Interview Q&A

Short answer: Anti-Forgery Tokens Protects against CSRF attacks In Razor: <form method="post"> @Html.AntiForgeryToken() </form> In API: use services.AddAntiforgery(), validate via [ValidateAntiForgeryToken]. 1⃣

Real-world example (ShopNest)

ShopNest’s product edit form posts to an MVC action. Model binding fills a ProductEditVm; the action validates and redisplay the view on errors.

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: Creating REST APIs in ASP.NET Core is straightforward using controllers or minimal PIs.

Explain a bit more

Example: Traditional Controller-Based API dotnet new webapi -n MyApi Program.cs: var builder = WebApplication.CreateBuilder(args); builder.Services.AddControllers(); var app = builder.Build(); pp.MapControllers(); pp.Run(); Controller: [ApiController] [Route("api/[controller]")] public class ProductsController : ControllerBase { [HttpGet] public IActionResult GetAll() => Ok(new[] { "Laptop", "Phone" }); } ✅ You get RESTful endpoints automatically (GET /api/products). {

Example code

if (!ModelState.IsValid)
return BadRequest(ModelState);
return CreatedAtAction(nameof(CreateOrder), new { id = 1 }, order); }
} 📦 3. How does content negotiation work? Content negotiation allows clients to request responses in a specific format (JSON, XML, etc.) using the Accept header. SP.NET Core automatically picks the best formatter: GET /api/products ccept: application/json Response → JSON GET /api/products ccept: application/xml Response → XML (if XML formatter is added) Enable XML Support: builder.Services.AddControllers() .AddXmlSerializerFormatters(); 🧭 4. How to handle versioning in APIs? You can version APIs to maintain backward compatibility using the Microsoft.AspNetCore.Mvc.Versioning package. Install: dotnet add package Microsoft.AspNetCore.Mvc.Versioning Configure: builder.Services.AddApiVersioning(options => {
options.DefaultApiVersion = new ApiVersion(1, 0);
options.AssumeDefaultVersionWhenUnspecified = true;
{ [HttpGet] public IActionResult Get() => Ok("Version 1");
} ⚠ 5. What is ProblemDetails? ProblemDetails is a standardized JSON structure for API error responses (RFC 7807). Example Output: { "type": " "title": "Resource not found", "status": 404, "detail": "Product with ID 5 was not found" } Usage: return NotFound(new ProblemDetails
{ Title = "Product not found", Status = StatusCodes.Status404NotFound, Detail = "The product ID 5 does not exist." }); 🚦 6. How to return custom HTTP status codes? You can use built-in helpers from ControllerBase: Method Status Code Ok() 200 Created() / CreatedAtAction() 201 NoContent() 204 BadRequest() 400 Unauthorized() 401 NotFound() 404 StatusCode(500) Custom Example: return StatusCode(503, "Service temporarily unavailable"); 📄 7. How to implement pagination in APIs? Pagination helps manage large datasets efficiently. Example: [HttpGet] public IActionResult GetProducts([FromQuery] int page = 1, [FromQuery] int size = 10) {
var data = _context.Products .Skip((page - 1) * size) .Take(size) .ToList(); var totalCount = _context.Products.Count(); Response.Headers.Add("X-Total-Count", totalCount.ToString()); return Ok(data);
} ✅ Supports GET /api/products?page=2&size=5. 🔐 8. How to secure APIs with JWT tokens? Use JWT (JSON Web Token) authentication for stateless security. Setup in Program.cs: builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationS cheme) .AddJwtBearer(options => { options.TokenValidationParameters = new TokenValidationParameters { ValidateIssuer = true, ValidIssuer = " ValidateAudience = true, ValidAudience = " IssuerSigningKey = new SymmetricSecurityKey( Encoding.UTF8.GetBytes("super-secret-key")) }; }); Then protect controllers: [Authorize] [ApiController] [Route("api/[controller]")] public class OrdersController : ControllerBase
{ [HttpGet] public IActionResult GetOrders() => Ok("Secure data");
} ⚡ 9. What is rate limiting in .NET 8? .NET 8 introduces built-in rate limiting middleware to control API request rates. Example: builder.Services.AddRateLimiter(options => { options.AddFixedWindowLimiter("fixed", opt => {
opt.PermitLimit = 5; // 5 requests
opt.Window = TimeSpan.FromSeconds(10); // per 10 seconds
var exception = context.Features.Get<IExceptionHandlerFeature>()?.Error; return Results.Problem(title: "Unexpected error", detail: exception?.Message); }); Or write a custom middleware for consistent error formatting. 🧾 11. How to use Swagger / OpenAPI? Swagger generates interactive API documentation automatically. Setup: builder.Services.AddEndpointsApiExplorer(); builder.Services.AddSwaggerGen(); var app = builder.Build();
if (app.Environment.IsDevelopment())
{ pp.UseSwagger(); pp.UseSwaggerUI(); } Run → Navigate to ✅ You can test endpoints directly from the browser. 🧰 12. What is NSwag or Swashbuckle? Both tools generate OpenAPI/Swagger documentation, but with slight differences: Tool Description Swashbuckle.AspNetCor Most common; adds Swagger UI, docs, and JSON schema NSwag Adds extra features like client SDK generation for C#/TypeScript Example (NSwag client generation): nswag openapi2csclient /input: /output:Client.cs 📤 13. How to upload files via Web API? Use IFormFile for file uploads. Controller Example: [HttpPost("upload")] public async Task<IActionResult> UploadFile(IFormFile file)
{
if (file == null || file.Length == 0)
return BadRequest("No file uploaded.");
var path = Path.Combine("wwwroot/uploads", file.FileName);
using var stream = new FileStream(path, FileMode.Create); wait file.CopyToAsync(stream); return Ok(new { file.FileName, file.Length });
} Client sends multipart/form-data POST requests. 🌐 14. How to implement CORS? CORS (Cross-Origin Resource Sharing) allows requests from other domains (e.g., frontend pps). Enable in Program.cs: builder.Services.AddCors(options => { options.AddPolicy("AllowReactApp", policy => policy.WithOrigins(" .AllowAnyHeader() .AllowAnyMethod()); }); var app = builder.Build(); pp.UseCors("AllowReactApp"); ✅ Now your React or Angular frontend can call your API safely. 🚀 15. What’s new in .NET 8 Minimal APIs? Minimal APIs let you build lightweight REST endpoints without controllers — great for microservices. Example: var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

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: pp.UseAuthentication(); pp.UseAuthorization(); pp.UseAuthentication(); pp.UseAuthorization(); pp.UseAuthentication(); pp.UseAuthorization(); pp.UseAuthentication(); pp.UseAuthorization();

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: ASP.NET Core Identity is a membership system that manages users, passwords, roles, claims, and authentication.

Explain a bit more

It provides: User registration & login Password hashing Role & claims management Two-factor authentication Cookie & token-based authentication You can scaffold Identity to get ready-to-use pages for login, registration, and password reset. ASP.NET Core Identity is a membership system that manages users, passwords, roles, claims, and authentication. It provides: User registration & login Password hashing Role & claims management Two-factor authentication Cookie & token-based authentication

Example code

You can scaffold Identity to get ready-to-use pages for login, registration, and password reset. ASP.NET Core Identity is a membership system that manages users, passwords, roles, claims, and authentication. It provides: User registration & login Password hashing Role & claims management Two-factor authentication Cookie & token-based authentication Example: You can scaffold Identity to get ready-to-use pages for login, registration, and password reset. ⚙ 2. How do you configure Identity in ASP.NET Core? Add Identity services in Program.cs: builder.Services.AddDbContext<AppDbContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("Defa ultConnection"))); builder.Services.AddIdentity<ApplicationUser, IdentityRole>() .AddEntityFrameworkStores<AppDbContext>() .AddDefaultTokenProviders(); ASP.NET Core Identity is a membership system that manages users, passwords, roles, claims, and authentication. It provides: User registration & login Password hashing Role & claims management Two-factor authentication Cookie & token-based authentication Example: You can scaffold Identity to get ready-to-use pages for login, registration, and password reset. ⚙ 2. How do you configure Identity in ASP.NET Core? Add Identity services in Program.cs: builder.Services.AddDbContext<AppDbContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("Defa ultConnection"))); builder.Services.AddIdentity<ApplicationUser, IdentityRole>() .AddEntityFrameworkStores<AppDbContext>() .AddDefaultTokenProviders();

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: If you change appsettings.json and configuration reload is enabled, IOptionsMonitor picks up the new value without restarting the app. Entity Framework Core

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: MVC stands for Model–View–Controller, a design pattern that separates application logic into three layers: Model – Represents the data and business logic (e.g., Product, Customer, Order). View – The UI or presentation layer that displays data (Razor views). {

Example code

public IActionResult Details(int id)
{
var product = _service.GetById(id);
return View(product);
}
} Notes: Action methods cannot be private or static. They respond to routes like /Product/Details/5. 🎯 6. What are Action Results? An Action Result represents the response returned to the client — view, JSON, redirect, file, etc. SP.NET Core provides many result types: ViewResult JsonResult RedirectResult FileResult ContentResult StatusCodeResult 🔍 7. Difference between ViewResult, JsonResult, and ContentResult. Type Used For Example ViewResult Returns an HTML view return View("Details", model); JsonResult Returns JSON data return Json(model); ContentResul Returns plain text or custom content return Content("Hello World"); IActionResult is an interface that represents the result of an action method. It allows flexibility — you can return any kind of result (view, JSON, redirect, etc.) from the same method. Example: public IActionResult Index()
{
if (!User.Identity.IsAuthenticated)
return RedirectToAction("Login");
return View();
} 🧠 9. How does model binding work? Model binding automatically maps data from the HTTP request (query string, route, body, form) to method parameters or model objects. Example: public IActionResult Save(Product model)
{ // model properties are automatically filled _service.Add(model); return RedirectToAction("Index");
}
{ [Required] public string Name { get; set; } [Range(1, 10000)] public decimal Price { get; set; }
} In a controller: if (!ModelState.IsValid)
return View(model);

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: dotnet publish -c Release

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: Install package: dotnet add package Microsoft.Extensions.Caching.StackExchangeRedis

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: Caching improves performance by storing frequently used data in memory or external storage to reduce database or API calls. SP.NET Core provides:

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: Creating REST APIs in ASP.NET Core is straightforward using controllers or minimal APIs.

Explain a bit more

Traditional Controller-Based API dotnet new webapi -n MyApi Program.cs: var builder = WebApplication.CreateBuilder(args); builder.Services.AddControllers(); var app = builder.Build(); app.MapControllers(); app.Run(); Controller: [ApiController] [Route("api/[controller]")] public class ProductsController : ControllerBase [HttpGet] public IActionResult GetAll() => Ok(new[] { "Laptop", "Phone" }); ✅ You get RESTful endpoints automatically (GET /api/products). Creating REST APIs in ASP.NET Core is straightforward using controllers or minimal APIs.

Example code

Traditional Controller-Based API dotnet new webapi -n MyApi Program.cs: var builder = WebApplication.CreateBuilder(args); builder.Services.AddControllers(); var app = builder.Build(); app.MapControllers(); app.Run(); Controller: [ApiController] [Route("api/[controller]")] public class ProductsController : ControllerBase [HttpGet] public IActionResult GetAll() => Ok(new[] { "Laptop", "Phone" }); ✅ You get RESTful endpoints automatically (GET /api/products). Creating REST APIs in ASP.NET Core is straightforward using controllers or minimal APIs. Example: Traditional Controller-Based API dotnet new webapi -n MyApi Program.cs: var builder = WebApplication.CreateBuilder(args); builder.Services.AddControllers(); var app = builder.Build(); app.MapControllers(); app.Run(); Controller: [ApiController] [Route("api/[controller]")] public class ProductsController : ControllerBase [HttpGet] public IActionResult GetAll() => Ok(new[] { "Laptop", "Phone" }); ✅ You get RESTful endpoints automatically (GET /api/products). Creating REST APIs in ASP.NET Core is straightforward using controllers or minimal APIs. Example: Traditional Controller-Based API dotnet new webapi -n MyApi Program.cs: var builder = WebApplication.CreateBuilder(args); builder.Services.AddControllers(); var app = builder.Build(); app.MapControllers(); app.Run(); Controller: [ApiController] [Route("api/[controller]")] public class ProductsController : ControllerBase [HttpGet] public IActionResult GetAll() => Ok(new[] { "Laptop", "Phone" }); ✅ You get RESTful endpoints automatically (GET /api/products). 🧱 2. What is the [ApiController] attribute? [ApiController] simplifies building APIs by adding smart defaults: Automatic model validation → 400 Bad Request on invalid models Automatic [FromBody], [FromQuery], etc. inference Follow : ProblemDetails JSON response for errors Example: [ApiController] [Route("api/[controller]")] public class OrdersController : ControllerBase [HttpPost] public IActionResult CreateOrder(Order order) if (!ModelState.IsValid) return BadRequest(ModelState); return CreatedAtAction(nameof(CreateOrder), new { id = 1 }, order); 📦 3. How does content negotiation work? Content negotiation allows clients to request responses in a specific format (JSON, XML, etc.) using the Accept header. ASP.NET Core automatically picks the best formatter: GET /api/products Accept: application/json Response → JSON GET /api/products Accept: application/xml Response → XML (if XML formatter is added) Follow : Enable XML Support: builder.Services.AddControllers() .AddXmlSerializerFormatters(); 🧭 4. How to handle versioning in APIs? You can version APIs to maintain backward compatibility using the Microsoft.AspNetCore.Mvc.Versioning package. Install: dotnet add package Microsoft.AspNetCore.Mvc.Versioning Configure: builder.Services.AddApiVersioning(options => options.DefaultApiVersion = new ApiVersion(1, 0); options.AssumeDefaultVersionWhenUnspecified = true; options.ReportApiVersions = true; }); Use in controllers: [ApiVersion("1.0")] [Route("api/v{version:apiVersion}/products")] [ApiController] public class ProductsV1Controller : ControllerBase [HttpGet] public IActionResult Get() => Ok("Version 1"); ⚠ 5. What is ProblemDetails? Follow : ProblemDetails is a standardized JSON structure for API error responses (RFC 7807). Example Output: "type": " "title": "Resource not found", "status": 404, "detail": "Product with ID 5 was not found" Usage: return NotFound(new ProblemDetails Title = "Product not found", Status = StatusCodes.Status404NotFound, Detail = "The product ID 5 does not exist." }); 🚦 6. How to return custom HTTP status codes? You can use built-in helpers from ControllerBase: Method Status Code Ok() 200 Created() / CreatedAtAction() 201 NoContent() 204 BadRequest() 400 Unauthorized() 401 Follow : NotFound() 404 StatusCode(500) Custom Example: return StatusCode(503, "Service temporarily unavailable"); 📄 7. How to implement pagination in APIs? Pagination helps manage large datasets efficiently. Example: [HttpGet] public IActionResult GetProducts([FromQuery] int page = 1, [FromQuery] int size = 10) var data = _context.Products .Skip((page - 1) * size) .Take(size) .ToList(); var totalCount = _context.Products.Count(); Response.Headers.Add("X-Total-Count", totalCount.ToString()); return Ok(data); ✅ Supports GET /api/products?page=2&size=5. 🔐 8. How to secure APIs with JWT tokens? Use JWT (JSON Web Token) authentication for stateless security. Follow : Setup in Program.cs: builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationS cheme) .AddJwtBearer(options => options.TokenValidationParameters = new TokenValidationParameters ValidateIssuer = true, ValidIssuer = " ValidateAudience = true, ValidAudience = " IssuerSigningKey = new SymmetricSecurityKey( Encoding.UTF8.GetBytes("super-secret-key")) }); Then protect controllers: [Authorize] [ApiController] [Route("api/[controller]")] public class OrdersController : ControllerBase [HttpGet] public IActionResult GetOrders() => Ok("Secure data"); ⚡ 9. What is rate limiting in .NET 8? .NET 8 introduces built-in rate limiting middleware to control API request rates. Example: builder.Services.AddRateLimiter(options => Follow : options.AddFixedWindowLimiter("fixed", opt => opt.PermitLimit = 5; // 5 requests opt.Window = TimeSpan.FromSeconds(10); // per 10 seconds opt.QueueLimit = 0; }); }); var app = builder.Build(); app.UseRateLimiter(); app.MapGet("/api/data", () => "Hello") .RequireRateLimiting("fixed"); ✅ Prevents abuse or DDoS attacks by throttling requests. 🚨 10. How do you handle exceptions in APIs? Use global exception handling middleware instead of try/catch everywhere. Example: app.UseExceptionHandler("/error"); app.Map("/error", (HttpContext context) => var exception = context.Features.Get<IExceptionHandlerFeature>()?.Error; return Results.Problem(title: "Unexpected error", detail: exception?.Message); }); Or write a custom middleware for consistent error formatting. Follow : 🧾 11. How to use Swagger / OpenAPI? Swagger generates interactive API documentation automatically. Setup: builder.Services.AddEndpointsApiExplorer(); builder.Services.AddSwaggerGen(); var app = builder.Build(); if (app.Environment.IsDevelopment()) app.UseSwagger(); app.UseSwaggerUI(); Run → Navigate to ✅ You can test endpoints directly from the browser. 🧰 12. What is NSwag or Swashbuckle? Both tools generate OpenAPI/Swagger documentation, but with slight differences: Tool Description Swashbuckle.AspNetCor Most common; adds Swagger UI, docs, and JSON schema NSwag Adds extra features like client SDK generation for C#/TypeScript Example (NSwag client generation): Follow : nswag openapi2csclient /input: /output:Client.cs 📤 13. How to upload files via Web API? Use IFormFile for file uploads. Controller Example: [HttpPost("upload")] public async Task<IActionResult> UploadFile(IFormFile file) if (file == null || file.Length == 0) return BadRequest("No file uploaded."); var path = Path.Combine("wwwroot/uploads", file.FileName); using var stream = new FileStream(path, FileMode.Create); await file.CopyToAsync(stream); return Ok(new { file.FileName, file.Length }); Client sends multipart/form-data POST requests. 🌐 14. How to implement CORS? CORS (Cross-Origin Resource Sharing) allows requests from other domains (e.g., frontend apps). Enable in Program.cs: builder.Services.AddCors(options => Follow : options.AddPolicy("AllowReactApp", policy => policy.WithOrigins(" .AllowAnyHeader() .AllowAnyMethod()); }); var app = builder.Build(); app.UseCors("AllowReactApp"); ✅ Now your React or Angular frontend can call your API safely. 🚀 15. What’s new in .NET 8 Minimal APIs? Minimal APIs let you build lightweight REST endpoints without controllers — great for microservices. Example: var builder = WebApplication.CreateBuilder(args); var app = builder.Build(); app.MapGet("/products", () => new[] { "Phone", "Tablet" }); app.MapPost("/products", (Product product) => Results.Created($"/products/{product.Id}", product)); app.Run(); New in .NET 8: Route groups for grouping endpoints Input validation with [Validate] attributes Enhanced OpenAPI (Swagger) support Rate limiting, Authorization, and Filters integration Follow : Typed results for consistent HTTP responses ✅ Minimal APIs now rival traditional controllers for small, fast APIs. Performance & Caching

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: ASP.NET Core configuration is flexible, layered, and environment-aware.

Explain a bit more

It reads settings from multiple sources (JSON files, environment variables, command-line rgs, etc.) and merges them into a single configuration object (IConfiguration).

Example code

In Program.cs: var builder = WebApplication.CreateBuilder(args); // Access configuration var appName = builder.Configuration["AppSettings:Name"]; SP.NET Core automatically loads:

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: builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationS cheme) .AddJwtBearer(options => { options.TokenValidationParameters = new TokenValidationParameters { ValidateIssuer = true, ValidateAudience = true, ValidateLifetime = true, ValidateIssuerSigningKey = true, ValidIssuer = " ValidAudience = " IssuerSigningKey = new… SymmetricSecurityKey(……… Encoding.UTF8.GetBytes("super-secret-key-123")) }; });…

Explain a bit more

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationS cheme) .AddJwtBearer(options => { options.TokenValidationParameters = new TokenValidationParameters { ValidateIssuer = true, ValidateAudience = true, ValidateLifetime = true, ValidateIssuerSigningKey = true, ValidIssuer = " ValidAudience = " IssuerSigningKey = new SymmetricSecurityKey( Encoding.UTF8.GetBytes("super-secret-key-123")) }; }); builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationS cheme) .AddJwtBearer(options => { options.TokenValidationParameters = new TokenValidationParameters { ValidateIssuer = true, ValidateAudience = true,…

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: var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build();…

Explain a bit more

app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization();

Example code

var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization(); var app = builder.Build(); app.UseAuthentication(); app.UseAuthorization();

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: options.UseLazyLoadingProxies().UseSqlServer(...); options.UseLazyLoadingProxies().UseSqlServer(...); options.UseLazyLoadingProxies().UseSqlServer(...); options.UseLazyLoadingProxies().UseSqlServer(...);

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: Middleware vs Filters vs Handlers Concept When It Runs Scope Example Middleware Before/after request Global Logging, authentication Filters Around controller/action Controller/action Authorization, validation Handlers Authentication/Authorization Global or endpoint JWT handler, Cookie auth 1⃣

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: dotnet publish -c Release -o C:\inetpub\wwwroot\MyApp

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: builder.Services.AddStackExchangeRedisCache(options => { options.Configuration = "localhost:6379"; }); builder.Services.AddStackExchangeRedisCache(options => { options.Configuration = "localhost:6379"; }); builder.Services.AddStackExchangeRedisCache(options => { options.Configuration = "localhost:6379"; });… builder.Services.AddStackExchangeRedisCache(options => { options.Configuration = "localhost:6379"; });

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: Environment variables are great for overriding settings at deployment time (especially in Docker or Azure). Example: set ASPNETCORE_ENVIRONMENT=Production set ConnectionStrings__Default="Server=mydb;Database=App;User=sa;Passwor d=123" Notice the double underscores __ for nested keys. {

Example code

private readonly IWebHostEnvironment _env;
public HomeController(IWebHostEnvironment env)
{
_env = env;
}
public IActionResult Index()
{
if (_env.IsDevelopment())
return Content("Running in Development mode");
return Content($"Environment: {_env.EnvironmentName}");
}
} You can also access it in Program.cs: if (builder.Environment.IsProduction())
{ // Configure production services } 🧾 8. How to use different appsettings.json files? ASP.NET Core supports environment-specific JSON files. Example structure: ppsettings.json ppsettings.Development.json ppsettings.Staging.json ppsettings.Production.json Program.cs: builder.Configuration .AddJsonFile("appsettings.json") .AddJsonFile($"appsettings.{builder.Environment.EnvironmentName}.jso n", optional: true); t runtime, only the file matching the current environment will override base settings. Example: ppsettings.json { "AppName": "MyApp", "LogLevel": "Information" } ppsettings.Production.json { "LogLevel": "Error" } Result in Production → LogLevel = Error. 🔄 9. How to reload configuration dynamically? You can make JSON configuration files auto-reload when changed. Example: builder.Configuration.AddJsonFile("appsettings.json", optional: false, reloadOnChange: true); If you update appsettings.json, the new values are reflected automatically in your app without restarting. You can subscribe to changes using IOptionsMonitor (see below). 📦 10. How to bind configuration to POCO classes? You can map sections of your configuration directly to C# classes (POCOs). Example: ppsettings.json { "AppSettings": { "SiteName": "TechStore", "PageSize": 20, "EnableCache": true }
} Create a POCO: public class AppSettings
{
public string SiteName { get; set; }
public int PageSize { get; set; }
public bool EnableCache { get; set; }
} Bind configuration: builder.Services.Configure<AppSettings>( builder.Configuration.GetSection("AppSettings")); Inject it into a controller: public class HomeController : Controller
{
private readonly AppSettings _settings;
public HomeController(IOptions<AppSettings> options)
{
_settings = options.Value;
}
public IActionResult Index()
{
return Content($"Welcome to {_settings.SiteName}!");
}
} You can also use IOptionsSnapshot for per-request reload or IOptionsMonitor for live updates. Web APIs & REST

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: [Authorize] [ApiController] [Route("api/[controller]")] public class OrdersController : ControllerBase { [HttpGet] public IActionResult GetOrders() => Ok("Secured Orders"); } [Authorize] [ApiController] [Route("api/[controller]")] public class OrdersController : ControllerBase { [HttpGet] public IActionResult GetOrders() =>… Ok("Secured Orders"); }… [Authorize] [ApiController] [Route("api/[controller]")] public…

Explain a bit more

class OrdersController : ControllerBase { [HttpGet] public IActionResult GetOrders() => Ok("Secured Orders"); } [Authorize] [ApiController] [Route("api/[controller]")] public class OrdersController : ControllerBase { [HttpGet] public IActionResult GetOrders() =>… Ok("Secured Orders"); }

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 ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get;…

Explain a bit more

set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } }

Example code

public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } } public class ApplicationUser : IdentityUser { public string FullName { get; set; } }

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: Use compiled queries for frequently executed queries.? is a common interview topic in ASP.NET Core MVC. Give a clear definition, then one concrete example.

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 virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; }

Example code

public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; } public virtual Category Category { get; set; }

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: SignalR vs WebSockets Feature WebSockets SignalR Protocol Low-level TCP-based High-level abstraction Transpor Only WebSockets Fallbacks: WebSockets → SSE → Long Polling Usage Real-time messages Real-time hubs with automatic reconnection, grouping, scaling ✅ Use SignalR for apps needing broadcast, connection management, and fallbacks.

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 Host in Azure App Service? Answer: Azure App Service provides PaaS hosting for ASP.NET Core apps. Steps: Publish the app via Visual Studio, CLI, or GitHub Actions. dotnet publish -c Release Create App Service in Azure portal. Deploy using FTP, Git, or CI/CD pipelines. App Service automatically configures Kestrel + reverse proxy. ✅ Supports scaling, HTTPS, and monitoring out-of-the-box.

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: pp.MapHealthChecks("/health"); pp.MapHealthChecks("/health"); pp.MapHealthChecks("/health"); pp.MapHealthChecks("/health"); pp.MapHealthChecks("/health"); pp.MapHealthChecks("/health"); pp.MapHealthChecks("/health"); pp.MapHealthChecks("/health");

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.