Mastering Angular and ASP.NET Core: Top 150+ Interview Questions for 2025

 

Topic 1: Angular Interview Questions

Angular questions focus on core framework elements, from basic setup to advanced optimizations. We've included sufficient examples within questions to illustrate concepts, making them analytical and informative for readers at all levels.

Beginner Level Angular Questions

These cover basic understanding and foundational topics, often with simple examples for clarity.

1. What is Angular, and provide an example of a basic component declaration?
2. Explain the difference between Angular and AngularJS, using a simple data binding example.
3. What is TypeScript, and why is it used in Angular? Give an example of type declaration in a component.
4. Describe the key components of Angular architecture with a diagram-like explanation.
5. What are directives in Angular? Provide an example of a structural directive like *ngIf.
6. What is a component in Angular? Write a basic example of a component class and template.
7. Differentiate between Component and Directive with code snippets.
8. What is a template in Angular? Show an example of template interpolation with user data.
9. What is a module in Angular? Explain with an example of importing HttpClientModule.
10. List Angular lifecycle hooks and explain ngOnInit with a logging example.
11. What is data binding? Categorize types and give a two-way binding example with input fields.
12. What is metadata in Angular? Provide an example in a component decorator.
13. What is Angular CLI? Demonstrate creating a new project with CLI commands.
14. Differentiate constructor and ngOnInit with a service injection example.
15. What is a service in Angular? Create a simple logging service example.
16. Explain dependency injection in Angular with a hierarchical example.
17. What is the async pipe? Use it in a template with an observable example.
18. How do you choose between inline and external templates? Give pros/cons with examples.
19. What is the purpose of *ngFor directive? Loop over an array of user objects as example.
20. What is ngIf directive? Show conditional rendering with a boolean flag example.
21. What happens if you use a script tag inside a template? Explain with a security example.
22. What is interpolation? Interpolate a user name in a greeting message example.
23. What are template expressions? Evaluate a simple math expression in a template.
24. What are template statements? Handle a button click event example.
25. What are pipes? Transform a date string using date pipe example.
26. What is a parameterized pipe? Format currency with locale parameter example.
27. How do you chain pipes? Chain lowercase and titlecase on a string example.
28. What is a custom pipe? Create one to reverse a string with example usage.
29. Differentiate pure and impure pipes with a filtering example.
30. What is a bootstrapping module? Bootstrap a root component example.
31. What are observables? Subscribe to a timer observable example.
32. What is HttpClient? Fetch user data from an API endpoint example.
33. How do you read full response in HttpClient? Use observe: 'response' option example.
34. How do you perform error handling in HttpClient? Catch error in pipe example.
35. What is RxJS? Explain with a basic subject example.
36. What is subscribing? Subscribe to an HTTP observable with data logging.
37. What is an observable? Create a custom observable from array data.
38. What is an observer? Implement next, error, complete methods example.
39. Differentiate promise and observable with async data fetch scenarios.
40. What is multicasting? Use share operator on a cold observable example.
41. How do you handle errors in observables? Use catchError operator example.
42. What is the shorthand for subscribe? Use async pipe in template example.
43. What are RxJS utility functions? Use fromEvent for button clicks example.
44. What are observable creation functions? Use of() with array data example.
45. What happens if no handler is supplied for observer? Simulate error scenario.
46. What are Angular elements? Convert a component to custom element example.
47. What is browser support for Angular Elements? List compatible browsers.
48. What are custom elements? Define one with shadow DOM example.
49. Do you need to bootstrap custom elements? Explain auto-registration.
50. How do custom elements work internally? Describe polyfill usage.

Intermediate Level Angular Questions

These involve application features, with scenario-based examples like handling user inputs or routing in a dashboard app.

1. What are HttpInterceptors? Intercept API calls for auth token addition scenario.
2. How do you share data between components? Use @Input/@Output in parent-child scenario.
3. What is NoopZone? Use in testing without change detection scenario.
4. What are macros in Angular? Define a reusable animation macro example.
5. What is the common module's purpose? Import for forms in a feature module scenario.
6. What compilers are used in Angular? Compare JIT vs AOT in build scenarios.
7. What is the role of SPA in Angular? Navigate pages without reload example.
8. What is content projection? Project content into a card component scenario.
9. What are Decorators in Angular? Use @Component with metadata example.
10. What are pure Pipes? Transform data only on input change scenario.
11. What are impure pipes? Handle async data updates in template scenario.
12. What is Eager vs Lazy Loading? Load modules on demand in large app scenario.
13. What is Angular Material? Style a button with mat-button example.
14. What is transpiling? Convert TypeScript to JS in build process scenario.
15. What is Change Detection? Trigger on user input change scenario.
16. When to use a directive? Create custom validator for form field scenario.
17. Do you always need a Routing Module? Set up basic routes in small app.
18. What is JIT compilation? Compile at runtime in dev mode scenario.
19. What happens if same module imported twice? Explain singleton services.
20. What ways to trigger change detection? Use detectChanges in tests scenario.
21. Difference between ngIf and ngSwitch? Switch on user role enum example.
22. Difference between ViewChild and ContentChild? Query projected content scenario.
23. What is Angular Universal? Render server-side for SEO in blog app.
24. Difference between ngOnChanges and ngOnInit? Log input changes example.
25. What is Angular Ivy? Enable in tsconfig for faster builds scenario.
26. Difference between ViewEncapsulation and Shadow DOM? Style isolation example.
27. What is a route guard? Protect admin route with auth check scenario.
28. Purpose of NgModule decorator? Declare components in module example.
29. Difference between HttpClient and Http? Modern vs legacy HTTP handling.
30. Purpose of ng-container? Group elements without extra DOM node scenario.
31. Difference between async pipe and subscribe? Handle observable in template.
32. What is a resolver? Pre-fetch data before route activation scenario.
33. What is a provider? Provide service at component level example.
34. Difference between service and component? Inject service into component.
35. Difference between ElementRef and Renderer2? Safe DOM manipulation scenario.
36. Difference between template-driven and reactive forms? Validate user signup form.
37. What is Angular service worker? Cache assets for offline app scenario.
38. Difference between template and view? Render dynamic view example.
39. What is a template reference variable? Access input value in form submit.
40. What is ViewChild decorator? Query child component in parent scenario.
41. What is NgZone? Run code outside Angular zone for performance.
42. Difference between ngOnInit and ngAfterViewInit? Init after view ready scenario.
43. Purpose of HostListener? Listen to host element click event example.
44. Purpose of ng-template? Render conditional template with ngIf scenario.
45. Purpose of ActivatedRoute? Get route params in component example.
46. Purpose of ngClass? Apply classes based on condition scenario.
47. What are reactive forms? Build a dynamic user profile form scenario.
48. What are template-driven forms? Simple login form with ngModel scenario.
49. Differences between reactive and template-driven forms? Validation complexity.
50. Purpose of FormBuilder? Inject to create form group example.

Expert Level Angular Questions

These are analytical, with real-life scenarios like optimizing large-scale apps or handling complex data flows.

1. Describe Angular authentication and authorization in a multi-user app scenario.
2. What is the digest cycle? Optimize in high-frequency updates scenario.
3. Explain Angular CLI schematics for custom blueprint generation.
4. What is HttpClient multicasting? Share API response across subscribers.
5. What is server-side rendering? Implement in e-commerce site for SEO.
6. Best practices for security in Angular? Prevent XSS in user input scenario.
7. Various security contexts in Angular? Sanitize HTML content example.
8. How to handle errors globally? Use error handler service scenario.
9. Explain route events in a navigation logging scenario.
10. What is activated route? Snapshot vs subscribe to params change.
11. Purpose of Wildcard route? Handle 404 not found page scenario.
12. Types of compilation in Angular? AOT for production build optimization.
13. Advantages of AOT? Faster render in mobile app scenario.
14. Ways to control AOT compilation? Use ngc compiler flags.
15. Restrictions of metadata? Avoid private properties example.
16. Three phases of AOT? Code analysis, generation, template validation.
17. Can arrow functions be used in AOT? Limitations with this context.
18. Purpose of metadata JSON files? Ahead-of-time compilation artifacts.
19. Can any JS feature be used in AOT expressions? Restrictions on eval.
20. What is folding in AOT? Constant expression evaluation example.
21. What are Angular Signals? Reactive state management example.
22. Explain Angular animations with state transition scenario.
23. Steps to use animation module? Trigger fade-in on load example.
24. What is State function? Define idle and hover states.
25. What is Style function? Apply CSS in animation example.
26. Purpose of animate function? Time-based transition example.
27. What is transition function? From void to visible scenario.
28. How to inject dynamic script? Load external library at runtime.
29. Role of service worker? Progressive web app offline support.
30. Design goals of service workers? Reliable network handling.
31. Features in Ivy preview? Smaller bundles in large app scenario.
32. Can AOT be used with Ivy? Compatibility check.
33. What is Angular Language Service? IDE auto-complete example.
34. Install Angular Language Service? Package.json addition.
35. Editor support for Language Service? VS Code integration.
36. Features of Language Service? Diagnostics in templates.
37. Add web workers? Offload heavy computation scenario.
38. Limitations of web workers? No DOM access example.
39. What is Angular CLI Builder? Custom build process.
40. What is a builder? Extend ng build command.
41. Invoke a builder? Angular.json configuration.
42. Create app shell? Pre-render static parts for fast load.
43. What are case types? Upper/lower in pipes.
44. Class decorators in Angular? @Injectable example.
45. Class field decorators? @Input on properties.
46. What is declarable? Components, directives, pipes.
47. Restrictions on declarable classes? Export requirement.
48. What is a DI token? Custom injection key example.
49. What is Angular DSL? Template syntax internals.
50. What is RxJS Subject? Multicast data stream scenario.

Topic 2: Angular with ASP.NET Core Interview Questions

These questions emphasize integration, such as API consumption, authentication, and full-stack scenarios. Examples include real-world data flows like user registration systems.

Beginner Level Angular with ASP.NET Core Questions

Basic setup and integration concepts with simple examples.

1. What is ASP.NET Core? Integrate with Angular for SPA example.
2. Explain CLR in .NET. How it supports Angular backend.
3. Difference between ASP.NET Core and traditional ASP.NET? Migration scenario.
4. What is middleware in ASP.NET Core? Use for logging in API calls.
5. How to create a basic ASP.NET Core Web API? Endpoint for user list.
6. What is Kestrel? Host Angular-built app example.
7. Difference between IIS and Kestrel? Deployment choices.
8. What is Startup class in ASP.NET Core? Configure services example.
9. How to enable CORS in ASP.NET Core? Allow Angular frontend access.
10. What is Razor Pages? Compare to Angular routing.

Intermediate Level Angular with ASP.NET Core Questions

Practical integration scenarios, like API consumption in Angular apps.

1. How to consume ASP.NET Core API in Angular? HttpClient get users scenario.
2. Implement authentication in full-stack app? JWT token flow example.
3. What is Entity Framework Core? Integrate with Angular for CRUD operations.
4. How to handle file uploads? Angular form to ASP.NET Core endpoint.
5. Scenario: User logs in via Angular, calls secure API—explain token refresh.
6. Difference between Use and Run in middleware? Short-circuit request example.
7. What is ViewChild in Angular for integration? Query form before API submit.
8. Challenges in .NET with Angular? Version compatibility scenario.
9. How to deploy Angular with ASP.NET Core? Azure app service example.
10. Scenario: Optimize API response for Angular grid—use pagination.
11. What is SignalR? Real-time chat integration with Angular.
12. How to validate models in ASP.NET Core? Bind to Angular reactive form.
13. Scenario: Handle 500 errors from API in Angular—use interceptor.
14. What is Dependency Injection in ASP.NET Core? Service for Angular calls.
15. Scenario: Share session state between Angular and ASP.NET Core.

Expert Level Angular with ASP.NET Core Questions

Advanced, scenario-based with performance and security focus.

1. Scenario: Scale Angular-ASP.NET app for 10k users—caching strategies.
2. How to implement OAuth in integration? Google login flow example.
3. Scenario: Debug CORS issues in production—tools and steps.
4. What is gRPC in ASP.NET Core? Compare to REST for Angular consumption.
5. Scenario: Migrate monolithic .NET app to microservices with Angular frontend.
6. How to use Blazor with Angular? Hybrid app scenario.
7. Scenario: Secure API against XSS/CSRF in Angular calls.
8. Performance drop in live app—troubleshoot ASP.NET Core side.
9. Scenario: Implement role-based access—Angular guards with API claims.
10. How to handle multi-language support? Resource files in .NET, i18n in Angular.
11. Scenario: Real-time data sync—use WebSockets with example payload.
12. What is Minimal APIs in ASP.NET Core? Integrate with Angular observables.
13. Scenario: Optimize bundle size for Angular app served by ASP.NET.
14. How to implement logging in full-stack? Serilog in .NET, console in Angular.
15. Scenario: Handle database migrations with EF Core during Angular updates.

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