.NET Core Interview Questions

Question 1

What is .NET Core vs .NET Framework?

Accepted Answer

.NET Core is cross-platform, open-source, and modular; .NET Framework is Windows-only with a larger but monolithic library. .NET Core: cross-platform, high performance, Docker support, side-by-side versioning. .NET Framework: Windows-only, WinForms/WPF/ASP.NET WebForms. .NET 5+ unified both. Migration: use .NET Upgrade Assistant. Choose .NET 8+ for all new projects.

Question 2

What is middleware in ASP.NET Core?

Accepted Answer

Middleware are components in the request pipeline that handle requests/responses: auth, logging, error handling, routing. Pipeline: app.Use()/app.Map()/app.Run(). Built-in: UseAuthentication, UseAuthorization, UseStaticFiles, UseCors. Custom: RequestDelegate, next() pattern. Order matters: exception handling first, auth before authorization. Short-circuit: don't call next() to stop pipeline.

Question 3

What is SignalR?

Accepted Answer

SignalR enables real-time web communication: WebSockets, Server-Sent Events, and long polling with automatic fallback. Hubs: server-side classes clients connect to. Clients: JavaScript, .NET, Java. Features: group messaging, connection management, streaming (IAsyncEnumerable). Scale-out: Redis backplane, Azure SignalR Service. Use for: chat, notifications, live dashboards, collaborative editing.

Question 4

What is Blazor?

Accepted Answer

Blazor builds interactive web UIs with C# instead of JavaScript, running on server (SignalR) or client (WebAssembly). Blazor Server: C# runs on server, UI updates via SignalR. Blazor WASM: C# compiled to WebAssembly, runs in browser. Blazor United (.NET 8): combines both with auto mode. Components: .razor files with C# and HTML. Benefits: share code between client/server, use .NET ecosystem, type safety.

Question 5

How do you implement CQRS in .NET?

Accepted Answer

CQRS separates read (query) and write (command) models using MediatR for dispatching commands and queries to handlers. Command: CreateOrderCommand → handler validates, saves to write DB. Query: GetOrderQuery → handler reads from optimized read model. MediatR: mediator pattern library. Benefits: independent scaling, optimized read models, event sourcing compatibility. Use when: complex domains, different read/write patterns. Overkill for simple CRUD.

Question 6

How do you deploy .NET Core to production?

Accepted Answer

Containerize with Docker, use CI/CD (GitHub Actions/Azure DevOps), deploy to Kubernetes or Azure App Service. Steps: (1) Dockerfile with multi-stage build. (2) CI/CD pipeline: build, test, publish. (3) Deploy: Azure App Service, AWS ECS, Kubernetes. (4) Configuration: environment variables, Azure Key Vault. (5) Health checks endpoints. (6) Logging: Serilog + Seq/Application Insights. (7) Monitoring: Prometheus/Grafana.

Question 7

Microsoft: What is Native AOT in .NET 8?

Accepted Answer

Native AOT compiles .NET directly to native machine code, eliminating JIT, reducing startup time and memory usage. Benefits: instant startup, smaller deployment size, no JIT overhead. Tradeoffs: no runtime code generation, limited reflection, longer build time. Ideal for: serverless/Lambda functions, CLI tools, microservices with fast startup requirements. Not all libraries compatible yet. PublishAot property in project file.

Question 8

Question 9

What is ASP.NET Core and how does it differ from ASP.NET?

Accepted Answer

ASP.NET Core is a cross-platform, high-performance rewrite of ASP.NET with built-in DI, middleware pipeline, and modular design. ASP.NET: Windows-only, IIS-dependent, System.Web monolith. ASP.NET Core: cross-platform (Windows/Linux/macOS), Kestrel web server, modular middleware pipeline, built-in DI, unified MVC + Web API, Razor Pages, Minimal APIs. Performance: ASP.NET Core is 10-100x faster than ASP.NET. Hosting: IIS, Nginx, Docker, Azure. .NET 8 LTS is current. Features: Native AOT, gRPC, Blazor, SignalR, Health Checks. Migration: incremental via YARP reverse proxy or System.Web adapters.

Question 10

What is the Kestrel web server?

Accepted Answer

Kestrel is ASP.NET Core's default cross-platform web server, built on libuv/IO completion ports for high-performance HTTP handling. Kestrel: default web server, cross-platform, supports HTTP/1.1, HTTP/2, HTTP/3. Can run standalone or behind reverse proxy (Nginx, IIS, Apache). Configuration: endpoints, TLS certificates, connection limits in appsettings.json or code. Performance: one of fastest web servers in TechEmpower benchmarks. Behind reverse proxy for: SSL termination, load balancing, static files, URL rewriting. Named pipes, Unix sockets supported. HTTPS: developer certificate for dev, Let's Encrypt or commercial for production.

.NET Core Course 2026 - Full Stack & Microservices

What You'll Learn

Career Opportunities

Course Completion Certificate

Course Modules Overview

.NET Core Fundamentals & Setup

Advanced C# & .NET Core Features

ASP.NET Core Web Development

Entity Framework Core & Database

Web APIs & RESTful Services

Microservices & Containerization

Cloud Integration & DevOps

Testing & Quality Assurance

Advanced Patterns & Best Practices

Real-time Applications with SignalR

Microservices with Dotnet Core

Dotnet Core Career and Best Practices

Course Curriculum

.NET Core Fundamentals & Setup

Advanced C# & .NET Core Features

ASP.NET Core Web Development

Entity Framework Core & Database

Web APIs & RESTful Services

Microservices & Containerization

Cloud Integration & DevOps

Testing & Quality Assurance

Advanced Patterns & Best Practices

Real-time Applications with SignalR

Microservices with Dotnet Core

Dotnet Core Career and Best Practices

Your Learning Path

Beginner

Intermediate

Advanced

Tools & Technologies

Visual Studio Code

Visual Studio 2022

Docker

Azure

GitHub Actions

Postman

Ready to Start Learning?

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