Interview practice

.NET Developer

2–5 years · Mid — C# · ASP.NET Core · Entity Framework · SQL Server · LINQ · Azure

ownership A migration experience 1 of 6

Can you describe a migration you led, such as moving from one database to another or updating a framework version? What were the hurdles?

What a strong answer covers

Describes the migration context and objectives; identifies specific technical hurdles encountered; explains the strategies implemented to address these hurdles; reflects on outcomes and any unforeseen issues; provides insight into team collaboration during the process.

The follow-up you would get

What would you do to better prepare for the migration next time?

Could you have answered that?

scenario Async programming 2 of 6

You have an async method that is supposed to retrieve data from multiple sources, but it times out under load. How do you investigate the issue?

What a strong answer covers

Analyzes the method for potential blocking calls; reviews the implementation of Task.WhenAll for handling multiple tasks; checks the execution time of each external call; inspects any throttling or rate limiting from the sources; considers adding cancellation tokens to enhance responsiveness.

The follow-up you would get

The timeouts were caused by one of the services being unresponsive. What strategies can you implement to handle such scenarios?

Could you have answered that?

technical Dependency Injection 3 of 6

In your ASP.NET Core application, you notice that a singleton service is holding on to state that should be scoped to the request. What steps do you take to rectify this?

What a strong answer covers

Identifies the service lifetime mismatch; changes the service registration from singleton to scoped; ensures that the service is not being accessed in a static context; checks for unintended shared state between requests; tests the application for thread safety after the change.

The follow-up you would get

What are the implications of sharing state in a singleton service?

Could you have answered that?

ownership A feature you owned end to end 4 of 6

Describe a feature you were responsible for delivering from start to finish. What challenges did you encounter?

What a strong answer covers

Details the specific feature and its context; outlines the key challenges faced during development; explains the solutions implemented to overcome these challenges; reflects on lessons learned; discusses the impact of the feature on users or the business.

The follow-up you would get

What would you approach differently if given another chance?

Could you have answered that?

scenario Azure deployment 5 of 6

Your deployment to Azure fails due to a configuration issue, and the error message is vague. Walk me through your first steps.

What a strong answer covers

Checks deployment logs for specific error codes; verifies resource group and service configurations; inspects Azure App Service settings; reviews application settings for connection strings and secrets; determines if a rollback is necessary and how to communicate the issue.

The follow-up you would get

The configuration error was caused by a missing environment variable. How do you prevent this from happening again?

Could you have answered that?

technical API Design 6 of 6

You are tasked with designing a RESTful API for a new feature that requires creating, reading, updating, and deleting resources. What key considerations do you take into account?

What a strong answer covers

Defines clear resource URIs and HTTP methods for CRUD operations; ensures idempotency for PUT and DELETE methods; implements proper status codes for responses; considers pagination for large datasets; validates input using model binding and data annotations.

The follow-up you would get

How do you handle versioning of your API?

Could you have answered that?

That is this set.

Load six more — you will get questions you have not seen first.

Give me six more →

Say your answer out loud before revealing. Reading the answer first feels like learning and is not.