Preparing for an ASP.NET interview can feel overwhelming, especially with the vast range of concepts, coding techniques, and real-world scenarios that might come up. Whether you’re a fresher stepping into your first job or an experienced developer aiming for a senior role, having a clear understanding of ASP.NET fundamentals and advanced topics will boost your confidence.

In this blog, we’ve compiled 50+ most frequently asked ASP.NET interview questions along with clear, concise answers to help you prepare effectively.

Basic ASP.NET Interview Questions

1. What is ASP.NET?

ASP.NET is an open-source, server-side web application framework developed by Microsoft that allows developers to build dynamic web pages, web applications, and web services using .NET languages like C# and VB.NET.

2. What are the main features of ASP.NET?

Rich toolbox and designer in Visual Studio
Server-side controls and events
State management
Caching for performance
Security through authentication and authorization

3. Difference between ASP.NET Web Forms and MVC?

Web Forms: Event-driven, uses server controls, tightly coupled with UI.
MVC: Model-View-Controller architecture, clean separation of concerns, supports test-driven development.

4. What are ASP.NET server controls?

Server controls are objects on ASP.NET web pages that run on the server and render HTML to the browser. Examples: TextBox, Button, GridView.

5. What is ViewState?

ViewState is a method of preserving page and control values between postbacks in ASP.NET Web Forms.

6. What are HTTP Handlers in ASP.NET?

HTTP Handlers process incoming HTTP requests at a lower level than pages, handling specific request types (e.g., images, files).

7. Explain the ASP.NET Page Life Cycle.

Page Request
Start
Initialization
Load
Postback Event Handling
Rendering
Unload

8. What is Global.asax?

It’s an optional file for handling application-level events like Application_Start, Session_Start, Application_Error.

9. What is Web.config?

A configuration file used to manage settings like connection strings, session state, security, and custom errors.

10. What are Master Pages in ASP.NET?

Master Pages provide a consistent layout for multiple web pages, defining common UI elements.

Intermediate ASP.NET Interview Questions

11. What is ASP.NET MVC?

A design pattern that separates the application into Model, View, and Controller components for cleaner code and easier testing.

12. What is Routing in ASP.NET MVC?

Routing maps incoming browser requests to a specific controller action using URL patterns.

13. Explain Razor View Engine.

Razor is a markup syntax that allows embedding server-side code in web pages using @ symbols in .cshtml files.

14. What are Partial Views?

Reusable view components that can be rendered inside other views.

15. What is TempData in ASP.NET MVC?

TempData stores data temporarily and is available for the duration of a single request and the subsequent one.

16. Difference between Session and Application state?

Session State: Stores data for a single user session.
Application State: Stores data shared across all users of the application.

17. What is Bundling and Minification?

A technique to improve performance by combining multiple CSS/JS files into one (bundling) and removing unnecessary characters (minification).

18. What is Entity Framework in ASP.NET?

An Object-Relational Mapping (ORM) framework for accessing and manipulating databases using .NET objects.

19. What is Data Annotations in MVC?

Attributes used to define validation rules and display metadata for model properties.

20. How do you handle exceptions in ASP.NET MVC?

By using try-catch blocks, HandleError attribute, or custom error pages in web.config.

Advanced ASP.NET Interview Questions

21. What is Dependency Injection in ASP.NET Core?

A design pattern where objects receive their dependencies rather than creating them directly.

22. Explain Middleware in ASP.NET Core.

Middleware components process requests and responses in a pipeline, enabling cross-cutting features like authentication, logging, and error handling.

23. What is Tag Helper in ASP.NET Core?

A server-side feature that allows HTML-friendly syntax for generating dynamic content in Razor views.

24. Difference between .NET Framework and .NET Core?

.NET Framework: Windows-only, older version.
.NET Core: Cross-platform, open-source, faster, and modular.

25. What is SignalR?

A library for adding real-time web functionality to applications using WebSockets or fallback techniques.

26. What is the difference between Authentication and Authorization?

Authentication: Verifies who the user is.
Authorization: Determines what the user can do.

27. How do you secure an ASP.NET application?

Using HTTPS, authentication mechanisms, authorization roles, input validation, and anti-forgery tokens.

28. What is Kestrel?

A cross-platform web server for ASP.NET Core applications.

29. What is Web API in ASP.NET?

A framework for building RESTful services using HTTP.

30. How do you version APIs in ASP.NET Core?

By using URL versioning, query string parameters, or HTTP header versioning.

Performance & Optimization Questions

31. How do you improve performance in ASP.NET applications?

Use caching.
Minimize ViewState.
Optimize database queries.
Use asynchronous programming.

32. What is Output Caching?

Stores the dynamic page output and reuses it for future requests to reduce processing.

33. What is Lazy Loading in Entity Framework?

A technique where related data is loaded only when it’s accessed.

34. What is Eager Loading?

A method where related data is loaded immediately with the main entity.

35. How do you handle large file uploads in ASP.NET?

By increasing request limits in web.config and streaming file uploads.

36. What is Cross-Site Scripting (XSS)?

An attack where malicious scripts are injected into web pages.

37. What is CSRF in ASP.NET?

Cross-Site Request Forgery, where attackers trick users into performing actions without consent. Prevent using anti-forgery tokens.

38. How do you encrypt sensitive data in ASP.NET?

Using DataProtection API, hashing, or encryption libraries.

39. What is Role-Based Authorization?

Restricting access to certain features based on assigned user roles.

40. What is Claims-Based Authentication?

Authentication where identity is represented by a set of claims rather than a username/password alone.

Miscellaneous ASP.NET Questions

41. What is ASP.NET Core Identity?

A membership system for managing users, passwords, roles, and claims.

42. How do you configure logging in ASP.NET Core?

By using built-in logging providers like Console, Debug, and third-party options like Serilog.

43. What is Razor Pages?

A page-focused programming model in ASP.NET Core for building web apps.

44. How do you deploy ASP.NET Core applications?

Through IIS, Azure, Docker containers, or self-contained deployment.

45. What is the difference between synchronous and asynchronous code?

Synchronous: Blocks execution until the task completes.
Asynchronous: Frees the thread to do other work while waiting.

46. What is Middleware Ordering?

The sequence in which middleware components run in the request pipeline affects behavior.

47. What is gRPC in ASP.NET Core?

A high-performance RPC framework using HTTP/2.

48. What are Minimal APIs?

A feature in ASP.NET Core for building lightweight APIs with minimal code.

49. What is Blazor?

A framework for building interactive web UIs with C# instead of JavaScript.

50. What’s new in ASP.NET Core 7/8?

Performance improvements, minimal API enhancements, and better integration with cloud-native tools.

Conclusion

Mastering ASP.NET requires understanding both its foundational concepts and advanced capabilities. This collection of 50+ most asked ASP.NET interview questions covers a wide range of topics to help you feel confident and well-prepared. Whether you’re tackling your first ASP .net Interview Question or discussing advanced ASP.NET Core features, this guide will give you a strong edge in your next interview.

50+ Most Asked ASP.NET Interview Questions with Answers