Syllabus

ASP.NET Core Complete Tutorial (ShopNest)

Module 1: Foundations
What is ASP.NET Core? Complete Guide Setting Up ASP.NET Core Development Environment ASP.NET Core Project Structure Explained MVC Architecture in ASP.NET Core — Complete Guide Controllers and Actions in ASP.NET Core Routing in ASP.NET Core — Conventional and Attribute Routing Views and Razor Syntax in ASP.NET Core Layouts, Partial Views and View Components Models and ViewModels in ASP.NET Core Forms, Model Binding and Validation in ASP.NET Core Tag Helpers in ASP.NET Core — Complete Guide Static Files, Bundling and Minification in ASP.NET Core
Module 2: Entity Framework Core
Entity Framework Core — Introduction and Setup EF Core Code First — Models, Migrations, Database EF Core CRUD Operations — Create, Read, Update, Delete EF Core LINQ Queries — Beginner to Advanced EF Core Relationships — One-to-One, One-to-Many, Many-to-Many EF Core Fluent API — Advanced Configuration EF Core Repository Pattern and Unit of Work EF Core Performance Optimization Database First Approach with EF Core (Scaffold) EF Core with SQL Server — Advanced Features
Module 3: Dependency Injection & Middleware
Dependency Injection in ASP.NET Core — Complete Guide Middleware in ASP.NET Core — Complete Guide Configuration in ASP.NET Core — appsettings, Environment Variables, Secrets Filters in ASP.NET Core — Action, Authorization, Exception, Resource, Result Logging in ASP.NET Core — ILogger, Serilog, NLog Error Handling and Exception Management in ASP.NET Core
Module 4: Authentication & Security
ASP.NET Core Identity — Complete Setup Guide Authentication in ASP.NET Core — Cookie and JWT Authorization in ASP.NET Core — Roles, Policies, Claims JWT Authentication with Refresh Tokens — Complete Implementation OAuth2 and External Login (Google, Facebook, Microsoft) Data Protection and Encryption in ASP.NET Core HTTPS, SSL Certificates and Security Best Practices
Module 5: Web API
Building REST APIs with ASP.NET Core — Complete Guide API Versioning in ASP.NET Core Swagger / OpenAPI Documentation in ASP.NET Core Input Validation in Web APIs — FluentValidation and Data Annotations Pagination, Filtering and Sorting in ASP.NET Core APIs HTTP Client and Consuming External APIs in ASP.NET Core Minimal APIs in ASP.NET Core .NET 8 SignalR — Real-Time Web Applications
Module 6: Advanced Architecture
Clean Architecture in ASP.NET Core CQRS Pattern with MediatR in ASP.NET Core Repository Pattern — Deep Dive with Generic Repository Background Services and Hosted Services in ASP.NET Core Caching in ASP.NET Core — In-Memory, Distributed, Redis Health Checks in ASP.NET Core AutoMapper in ASP.NET Core Microservices with ASP.NET Core — Introduction Message Queues with RabbitMQ / Azure Service Bus in ASP.NET Core gRPC with ASP.NET Core
Module 7: Testing
Unit Testing ASP.NET Core with xUnit and Moq Integration Testing in ASP.NET Core Testing EF Core — In-Memory vs SQLite Performance Testing and Load Testing ASP.NET Core APIs Test-Driven Development (TDD) in ASP.NET Core
Module 8: Deployment & DevOps
Deploying ASP.NET Core to IIS on Windows Server Docker and Containerization for ASP.NET Core Deploying ASP.NET Core to Azure App Service CI/CD with GitHub Actions for ASP.NET Core Azure SQL Database with ASP.NET Core Environment Configuration and Secrets Management
Module 9: Real-World Projects
Build a Complete Blog Website with ASP.NET Core MVC Build an E-Commerce Product Catalog API (ASP.NET Core Web API) Build a Student Management System (Complete CRUD App) Build a Job Portal (Full Stack ASP.NET Core) Build a REST API with Clean Architecture — Complete Guide Build a Real-Time Chat App with SignalR and ASP.NET Core
Module 10: Advanced Topics
Blazor WebAssembly and Blazor Server — Complete Guide gRPC, GraphQL and Alternative API Styles in ASP.NET Core Rate Limiting and API Throttling in ASP.NET Core .NET 8 Output Caching in ASP.NET Core .NET 8 ASP.NET Core .NET 9 New Features — Complete Guide
ASP.NET Core Complete Tutorial (ShopNest)
Lesson 25 of 75 33% of course

Configuration in ASP.NET Core — appsettings, Environment Variables, Secrets

1 · 5 min · 5/24/2026

Learn Configuration in ASP.NET Core — appsettings, Environment Variables, Secrets in our free ASP.NET Core Complete Tutorial (ShopNest) series. Step-by-step explanations, examples, and interview tips on Toolliyo Academy.

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Configuration in ASP.NET Core — appsettings, Environment Variables, Secrets — ShopNest
Article 25 of 75 · Module 3: Dependency Injection & Middleware · ShopNest Multi-Environment Deployment
Target keyword: asp.net core configuration · Read time: ~28 min · .NET: 8 / 9 · Project: ShopNest Multi-Environment Deployment

Introduction

ShopNest runs on your laptop, staging, and Azure production — each needs different connection strings and API keys. ASP.NET Core configuration merges JSON files, environment variables, and secrets with a clear priority order.

After this article you will

  • Structure appsettings.json and environment-specific files
  • Use IOptions, IOptionsSnapshot, IOptionsMonitor
  • Store dev secrets in User Secrets — never in Git
  • Bind complex configuration objects
  • Introduce Azure Key Vault for production

Prerequisites

Concept deep-dive

Source priority (later wins)

  1. appsettings.json
  2. appsettings.{Environment}.json
  3. User Secrets (Development only)
  4. Environment variables
  5. Command-line args
  6. Azure Key Vault (if configured)
// appsettings.json
{
  "ShopNest": {
    "Payment": { "Provider": "Razorpay", "TimeoutSeconds": 30 },
    "FeatureFlags": { "NewCheckout": false }
  }
}
public class PaymentOptions
{
    public const string Section = "ShopNest:Payment";
    public string Provider { get; set; } = "";
    public int TimeoutSeconds { get; set; }
}

builder.Services.Configure<PaymentOptions>(
    builder.Configuration.GetSection(PaymentOptions.Section));

public class CheckoutController : Controller
{
    private readonly PaymentOptions _payment;
    public CheckoutController(IOptionsSnapshot<PaymentOptions> payment)
        => _payment = payment.Value;
}
InterfaceWhen
IOptions<T>Singleton snapshot at startup
IOptionsSnapshot<T>Per request, reloads when file changes
IOptionsMonitor<T>Singleton with change callbacks

User Secrets: dotnet user-secrets set "ShopNest:Payment:ApiKey" "rzp_test_xxx"

Hands-on — ShopNest Multi-Environment Deployment

  1. Add appsettings.Staging.json with different DB connection.
  2. Bind PaymentOptions and FeatureFlags classes.
  3. Toggle NewCheckout flag in checkout view.
  4. Document Key Vault setup for production (no keys in repo).

Common errors & best practices

  • Committing appsettings.Production.json with secrets — use env vars / Key Vault.
  • IOptions in Singleton expecting reload — use IOptionsMonitor.
  • ASPNETCORE_ENVIRONMENT not set on server — wrong config file loaded.

Interview questions

Q: IOptions vs Snapshot vs Monitor?
A: Snapshot per request with reload; Monitor singleton with OnChange events.

Q: User Secrets purpose?
A: Local dev secrets outside project tree — never committed.

Q: Env var naming?
A: Double underscore for nesting: ShopNest__Payment__ApiKey.

Summary

  • Configuration merges multiple sources with defined priority
  • Options pattern gives typed, testable settings
  • User Secrets + Key Vault keep payment keys out of Git
  • Feature flags enable safe rollout per environment

Previous: Middleware
Next: Filters in ASP.NET Core

FAQ

Can I hot-reload appsettings?

IOptionsMonitor/ Snapshot pick up file changes when reloadOnChange is true.

Where set ASPNETCORE_ENVIRONMENT?

launchSettings.json locally; App Service Configuration in Azure.

Interview Q&A for this course

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ASP.NET Core Complete Tutorial (ShopNest)

On this page

Introduction After this article you will Prerequisites Concept deep-dive Source priority (later wins) Hands-on — ShopNest Multi-Environment Deployment Common errors &amp; best practices Interview questions Summary FAQ Can I hot-reload appsettings? Where set ASPNETCORE_ENVIRONMENT?
Module 1: Foundations
What is ASP.NET Core? Complete Guide Setting Up ASP.NET Core Development Environment ASP.NET Core Project Structure Explained MVC Architecture in ASP.NET Core — Complete Guide Controllers and Actions in ASP.NET Core Routing in ASP.NET Core — Conventional and Attribute Routing Views and Razor Syntax in ASP.NET Core Layouts, Partial Views and View Components Models and ViewModels in ASP.NET Core Forms, Model Binding and Validation in ASP.NET Core Tag Helpers in ASP.NET Core — Complete Guide Static Files, Bundling and Minification in ASP.NET Core
Module 2: Entity Framework Core
Entity Framework Core — Introduction and Setup EF Core Code First — Models, Migrations, Database EF Core CRUD Operations — Create, Read, Update, Delete EF Core LINQ Queries — Beginner to Advanced EF Core Relationships — One-to-One, One-to-Many, Many-to-Many EF Core Fluent API — Advanced Configuration EF Core Repository Pattern and Unit of Work EF Core Performance Optimization Database First Approach with EF Core (Scaffold) EF Core with SQL Server — Advanced Features
Module 3: Dependency Injection & Middleware
Dependency Injection in ASP.NET Core — Complete Guide Middleware in ASP.NET Core — Complete Guide Configuration in ASP.NET Core — appsettings, Environment Variables, Secrets Filters in ASP.NET Core — Action, Authorization, Exception, Resource, Result Logging in ASP.NET Core — ILogger, Serilog, NLog Error Handling and Exception Management in ASP.NET Core
Module 4: Authentication & Security
ASP.NET Core Identity — Complete Setup Guide Authentication in ASP.NET Core — Cookie and JWT Authorization in ASP.NET Core — Roles, Policies, Claims JWT Authentication with Refresh Tokens — Complete Implementation OAuth2 and External Login (Google, Facebook, Microsoft) Data Protection and Encryption in ASP.NET Core HTTPS, SSL Certificates and Security Best Practices
Module 5: Web API
Building REST APIs with ASP.NET Core — Complete Guide API Versioning in ASP.NET Core Swagger / OpenAPI Documentation in ASP.NET Core Input Validation in Web APIs — FluentValidation and Data Annotations Pagination, Filtering and Sorting in ASP.NET Core APIs HTTP Client and Consuming External APIs in ASP.NET Core Minimal APIs in ASP.NET Core .NET 8 SignalR — Real-Time Web Applications
Module 6: Advanced Architecture
Clean Architecture in ASP.NET Core CQRS Pattern with MediatR in ASP.NET Core Repository Pattern — Deep Dive with Generic Repository Background Services and Hosted Services in ASP.NET Core Caching in ASP.NET Core — In-Memory, Distributed, Redis Health Checks in ASP.NET Core AutoMapper in ASP.NET Core Microservices with ASP.NET Core — Introduction Message Queues with RabbitMQ / Azure Service Bus in ASP.NET Core gRPC with ASP.NET Core
Module 7: Testing
Unit Testing ASP.NET Core with xUnit and Moq Integration Testing in ASP.NET Core Testing EF Core — In-Memory vs SQLite Performance Testing and Load Testing ASP.NET Core APIs Test-Driven Development (TDD) in ASP.NET Core
Module 8: Deployment & DevOps
Deploying ASP.NET Core to IIS on Windows Server Docker and Containerization for ASP.NET Core Deploying ASP.NET Core to Azure App Service CI/CD with GitHub Actions for ASP.NET Core Azure SQL Database with ASP.NET Core Environment Configuration and Secrets Management
Module 9: Real-World Projects
Build a Complete Blog Website with ASP.NET Core MVC Build an E-Commerce Product Catalog API (ASP.NET Core Web API) Build a Student Management System (Complete CRUD App) Build a Job Portal (Full Stack ASP.NET Core) Build a REST API with Clean Architecture — Complete Guide Build a Real-Time Chat App with SignalR and ASP.NET Core
Module 10: Advanced Topics
Blazor WebAssembly and Blazor Server — Complete Guide gRPC, GraphQL and Alternative API Styles in ASP.NET Core Rate Limiting and API Throttling in ASP.NET Core .NET 8 Output Caching in ASP.NET Core .NET 8 ASP.NET Core .NET 9 New Features — Complete Guide