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.NET interview prep for engineers in India

PrepHike · 6 min read

If you write C# for a living and still earn less than your skill is worth, the gap is usually not your code. It is how you answer when a panel probes ASP.NET Core internals, EF Core behaviour, or how your microservices actually talk. Here is what India panels really test.

What .NET interviews in India actually test

There are roughly three kinds of .NET panels you will face in India. Enterprise services firms (the large IT companies and their captive arms) test breadth: can you discuss the request pipeline, dependency injection, and how EF Core tracks entities without fumbling. Product companies test depth on a few things: concurrency, memory, and how you reason about a slow endpoint. GCCs (the global capability centres of foreign banks, retailers, and SaaS firms, now paying some of the best packages in the country) sit in between, but they push hard on system design, cloud, and security because the code runs in production they care about.

The thing that costs engineers money is not failing a hard question. It is answering an easy one in a way that sounds junior. "I used Entity Framework for the database" tells a panel nothing. "We used EF Core with split queries because the default join was duplicating rows and blowing up the result set" tells them you have actually shipped. The questions below are the ones that decide which bucket you land in.

ASP.NET Core and Web API: the pipeline questions

Almost every asp.net core interview opens here, because it separates people who configured a template from people who understand it. Expect:

• Middleware order. Why does UseAuthentication have to come before UseAuthorization, and what breaks if you call UseRouting in the wrong place. Panels love this because the answer reveals whether you picture the pipeline as an ordered chain of delegates or as magic.
• DI lifetimes. The classic trap: injecting a scoped service into a singleton. Be ready to say why that captures a stale instance and how a captive dependency causes bugs that only show up under load. Know Transient, Scoped, and Singleton with a real example of each from your own work.
• Model binding and validation. Where validation runs, how [ApiController] changes the default behaviour, and why you should not trust client input even after binding succeeds.
• Async all the way. What actually happens when you call .Result on a task in a request thread, and why that deadlocks or starves the thread pool. This is a common c# interview india filter because so many codebases still block on async.

One concrete number worth carrying into the room: if you have ever moved an endpoint from synchronous to async and watched throughput change, say it. "Under a load test, p95 dropped from around 1.2s to under 400ms once we stopped blocking on I/O" lands far harder than reciting the keyword async.

EF Core: where most candidates quietly lose points

EF Core questions are a favourite because everyone claims it and few can defend it. The common ones:

• The N+1 problem. Explain how lazy loading inside a loop fires one query per row, and how Include, projection, or split queries fix it. If you can describe a time you found one in production by reading the SQL it generated, you are ahead of most senior candidates.
• Change tracking. When to use AsNoTracking for read-only queries and what it saves. This connects to memory and speed, which product panels care about.
• IQueryable vs IEnumerable. The moment a query executes in the database versus in memory, and how calling .ToList() too early pulls a whole table across the wire.
• Migrations in a team. How you handle migration conflicts, and whether you run them at startup or as a separate deploy step. GCC panels ask this because it is an operational scar they have all felt.

MS SQL and Redis: the data layer

Behind EF Core sits MS SQL, and panels go straight to fundamentals. Be fluent on clustered versus non-clustered indexes, why a covering index helps a specific query, and how to read an execution plan well enough to spot a table scan. Know the isolation levels and what a deadlock actually is, with the deadlock you debugged ready to tell.

Redis questions are about knowing when not to cache. Talk about cache-aside, TTLs, and the stampede problem when a hot key expires and a thousand requests hit the database at once. If you used Redis for distributed locks or rate limiting, mention it, but be honest about the trade-offs because someone will push.

Microservices, CQRS, and messaging

This is where GCC and product panels separate a 18 LPA offer from a 30 LPA one. They are not testing whether you can say "microservices." They are testing whether you know the cost.

• Why you split, and why you might not. A good answer admits that a monolith is often the right call, and that you split when teams or scaling needs diverge. Panels respect engineers who do not cargo-cult.
• Service communication. Synchronous HTTP versus a message broker, and what happens to a request when a downstream service is down. Know retries, idempotency, and the outbox pattern.
• CQRS. When separating reads from writes earns its complexity, and how MediatR is commonly used in .NET to structure commands and queries. Be ready to say where CQRS is overkill, because that honesty reads as senior.
• Distributed transactions. Why two-phase commit is avoided and how the saga pattern handles a multi-service workflow that can fail halfway.

If you want to rehearse the diagram-on-a-whiteboard part, our system design checklist walks through the structure panels expect, and it maps cleanly onto a .NET stack.

Azure, OAuth2/JWT, and OWASP

Cloud and security questions are now standard, not bonus. On Azure, know the difference between App Service, Azure Functions, and AKS, and when you would pick each. Be able to discuss Key Vault for secrets, managed identities so you are not storing connection strings, and Application Insights for tracing a slow call across services.

On auth, the panel wants to hear OAuth2 and JWT explained without hand-waving: what is in a token, why you validate the signature and the issuer, how refresh tokens work, and why you never put sensitive data in a JWT payload since it is only encoded, not encrypted. On OWASP, be ready for SQL injection (and why parameterised queries or EF Core protect you), broken access control, and how you handle secrets. You do not need to recite the full top ten. You need two examples you have actually defended against.

How to prepare without drowning

The mistake is trying to revise all of .NET. You cannot, and the panel will not test all of it. The better path is to build a question bank from your own resume: for every technology you list, write the five questions a panel at your level will ask, and answer them out loud. We describe that process in building a skill Q&A bank, and pairing it with a tight project explanation covers most of what a .NET interview throws at you.

Before any of this, get honest about the number you are aiming for. If you are a strong .NET engineer at 9 LPA, the correction waiting for you might be 22 to 30 LPA at a GCC, and the preparation should match that target. Our market value audit helps you set a grounded number instead of guessing, and the SHIFT method turns that into a plan. When you are ready to pressure-test it, a structured diagnostic call will show you exactly where your answers still sound junior.

The panel is not deciding if you can write C#. They already assume you can. They are deciding how much to pay you for it, and that is decided by how clearly you explain what you have built.