuration, documents, etc.

JSON (JavaScript Object Notation):

  • JSON is a lightweight format built to hold and transfer data.
  • It is a standard text-based and convenient to understand format. JSON is used to represent structured information according to JavaScript object syntax.
  • It is a rapid and easier-to-use format.
  • Who are the Web API consumers?

Web API is included or consumed by several clients, including browsers, mobile devices, Apple devices, etc. We can also use it with native applications requiring web services but not SOAP. Any client that implements HTTP commands such as GET, PUT, POST, and DELETE can use it.

  • Mention the ways to handle errors in Web API?

Generally, web APIs offer more flexibility regarding managing problems. Exception handling is a programming approach for dealing with run-time faults in application code. We can utilize HttpError, HttpResponseException, register exception filters, Exception filters, and Exception handlers to deal with errors. We can identify unhandled exceptions on actions or controllers with an exception filter. Also, we can use exception handlers to identify any form of unhandled exception application-wide, and HttpResponseException can be utilized when an exception is possible.

  • What exactly is ASP.NET Web API?

Active server pages (ASP) means Active Server Pages. ASP.NET is an advanced and enhanced version of the original ASP. It’s a programming framework for developing HTTP services that respond to client requests. We can access it through various programs on a variety of platforms. It is a Microsoft open-source technology that allows you to construct and consume HTTP-based services on top of the.NET framework. ASP.NET Web API makes creating HTTP services a breeze. These services are available to several clients, as listed below:

  • Desktop Applications
  • IoT
  • Mobile Applications
  • Browsers
  • Name the new features in ASP.NET Web API 2.0

ASP.NET Web API has several unique and exciting features as given below:

  • Attribute Routing
  • Web API OData
  • OWIN (Open Web Interface for .NET) self-hosting
  • IHttpActionResult
  • CORS (Cross-Origin Resource Sharing)


You are prepared for the interview now! Revise your concepts before the D-day using these web API questions and secure your selection in the company. All the best!