Comprehensive Interview Questions for .NET Full Stack Developer (Angular/Azure/SQL)

 

I. .NET Core & C#

1. Dependency Injection:

   • Explain the DI container in .NET Core. How do you register a service with a scoped lifetime?

   • Follow-up: What are the differences between Singleton, Scoped, and Transient lifetimes?

2. Middleware & Pipeline:

   • Describe the request pipeline in ASP.NET Core. How would you create custom middleware for logging?

3. API Development:

   • How do you implement JWT authentication in a .NET Core Web API?

   • Code Task: Write a controller action for a RESTful POST endpoint that validates model state.

4. Performance & Security:

   • How do you prevent SQL injection in .NET Core?

   • What is the async/await pattern? Explain deadlock risks and mitigation.

5. Advanced C#:

   • Explain the differences between IEnumerable, ICollection, and IList.

   • When would you use a record vs. a class?

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II. Angular (TypeScript/HTML/CSS)

1. Component Lifecycle:

   • Describe Angular’s ngOnInit vs. ngAfterViewInit. When would you use ngOnChanges?

2. State Management:

   • How do you manage state in Angular without external libraries? Explain BehaviorSubject and async pipe.

   • Scenario: Share data between sibling components.

3. RxJS & Observables:

   • Convert a promise-based HTTP call to an Observable. How do you handle errors using catchError?

   • Explain operators: switchMap vs. mergeMap.

4. Performance Optimization:

   • How do you implement lazy loading for modules?

   • What is change detection strategy? When to use OnPush?

5. Directives & Pipes:

   • Create a custom structural directive. How do you create a pure vs. impure pipe?

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III. Azure Cloud Services

1. App Services & Deployment:

   • How do you deploy an Angular/.NET Core app to Azure App Service?

   • Explain deployment slots and blue-green deployment.

2. Azure SQL & Cosmos DB:

   • Compare Azure SQL Database with Cosmos DB. When would you choose one over the other?

   • How do you secure database connections using Managed Identities?

3. Serverless & Integration:

   • Describe a use case for Azure Functions in a microservices architecture.

   • How do you use Azure Service Bus for decoupling services?

4. Storage Solutions:

   • When would you use Azure Blob Storage vs. Azure Table Storage?

   • How do you implement CDN for static assets?

5. Monitoring & DevOps:

   • Configure Application Insights for an Angular/.NET app. What metrics would you track?

   • Set up CI/CD pipelines in Azure DevOps (YAML vs. classic editor).

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IV. SQL & Database Design

1. Query Optimization:

   • Optimize a slow-running query with multiple joins. How do indexes improve performance?

   • Scenario: Diagnose deadlocks in SQL Server.

2. Database Design:

   • Design schema for an e-commerce system (products, orders, users).

   • Explain normalization vs. denormalization trade-offs.

3. Advanced SQL:

   • Write a query to find duplicates in a table.

   • Compare INNER JOIN, LEFT JOIN, and CROSS APPLY.

4. Transactions & ACID:

   • Implement a transaction in T-SQL. How do you handle rollbacks?

   • What is isolation level READ COMMITTED SNAPSHOT?

5. Azure SQL Specifics:

   • How do you configure geo-replication?

   • Explain DTU vs. vCore purchasing models.

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V. Full Stack Architecture & Scenarios

1. System Design:

   • Design a scalable file-upload service using Angular, .NET Core, and Azure Blob Storage.

   • How would you secure API endpoints using OAuth 2.0?

2. Microservices:

   • Compare monolithic vs. microservices architectures. When is microservices overkill?

   • How do you manage inter-service communication (gRPC vs. REST)?

3. Caching Strategies:

   • Implement Redis caching in .NET Core for a high-read endpoint.

   • Cache invalidation approaches for dynamic data.

4. Testing:

   • Write a unit test for an Angular service using Jasmine.

   • Mock dependencies in a .NET Core controller with Moq.

5. Troubleshooting:

   • Debug a CORS issue between Angular and .NET Core API.

   • Diagnose latency in an Azure-deployed app.

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VI. Behavioral & Problem-Solving

1. Conflict Resolution:

   • Describe a time you disagreed with a technical decision. How did you handle it?

2. Learning & Adaptability:

   • How do you stay updated with Angular/.NET/Azure changes? Share a recent skill you learned.

3. Code Review:

   • What key issues do you look for in a PR (e.g., security, performance)?

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Tips for Interviewers:

• Coding Exercises:

  • Frontend: Build a reactive Angular form with validation.

  • Backend: Create a .NET Core API with pagination and filtering.

• Azure Scenario: Design a cost-optimized architecture for a traffic-spiky application.

• SQL Challenge: Optimize a 10-table join query and suggest indexing strategies.