Answers to 7 Web API Interview Questions
If you apply for a job as a web developer, you may be asked about Web API (Application Programming Interface). Understanding the types of questions you’ll be asked and pre-planning your responses will make you appear more confident and competent during the interview. In this article, we share seven frequent Web API interview questions and sample solutions to help you prepare for your next interview.
Seven Web API interview questions and answers
Here are some examples of commonly asked Web API interview questions:
- What is a Web API, exactly?
- What are the benefits of using Web API?
- What is the difference between Web API and WCF?
- Is Web API the replacement for WCF?
- What are the main differences between Web API and MVC?
- What is REST, exactly?
- Can you name six constraints of the REST architectural pattern?
1. What is a Web API, exactly?
When answering this question, demonstrate that you understand the goal of Web API and, if applicable, how much experience you have with Web API.
Example: “A Web API (Application Programming Interface) is a framework that enables the creation of HTTP services that can be accessed by a wide range of clients, including browsers and mobile devices. The ASP.NET Web API can be used to build these services on the.NET framework.”
2. What are the advantages of utilizing Web API?
Because other technologies are comparable to Web API, your response to this question should demonstrate that you understand what sets Web API apart.
“There are numerous reasons you might want to use Web API, including the ability to create non-SOAP-based HTTP services; its use of familiar HTTP verbs for Create, Read, Update, and Delete operations; its lightweight architecture, which makes it ideal for low-bandwidth devices such as smartphones; and its ability to select response output in either JSON or XML, as well as support for the Open Data (OData) protocol.”
3. What is the difference between Web API and WCF?
Demonstrate your understanding of WCF and how it differs from Web API. While the interview may be centered on Web API, knowledge of other related technologies is advantageous.
Example: “WCF (Windows Communication Foundation) is a service-oriented application development framework that supports a number of transport protocols (e.g., HTTP, TCP, MSMQ). Clients of WCF must be able to read and write XML. Because Web API is designed for HTTP services, it has a low bandwidth. It supports non-SOAP services as well as the vast bulk of MVC functionality.”
4. Is Web API intended to be a replacement for WCF?
Some people are skeptical about WCF’s continued importance as Web APIs become increasingly common. In your response, demonstrate that you grasp the benefits of each. The example response highlights WCF’s continuous significance. Prepare to explain why you disagree with this stance.
Example: “No, since, while Web API is lightweight because it only uses HTTP, it lacks the power and flexibility of WCF. If you simply need to use HTTP as your transport, the Web API is unquestionably the better solution. If you need to use a different protocol (for example, TCP or Named Pipes), you must use WCF.”
5. What are the main differences between Web API and MVC?
MVC is a web application development model that includes a front-end, controls, and back-end functions. Web API allows you to build HTTP services that can communicate with a variety of clients. In your response, demonstrate that you understand MVC and how it differs from Web ASP.
Example: “One of the differences between Web API and MVC is that MVC (Model View Controller) is used to build web apps with user interfaces. Web API is used to create HTTP services. In the MVC design pattern, the web application returns both a view and data. In contrast, a web API just returns data. Web API converts all inquiries into actions using HTTP verbs. MVC connects requests to action methods. MVC only supports JSON data, but Web API supports JSON, XML, and more forms.”
6. Exactly what is REST?
REST is a specific architectural style. There may or may not be a REST-compliant Web API. It is improper to use the words Web API and REST interchangeably. Your answer to this question should show that you understand REST and how it differs from Web API.
Example: “REST (Representational State Transfer) is an architectural approach that uses a set of standards to simplify system communication over the internet using HTTP. RESTful systems are stateless in the sense that clients and servers are unaware of one another’s current state. They are also modular, so clients and servers, user interfaces, and data storage can all be maintained independently. A Web API may or may not be RESTful.”
7. Can you name the six restrictions of the REST architectural pattern?
Only five of the REST limitations are mandatory; the sixth is optional. Make a note of it when you respond if the interviewer asks the question in this manner. Because Web APIs can be RESTful, you must grasp the REST constraints.
Example: “A Web API must meet five standards and, potentially, a sixth to be considered RESTful (that is, REST-compliant).
- Client-server independence: Clients and servers are not interdependent. Clients only need to know the server resource’s URI (Uniform Resource Identifier).
- Stateless: The server request from the client should be self-contained. The server does not need to maintain any information about the client in order to perform the request.
- Each resource made available to clients must have a single logical URI and a means to obtain further data. A consistent approach for accessing and modifying resources is required.
- Cacheable: The client should be able to save specific server responses for performance and scalability (e.g., lists of items that do not change frequently).
- APIs, data storage, and request authentication are distributed over three independent servers in a tiered architecture. The client is usually unaware whether it is connected directly to the target server or to one of the intermediary servers.
- The constraint of code-on-demand is optional. If necessary, the server can supply executable code instead of static XML or JSON representations of resources.”
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