Interview Q&A

Short answer: Statelessness → Each request is independent; the server doesn’t store client state.

Explain a bit more

Client-Server Architecture → Separation of concerns between client UI and server logic. Uniform Interface → Standard HTTP methods and URIs. Cacheable → Responses can be cached to improve performance. Layered System → APIs can use intermediaries (like load balancers, proxies). Resource-based → Everything is treated as a resource (like users, orders, products).

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: uthorization: Bearer <token>

Real-world example (ShopNest)

ShopNest mobile app sends a JWT Bearer token. The API validates it and uses the user id from claims to load that user’s cart only.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Client sends token in Authorization header: Authorization: Bearer <token>

Real-world example (ShopNest)

ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: REST → Lightweight, uses HTTP, usually JSON, easy to use, stateless. SOAP → Protocol-based, uses XML, more complex, built-in security & transactions. REST is more flexible and widely used for web and mobile apps.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Docker allows running ASP.NET Core apps in containers, portable across environments. Dockerfile Example: # Build stage FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build WORKDIR /app COPY *.csproj ./ RUN dotnet restore COPY .

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Configuration providers are components that load configuration data from various sources.

Explain a bit more

Built-in Providers: JSON files (appsettings.json) Environment variables Command-line arguments In-memory collections Azure Key Vault User Secrets (for local dev) Custom providers (you can build your own) builder.Configuration .AddJsonFile("appsettings.json") .AddEnvironmentVariables() .AddCommandLine(args); Each provider plugs into the same configuration system, so you can access everything via IConfiguration. Configuration providers are components that load configuration data from various sources. Built-in Providers: JSON files (appsettings.json) Environment variables Command-line arguments In-memory collections Azure Key Vault User Secrets (for local dev) Custom providers (you can build your own)

Example code

builder.Configuration .AddJsonFile("appsettings.json") .AddEnvironmentVariables() .AddCommandLine(args); Each provider plugs into the same configuration system, so you can access everything via IConfiguration. Configuration providers are components that load configuration data from various sources. Built-in Providers: JSON files (appsettings.json) Environment variables Command-line arguments In-memory collections Azure Key Vault User Secrets (for local dev) Custom providers (you can build your own) Example: builder.Configuration .AddJsonFile("appsettings.json") .AddEnvironmentVariables() .AddCommandLine(args); Each provider plugs into the same configuration system, so you can access everything via IConfiguration. Configuration providers are components that load configuration data from various sources. Built-in Providers: JSON files (appsettings.json) Environment variables Command-line arguments In-memory collections Azure Key Vault User Secrets (for local dev) Custom providers (you can build your own) Example: builder.Configuration .AddJsonFile("appsettings.json") .AddEnvironmentVariables() .AddCommandLine(args); Each provider plugs into the same configuration system, so you can access everything via IConfiguration. 🔐 3. How do you manage secrets in development? In development, never store passwords, API keys, or connection strings in code or ppsettings.json. Use User Secrets — a safe way to store secrets outside the project tree. 🧰 4. What is User Secrets in ASP.NET Core? User Secrets are a local, developer-only configuration storage that keeps sensitive data out of source control. Setup: Enable secrets: dotnet user-secrets init

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15.

Explain a bit more

How do you pass data from controller to view?

Example code

public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15. How do you pass data from controller to view? public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15. How do you pass data from controller to view? public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15. How do you pass data from controller to view? You can use: public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15. How do you pass data from controller to view? You can use: public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15. How do you pass data from controller to view? public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15. How do you pass data from controller to view? You can use: public class LogActionFilter : ActionFilterAttribute public override void OnActionExecuting(ActionExecutingContext context) Console.WriteLine($"Action: {context.ActionDescriptor.DisplayName}"); Use it: [LogActionFilter] public IActionResult Index() => View(); 📤 15. How do you pass data from controller to view? You can use:

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Hangfire or Quartz.NET for Background Jobs Hangfire

Example code

app.UseHangfireDashboard(); RecurringJob.AddOrUpdate(() => Console.WriteLine("Recurring job"), Cron.Daily); Quartz.NET: Supports cron-like scheduling and clustered execution.

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: How to Test Minimal APIs? Answer: Minimal APIs are tested using WebApplicationFactory or TestServer. Example: var factory = new WebApplicationFactory<Program>();

Example code

var client = factory.CreateClient();
var response = await client.GetAsync("/products");
var products = await response.Content.ReadFromJsonAsync<List<Product>>(); Assert.NotEmpty(products);

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Stateless means the server does not store client session data. Each request must contain all the necessary information (like authentication tokens). This makes APIs scalable and reliable.

Real-world example (ShopNest)

ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Health Checking in ASP.NET Core builder.Services.AddHealthChecks() .AddSqlServer(connectionString) .AddCheck<CustomHealthCheck>("CustomCheck"); app.MapHealthChecks("/health"); Custom Health Check Example: public class CustomHealthCheck : IHealthCheck

Example code

{
public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken token) => Task.FromResult(HealthCheckResult.Healthy("Everything OK")); }

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: How to Use Serilog or NLog? Serilog Example (Program.cs): builder.Host.UseSerilog((ctx, lc) => lc .WriteTo.Console() .WriteTo.File("logs/log-.txt", rollingInterval: RollingInterval.Day) ); NLog

Example code

Install NLog.Extensions.Logging package Add NLog.config file Configure in Program.cs: builder.Logging.ClearProviders(); builder.Logging.SetMinimumLevel(LogLevel.Information); builder.Host.UseNLog(); ✅ Both support structured logging, sinks, filtering, and rolling files.

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: What Frameworks Are Commonly Used? Answer: xUnit – Popular, lightweight, supports parallel testing. NUnit – Rich assertion library. MSTest – Microsoft-supported, integrated in Visual Studio. Most modern ASP.NET Core projects use xUnit + Moq.

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Compiled queries improve performance by caching query translation.

Example code

private static readonly Func<AppDbContext, decimal, IEnumerable<Product>> _getExpensiveProducts = EF.CompileQuery((AppDbContext ctx, decimal price) => ctx.Products.Where(p => p.Price > price)); var result = _getExpensiveProducts(_context, 1000); 🔍 19. Pool Size=5; uthentication & Authorization

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Platform-independent (works across web, mobile, IoT). Simple, flexible, and scalable. Uses existing HTTP infrastructure. Lightweight (JSON/XML). Supports caching for better performance.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Rate Limiting Middleware in .NET 8 builder.Services.AddRateLimiter(options => { options.GlobalLimiter = PartitionedRateLimiter.Create<HttpContext, string>(httpContext => RateLimitPartition.GetFixedWindowLimiter(httpContext.Connection.Remo teIpAddress?.ToString()!, _ => new FixedWindowRateLimiterOptions { PermitLimit = 10, Window = TimeSpan.FromMinutes(1), QueueLimit = 2 })); }); app.UseRateLimiter(); ✅ Helps protect…

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: How to Enable Application Insights? Answer: Application Insights provides monitoring, telemetry, and tracing. Setup: builder.Services.AddApplicationInsightsTelemetry(builder.Configurati on["APPINSIGHTS_INSTRUMENTATIONKEY"]); Features: Track requests, exceptions, and dependencies Live metrics and dashboards Custom events and telemetry

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: How to Use Moq for Mocking Dependencies? Answer: Moq creates fake implementations of interfaces to control behavior during tests. Example: var mockRepo = new Mock<IProductRepository>(); mockRepo.Setup(x => x.GetAll()).Returns(new List<Product> { new Product { Id = 1, Name = "Laptop" } });

Example code

var service = new ProductService(mockRepo.Object);
var products = service.GetAll(); Assert.Single(products); ✅ Use .Setup(), .Verify(), and .Returns() to simulate behavior.

Real-world example (ShopNest)

ShopNest admin screens use MVC: controller loads data, Razor view renders HTML, Tag Helpers build forms safely.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Easier to learn & implement. Supports multiple formats (JSON, XML, plain text). Faster (less overhead). Works seamlessly with modern web & mobile apps. Better performance due to caching & statelessness.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Suppose we have a User Service API: GET /users → Get all users GET /users/1 → Get user with ID=1 POST /users → Create a new user PUT /users/1 → Update user with ID=1 DELETE /users/1 → Delete user with ID=1 This shows how CRUD operations map directly to HTTP methods.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: HATEOAS (Hypermedia As The Engine Of Application State) means responses contain links to related actions/resources. 👉

Example code

{ "id": 1, "name": "John", "links": [ { "rel": "self", "href": "/users/1" }, { "rel": "orders", "href": "/users/1/orders" } } This helps clients navigate APIs dynamically.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Common methods: API Keys → Simple tokens. Basic Auth → Username & password (not secure without HTTPS). OAuth 2.0 / OpenID Connect → Standard protocols for secure access. JWT (JSON Web Tokens) → Widely used for stateless authentication.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: GET → Used to retrieve data, should not modify server state, and can be cached/bookmarked. POST → Used to create new resources or submit data. It modifies server state, is not idempotent, and cannot be cached.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: 200 OK → If the resource was successfully deleted and a response body is returned. 204 No Content → If the resource was deleted but no body is needed. 404 Not Found → If the resource does not exist.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Safe → Because it only retrieves data without modifying server state. Idempotent → Multiple GET requests have the same result; no side effects occur.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.