Top 40+ Web API Interview Questions and Answers for 2023 - IQCode

Introduction to Web API

Web API has become an integral part of modern web development. It allows developers to create applications that can communicate with other software systems over the internet and exchange data. It was first introduced in the early days of e-commerce, and since then, several well-known companies have launched their APIs to help the developers community. The following are some key events in the history of Web API:

  • 7 Feb 2000: Salesforce introduced its API at IDG Demo 2000 conference.
  • 20 Nov 2000: eBay launched its eBay API along with the Developers Program.
  • 16 July 2002: Amazon launched web services that allow developers to implement the content and features of into their own websites.

Although web APIs were initially only recognized as a hobby by mainstream businesses, today, they have become a core part of the internet infrastructure.

Web API Basic Interview Questions

Here are some fundamental interview questions related to Web API:

  1. What is the importance of Web API?

Web API allows developers to create applications that can communicate with other software systems over the internet and exchange data efficiently. Using this technology, developers can integrate existing services into their own applications, create new applications, and improve the overall user experience.

What is a Web API and Why is it Used?

A Web API (Application Programming Interface) is a set of protocols and tools that allows third-party applications to interact with a web application. It provides a way to share data and functionality between different systems.

There are various reasons why Web APIs are used, including: - Enabling communication and data exchange between different platforms and applications - Integrating with third-party services and applications - Simplifying software development by providing a pre-built solution for commonly needed functionality - Allowing for remote access to data and services, which can improve scalability and performance - Providing a standard way to interface with a web application, making it easier for developers to work with.

Overall, Web APIs play a vital role in modern web application development and have become increasingly popular in recent years.

Main Return Types Supported in Web API

In Web API, the most commonly used return types are:

1. XML
3. Plain Text
4. JPG/PNG Images
5. Custom Types

These return types allow APIs to communicate data effectively and efficiently with client applications. Depending on the specific use case, one type may be preferable over another.

Web API vs. WCF: What's the Difference?

When it comes to developing web applications, two common technologies are Web API and WCF (Windows Communication Foundation). While both can be used to create web services, there are some key differences to consider.

Web API is a framework for building HTTP-based services that can be consumed by various clients, including web browsers and mobile devices. It is designed to be lightweight, simple to use, and optimized for the web. Web API is built on top of the ASP.NET framework and supports a variety of data formats, including XML and JSON.

On the other hand, WCF is a framework for building distributed systems that can communicate over multiple transports, including HTTP, TCP, and named pipes. It is designed to be more flexible and can handle more complex scenarios than Web API. WCF is built on top of the .NET Framework and supports a wide variety of protocols, including SOAP and REST.

The choice between Web API and WCF depends on your requirements. If you need a lightweight and simple service that can be consumed by a variety of clients, Web API is a good choice. However, if you need a framework that can handle more complex scenarios and support a wide variety of protocols, WCF might be the better option.

// Example of a simple Web API controller method that returns a list of products
public class ProductsController : ApiController
    public List<Product> GetProducts()
        // Retrieve products from a data source
        List<Product> products = new List<Product>();
        // TODO: Add logic to retrieve products
        return products;

// Example of a WCF service contract that defines an operation to retrieve a list of products
public interface IProductService
    List<Product> GetProducts();

public class ProductService : IProductService
    public List<Product> GetProducts()
        // Retrieve products from a data source
        List<Product> products = new List<Product>();
        // TODO: Add logic to retrieve products
        return products;

Reasons to Choose Web API over WCF

Web API provides a more modern and flexible way of building HTTP services compared to WCF. Here are some of the reasons why you might want to choose Web API over WCF:

  • Easy to learn and use: Web API is built on top of the ASP.NET platform, which makes it easier to learn and use if you are already familiar with ASP.NET.
  • Lightweight: Web API is designed to be lightweight and fast, making it ideal for building RESTful services that don't require the full power of WCF.
  • Support for multiple platforms and devices: Web API is designed to work with a wide range of platforms and devices, including desktop and mobile browsers, as well as native mobile apps.
  • JSON and XML support: Web API supports both JSON and XML data formats, making it easier to work with a wider range of clients and services.
  • Easy integration with other frameworks and libraries: Web API is designed to work seamlessly with other popular frameworks and libraries, such as jQuery, AngularJS, and KnockoutJS.

In short, Web API is a great choice if you want to build modern, lightweight HTTP services that are easy to learn and use, and work seamlessly with a wide range of platforms and devices.

Differences between REST API and RESTful API

REST API and RESTful API might sound like the same thing, but there are a few key differences between the two.

A REST API is any API that follows the constraints of the REST architecture, which includes using HTTP verbs (GET, POST, PUT, DELETE) and resources identified in the request URI. A RESTful API is a specific type of REST API that also follows a set of conventions and constraints related to HTTP and REST.

In summary, all RESTful APIs are REST APIs, but not all REST APIs are necessarily RESTful.

Note: It's important to understand the differences when designing and implementing APIs, as well as when consuming them.

Advantages of using REST in a Web API

REST (Representational State Transfer) is a software architectural style that is used in designing APIs (Application Programming Interfaces) for the web. RESTful APIs provide several advantages over traditional APIs. Below are some advantages of using REST in a web API:

1. Simplicity: REST API uses a simple HTTP protocol which is easier to understand and use for developers.

2. Scalability: REST API can handle multiple clients simultaneously and thus can be easily scaled up or down depending on the need.

3. Flexibility: REST API allows clients to interact with the server asynchronously. The server can return data in different formats such as XML, JSON, or plain text.

4. Caching: REST API supports caching of responses, which can reduce the number of requests sent to a server and improve performance.

5. Stateless: REST API is stateless. This means that there is no need for the server to remember the client's previous requests. Each request is independent and self-contained.

6. Security: REST API provides a higher level of security as it uses standard HTTP methods such as GET, POST, PUT, and DELETE, which are well-defined and understood.

Overall, REST provides a practical and straightforward way to build web APIs that are scalable, flexible, and secure.

Understanding REST and SOAP

REST (Representational State Transfer) and SOAP (Simple Object Access Protocol) are two different web service communication protocols used for exchanging data over the internet.

REST is a lightweight web service protocol that uses HTTP to exchange data. It relies on a client-server architecture where the client initiates a request for a resource and the server responds with the requested data in a simple format such as XML or JSON.

SOAP, on the other hand, is a more heavy-duty protocol used for exchanging structured data between applications. It uses XML for message exchange and requires a lot of bandwidth as compared to REST. SOAP also supports advanced security features like authentication and encryption.

The main difference between REST and SOAP is that REST is a simpler, lighter-weight protocol that is better suited for web-based interaction, while SOAP is a more complex, heavyweight protocol that is better suited for enterprise-level services with advanced security requirements. Additionally, while SOAP is often used in a centralized, tightly controlled enterprise environment, REST is often used in more flexible, decentralized environments.

What is Web API 2.0?

Web API 2.0 is a framework developed by Microsoft as a part of the ASP.NET stack. It allows developers to build and consume HTTP services, commonly known as web APIs. These APIs are used to represent resources such as data, images, or text, and provide a simple and consistent way to exchange data between client and server applications. With Web API 2.0, developers have access to a range of features such as routing, content negotiation, and authentication, which makes it easy to create robust and scalable web applications.

Explanation of Media Type Formatters

Media Type Formatters are used in Web API to control the serialization process when sending and receiving data in requests and responses. These formatters determine the format of data that can be sent or received in the request or response body.

In simpler terms, Media Type Formatters convert .NET objects to a specific data format, such as XML or JSON, when sending data from a server to a client or receiving data from a client to a server.

There are several built-in Media Type Formatters included in .NET Framework, such as XMLSerializer, JSONSerializer, along with custom formatters that can be created using MediaTypeFormatter base class.

By choosing the appropriate formatter, you can enable a wider range of client compatibility with your Web API.

Which Protocol is Supported by Web API?

The Web API supports several protocols, including HTTP and HTTPS. HTTP is the most commonly used protocol, which stands for Hypertext Transfer Protocol. HTTPS is a more secure version of HTTP that uses SSL/TLS encryption to protect the data sent between the client and server.

// Sample code for establishing a HTTP GET request using Web API

using (var client = new HttpClient())
    var response = await client.GetAsync("");
    string resContent = await response.Content.ReadAsStringAsync();
    // Reading response content in string format

Open-Source Libraries Used by Web API for JSON Serialization


// The most common open-source library used by Web API for JSON serialization is Newtonsoft.Json.

Plain text:

The most popular open-source library used by Web API for JSON serialization is Newtonsoft.Json.

Understanding XML and JSON

XML (eXtensible Markup Language) and JSON (JavaScript Object Notation) are both data interchange formats used for transmitting and storing data. XML uses tags to define elements and attributes within a document, while JSON uses key-value pairs to define objects and arrays.

Both formats have their own advantages and disadvantages depending on the specific use case and programming language. XML is known for its extensibility, strong schema support, and interoperability across different platforms and languages. JSON is favored for its simplicity, compactness, and ease of use with JavaScript.

Choosing between XML and JSON depends on a variety of factors such as performance needs, data structure complexity, and development team preferences. Many web APIs provide both formats as options for developers to choose from based on their specific requirements.

Understanding Web API Filters

Web API filters are a powerful feature of the ASP.NET Web API framework that allow developers to implement cross-cutting concerns, such as authentication, caching, and logging, in a modular and reusable way. Filters can be applied globally, controller-wide, or action-specific, and can be combined in any order to achieve complex behavior.

By using web API filters, developers can avoid duplicating code across multiple endpoints, improve code organization and separation of concerns, and simplify testing and maintenance. There are several types of filters available in Web API, including authentication filters, authorization filters, action filters, result filters, and exception filters.


A web API can be consumed by anyone with access to the internet and the necessary authentication credentials, which are often provided by the API provider. This includes developers, businesses, organizations, and individuals who want to access the data or functionality provided by the API.

How to Handle Errors in a Web API?

Errors are inevitable in any system, and a Web API is no exception. As a developer, it is crucial to handle errors in your API effectively to provide better user experience and avoid potential vulnerabilities. Here are some tips for handling errors in a Web API:

  1. Define error types and status codes: It is essential to standardize error types and status codes to ensure consistency across your API. For instance, you can use HTTP status codes such as 400 for bad requests, 401 for unauthorized access, and 500 for internal server errors.
  2. Return informative error messages: Error messages should contain meaningful information to help users understand what went wrong. Avoid returning generic messages that do not provide any useful insights to the users.
  3. Log errors: Logging errors is essential to monitor and diagnose problems in your application. Keep track of error details such as exception messages, stack traces, and request context.
  4. Use try-catch blocks: In C#, you can use try-catch blocks to handle exceptions and return appropriate error responses. Catch specific exception types and return customized error messages based on the error type.
  5. Handle errors asynchronously: If your API is asynchronous, ensure that errors are handled asynchronously too. Use Task.FromResult and Task.FromException to return successful and error responses respectively.
  6. Provide documentation: Lastly, provide documentation to your API consumers about error handling practices, error types, status codes, and error messages.

By following these tips, you can handle errors effectively in your Web API, which can improve user experience, reduce vulnerabilities, and minimize downtime.

How to Register an Exception Filter Globally

In order to register an exception filter globally, you can use the `set_exception_handler` function. This function allows you to set a global exception handler that will catch any uncaught exceptions thrown by your PHP code.

Here's an example of how to use `set_exception_handler` to register an exception filter globally:

getMessage(); }

// Register your global exception handler function set_exception_handler('my_exception_handler');

// The rest of your PHP code goes here...


In this example, we define a function called `my_exception_handler` that will handle any uncaught exceptions. We then register this function as the global exception handler using `set_exception_handler`.

From this point forward, any uncaught exceptions thrown by your PHP code will be caught and handled by the `my_exception_handler` function.

What is MVC? Comparison between MVC and Web API

MVC stands for Model-View-Controller, which is a software architectural pattern used for developing web applications. It divides the application into three interconnected components: the model, the view, and the controller. The model handles the data and business logic, the view displays the data to the user, and the controller handles user input and interacts with the model and view.

Web API, on the other hand, is a framework for building HTTP services that can be accessed from different clients, including web browsers and mobile devices. It allows developers to create RESTful web services that use standard HTTP verbs like GET, POST, PUT, and DELETE for communication.

The main difference between MVC and Web API is that MVC is used for building web applications, while Web API is used for building web services. MVC focuses on creating a user interface to interact with the data, while Web API focuses on exposing the data to the clients in a structured format.

MVC is a complete framework that includes all the required components for building web applications, while Web API is a lightweight framework that only focuses on creating web services. MVC provides a lot of features for creating complex web applications, while Web API provides a simple and easy-to-use interface for creating web services.

In summary, MVC and Web API are different frameworks used for different purposes. MVC is used for building web applications that require a user interface, while Web API is used for building web services that expose data to clients.

ASP.NET Web API Interview Questions

19. Can you explain what ASP.NET Web API is?

    ASP.NET Web API is a framework developed by Microsoft to build HTTP services that can be consumed by various clients, such as web browsers and mobile devices. It builds on top of the ASP.NET framework and uses the HTTP protocol as a communication mechanism between the client and the server. Web API is used to create RESTful services, which are stateless web services that rely on HTTP verbs to communicate with the client.

Advantages of Using ASP.NET Web API

ASP.NET Web API has several advantages for building web applications:

  1. It supports HTTP verbs such as GET, POST, PUT, and DELETE, which are used to manage resources.
  2. It is highly extensible and can be used with other frameworks such as SignalR and Entity Framework.
  3. It is easy to develop and has a lightweight architecture that allows for faster development and testing.
  4. It can be used for cross-platform development and can be hosted on IIS or self-hosted in the application itself.
  5. It supports content negotiation, which allows the API to send data in multiple formats such as JSON, XML, or CSV.
  6. It provides built-in support for OAuth and other authentication methods to secure API endpoints.
  7. It is compatible with a wide range of client-side technologies such as JavaScript, AJAX, and mobile devices.

Overall, ASP.NET Web API provides a powerful and flexible framework for building modern web applications with RESTful APIs.

New features in ASP.NET Web API 2.0

ASP.NET Web API 2.0 introduced several new features including Attribute Routing, CORS support, OWIN integration, IHttpActionResult interface, and support for Entity Framework 6. These features provide improved performance, security, and customization options for building RESTful APIs.

using System.Web.Http;
using System.Web.Http.Cors;

namespace YourNamespace.Controllers
    [EnableCors(origins: "*", headers: "*", methods: "*")]
    public class ExampleController : ApiController
        public IHttpActionResult Get(int id)
            // code to retrieve example data with the given id
            return Ok(exampleData);

        public IHttpActionResult Post([FromBody] ExampleModel example)
            // code to create a new example entry
            return Created(new Uri(Request.RequestUri + example.Id.ToString()), example);

What is the purpose of HttpResponseMessage in ASP.NET Web API?

In ASP.NET Web API, the HttpResponseMessage class represents an HTTP response that can be returned from a controller action. It allows us to customize the HTTP response message and provide additional metadata such as status codes, headers, and content. The HttpResponseMessage object provides a lot of flexibility in building HTTP responses, making it a powerful tool for building RESTful APIs.

Difference between ApiController and Controller

In ASP.NET Web API, the ApiController class is used to create APIs that return data in various formats like JSON, XML, etc. whereas regular Controller class is used to create views that return HTML pages.

ApiController uses different types of action methods such as Get(), Post(), Put(), Delete() etc. to handle HTTP requests whereas in Controller, action methods like ActionResult Index(), ActionResult About(), etc. are used to return views.

ApiController is used when APIs are required to be built and Controller is used when views are required to be built.

Understanding Caching and its Types

Caching is the process of storing frequently accessed data in a temporary storage area in order to reduce the response time and increase the system's performance. There are two main types of caching:

1. Client-side caching: In this type of caching, the browser stores the data in the cache memory of the user's device. Whenever the user accesses the same website again, the browser will first check the cache to see if it contains the requested data. If the data is already present, the browser will not make a fresh request to the server, instead, it will retrieve the data from the cache memory, resulting in faster load times.

2. Server-side caching: In this type of caching, the data is stored in the cache memory of the server itself. Whenever a user requests for data, the server checks its cache memory first before retrieving the latest data from the database or another data source. This helps to improve the response time of the server and reduce the load on the database or data source.

Caching is a crucial technique for improving the performance of web applications, especially those that generate a large amount of dynamic content. However, it's important to keep in mind that caching can have drawbacks, such as stale data and increased complexity, which need to be managed appropriately.

True/False: WCF has been replaced by ASP.NET Web API.

Main Return Types Supported in ASP.NET Web API

In ASP.NET Web API, there are several main return types that can be used to send data back to the client:


- Allows you to return a variety of HTTP responses, such as






, etc. You can also return custom responses by implementing this interface.


- Similar to


, but provides more flexibility in terms of controlling the response message.


- Returns an empty HTTP response with a status code of 204 (No Content).


- Used for asynchronous operations and allows you to return any of the above types wrapped in a




- You can return any serializable type as the response, such as a custom class or a collection. The response will be serialized to the format requested by the client, such as JSON or XML.

Understanding ASP.NET Web API Routing

ASP.NET Web API Routing is a mechanism provided by the framework to map incoming HTTP requests to the appropriate controller actions. It allows developers to define URL patterns and then match those patterns against incoming requests to determine which action to invoke. This enables the creation of RESTful APIs that are easy to understand and use. By default, a Web API controller's actions are mapped to HTTP methods in a convention-based manner, but developers can customize the routing to fit their specific needs.

Securing an ASP.NET Web API

To secure an ASP.NET Web API, there are several steps you can take:

1. Use HTTPS to encrypt communications between the client and the server. 2. Implement authentication and authorization for client requests using tools such as IdentityServer or JSON Web Tokens (JWTs). 3. Enforce proper validation and sanitization of all inputs to prevent injection attacks or other malicious actions. 4. Use secure passwords and store them using secure password hashing techniques. 5. Implement rate limiting to prevent brute force attacks or other types of attacks. 6. Regularly update the API and all related security components to stay current with the latest security best practices and protect against newly discovered vulnerabilities.


//Example of using JWT authentication
 public class MyApiController : ApiController
     // API methods here
 //Example of using IdentityServer authentication
 public class Startup
     public void Configuration(IAppBuilder app)
         var idConfig = new IdentityServerBearerTokenAuthenticationOptions
             Authority = "",
             RequiredScopes = new[] { "api_scope" }

Exception Filters in ASP.NET Web API

In ASP.NET Web API, Exception Filters are used to handle exceptions that may occur during the execution of an API request. These filters are implemented as classes that derive from the ExceptionFilterAttribute class.

When an exception is thrown during the processing of a Web API request, the runtime will look for an appropriate filter to handle the exception. If an exception filter is found, the filter will be executed and can then return a custom error response or perform other exception handling tasks.

Exception filters can be applied globally to an entire Web API application, or they can be applied to specific controllers or actions. This allows for flexible and efficient handling of exceptions across different parts of the application.

Here is an example of how to create a custom exception filter in ASP.NET Web API:

public class CustomExceptionFilter : ExceptionFilterAttribute
    public override void OnException(HttpActionExecutedContext actionExecutedContext)
        // Perform custom exception handling here
        // For example, log the exception or return a custom error response


To apply this filter globally to your entire Web API application, you can add it to the global filters collection in your WebApiConfig.cs file:

config.Filters.Add(new CustomExceptionFilter());

Alternatively, you can apply the filter to a specific controller or action by adding the filter attribute to the controller or action method:

public class MyController : ApiController
    // Controller code here...

public class MyController : ApiController
    public IHttpActionResult MyAction()
        // Action code here...

By using Exception Filters in ASP.NET Web API, you can easily handle exceptions and provide custom error handling to your API consumers.

.NET Frameworks supporting ASP.NET Web API

In general, any .NET framework version greater than or equal to 4.0 supports ASP.NET Web API. Specifically, the following versions are compatible:

.NET Framework 4

.NET Framework 4.5

.NET Framework 4.6

.NET Framework 4.7

.NET Framework 4.8

It is worth noting that ASP.NET Web API is included in the newer .NET Core framework, which is a cross-platform, high-performance, open-source framework.

Understanding HTTPConfiguration in Web API

In Web API, HTTPConfiguration is a class that provides a set of configurable options and properties for handling HTTP requests and responses. It allows you to customize the behavior of your Web API application by configuring settings such as routing, formatters, message handlers, filters, and other components that are involved in the request processing pipeline.

The HTTPConfiguration class is typically used to register routes, set up dependency injection, enable tracing, set up message handlers, and configure other aspects of your Web API application. It can be accessed from any part of your application, allowing you to easily modify its settings at runtime.

Here's a simple example of how you can use HTTPConfiguration to register a route for your Web API application:

using System.Web.Http;

public class MyWebApiConfig
    public static void Register(HttpConfiguration config)
        // Route configuration
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }

In this example, we create a new class called MyWebApiConfig that has a static method called Register that takes an instance of HTTPConfiguration as its parameter. Inside this method, we configure our routes using the MapHttpAttributeRoutes method, which enables attribute routing in our Web API application. We also set up a default route that maps to the controller and action specified in the URL.

By using HTTPConfiguration, you can make your Web API application more flexible and customizable, allowing you to tailor it to the specific needs of your application and users.

Can an ASP.NET Web API method return a view?

In ASP.NET Web API, it is not intended to return views, as it is designed to return data in various formats such as JSON and XML. Views are part of the MVC framework and are used for rendering HTML templates. Therefore, returning a view from a Web API method is not a recommended practice.

Instead of returning views, Web API methods should return data in a format that can be consumed by client applications, such as JSON or XML. This data can then be used to construct the views on the client-side.

However, if you still want to return views from Web API methods, you can do so by using the `HttpResponseMessage` object. You can create an instance of this object and set the `Content` property to a `ViewResult` object, which represents a view.

Here's an example:

public HttpResponseMessage GetView()
    HttpResponseMessage response = new HttpResponseMessage();
    ViewResult view = View("MyView", myModel);
    response.Content = new StringContent(view.ToString());
    response.Content.Headers.ContentType = new MediaTypeHeaderValue("text/html");
    return response;

In the example above, the `GetView` method returns an `HttpResponseMessage` object. The `Content` property is set to a `ViewResult` object that represents a view called `MyView`. The view is rendered using a model called `myModel`. Finally, the `ContentType` property of the `Content` object is set to `text/html` to indicate that the content is an HTML view.

Keep in mind that this approach is not recommended and should only be used in specific scenarios where returning a view from a Web API method is absolutely necessary.

Understanding Content Negotiation in ASP.NET Web API

Content negotiation in ASP.NET Web API refers to the process of selecting the best format of response data to return to a client based on the client's request. It involves the server and client agreeing on the format of the response data before it is sent.

Web API allows for content negotiation between the server and client using the Accept and Content-Type headers. The Accept header specifies the format that the client expects the data to be returned in, while the Content-Type header specifies the format of the data being sent from the client to the server.

By default, Web API supports JSON and XML formats for content negotiation, but it can be extended to support other formats by creating a custom formatter.

Overall, content negotiation is essential for creating a flexible Web API that can respond to a variety of client requests and ensure that the data sent is in the appropriate format and structure.

Understanding the Difference between HTTP GET and HTTP POST

HTTP GET and HTTP POST are two HTTP methods used for sending data from a client to a server. The main difference lies in how the data is transmitted.

HTTP GET - This method sends data in the URL string, and the data is visible to everyone in the URL field of the browser. This method is mainly used to retrieve data from the server. It is also a safe method, as it does not modify the server's data.

HTTP POST - This method sends data in the body of the request, making it more secure than HTTP GET. It is mainly used to submit data to be processed by the server, such as submitting a form. This method is not safe, as it modifies the server's data.

In summary, HTTP GET is used to retrieve data, while HTTP POST is used to modify data. It is essential to choose the appropriate method based on the type of data being sent and the desired outcome.

Cross-Origin Resource Sharing (CORS) in Web API

CORS is a mechanism that allows a server to specify who can access its resources and how. It stands for "Cross-Origin Resource Sharing" and is an HTTP-header based system. It's a security feature that prevents malicious sites from accessing data they shouldn't have access to. CORS applies to all Web-based APIs.

Method for validating all controls on a webpage

The method for validating all controls on a webpage can be called "validateAllControls" and it can take the following steps:

1. Get all the controls on the webpage 2. Loop through each control and validate it 3. If any control fails validation, set a boolean flag to false 4. Return the boolean flag to indicate whether all controls passed validation or not.

Here's an example implementation in Python:

def validate_all_controls():
    # Get all controls on the page
    controls = driver.find_elements_by_xpath("//input | //select | //textarea")

    # Set a flag to indicate if any control fails validation
    all_controls_valid = True

    # Loop through each control and validate it
    for control in controls:
        if not control.is_valid():
            all_controls_valid = False
            # Print an error message for the control that failed validation
            print(f"Validation error for control {control.get_attribute('name')}")

    # Return the boolean flag to indicate if all controls passed validation or not
    return all_controls_valid

Note: This is just an example implementation and may need to be tailored to the specific requirements of your project.

Available Parameters for API URLs

Here are some of the parameters that can be passed in the URL of an API:


sets the maximum number of items to return


sets the starting point for retrieving results


specifies the sorting order of the results


narrows down the results based on certain criteria


performs a search for a specific query


specifies a JSONP callback function

These parameters may vary depending on the API you are using.

Understanding the Purpose of DelegatingHandler in C#

In C#, DelegatingHandler is a class that represents an HTTP message handler used to process HTTP requests. It provides a way to handle incoming and outgoing messages in the pipeline.

The primary use of DelegatingHandler is to provide additional functionality to an HTTP client or server, such as authentication, logging or adding headers to an HTTP request. It can intercept the request and response messages and modify them if needed.

DelegatingHandler is part of the ASP.NET Web API framework, and it is used to build RESTful services. It is customizable, making it a flexible tool for developers to use.

Overall, DelegatingHandler is an essential class in the world of C# programming, particularly for those who work with HTTP requests and responses.

Library Used for JSON Serialization in Web API

In Web API, the Newtonsoft.Json library is commonly used for JSON serialization.

Handling Errors Using HTTPError in Web API

In a Web API, there are different methods to handle errors, one of which is using the `HTTPError` method.

Here is an example of how to use `HTTPError` method in Python:

from flask import Flask, abort

app = Flask(__name__)

def example():
    # Check if the user is authorized, otherwise raise a 401 error
    if not authorized():

    # Return data
    return "Example Response"

# Error handler for 401 errors
def unauthorized(error):
    return "Unauthorized Access", 401

In this example, we define a route `/example` which requires authorization to access. If the user is not authorized, we raise a `401` error using the `abort()` function.

We also define an error handler for `401` errors using the `@app.errorhandler()` decorator. This error handler returns a custom response to the client when a `401` error occurs.

It is important to handle errors properly in a Web API to provide a good user experience and enhance the security of the application.

How to Unit Test a Web API?

Unit testing a web API is essential to ensure that it works as intended. Here are the steps to unit test a web API:

  1. Create a unit test project in your solution.
  2. Add the required references and dependencies to the unit test project.
  3. Write unit tests for each endpoint in the API.
  4. Use a tool like NUnit or xUnit to run the tests.
  5. Mock dependencies or use a test database to ensure that the tests are isolated and repeatable.
  6. Verify that the API returns the expected response for a given input.

By following these steps, you can ensure that your web API is working correctly and catch any bugs before they make it to production.


This section provides the summary of the main points discussed in the document.

The conclusions drawn from this research are that...

In light of these findings, it is recommended that...

Overall, this study contributes to the current knowledge about...

Further research is needed in order to...

Thank you for reading!

// Any additional code or resources can be added here

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