Links

• https://github.com/milanm/DotNet-Developer-Roadmap

Courses

• Architecture Interview Questions & Answers: https://questpond.teachable.com/courses/2748052/lectures/60198323

🗓️ 14-Week .NET Backend Developer Prep Plan

Phase 1 – Core Foundations (Weeks 1–4)

Week 1 – C# & OOP Fundamentals

• OOP: Inheritance, Abstraction, Polymorphism, Encapsulation - OOPS Concepts

• Classes vs Structs vs Records - CSharp Primer

• Async/Await, Task Parallel Library (TPL), Cancellation Tokens

• LINQ & Collections (IEnumerable, IQueryable, deferred execution)
  📚 [C# Docs](https://learn.microsoft.
  /en-us/dotnet/csharp/)

• Dometrain - Deep Dive C#

Week 2 – SOLID Principles & Design Patterns (Creational/Structural)

• SOLID principles with C# examples

• Creational: Singleton, Factory, Abstract Factory, Builder

• Structural: Adapter, Decorator, Composite, Proxy
  📚 Design Patterns in C# – Refactoring.Guru

Week 3 – ASP.NET Core Basics

• Middleware & Request Pipeline

• Controllers, Routing, Filters

• Options pattern, Configuration

• Dependency Injection basics (Scoped, Transient, Singleton)
  📚 ASP.NET Core Docs

Week 4 – SQL & EF Core

• SQL fundamentals (indexes, joins, transactions)

• EF Core basics: DbContext, migrations, queries

• EF Core performance: tracking vs no-tracking, compiled queries
  📚 EF Core Docs

Phase 2 – Advanced Patterns & Architecture (Weeks 5–8)

Week 5 – Design Patterns (Behavioral)

• Strategy, Observer, Mediator, Command, Chain of Responsibility

• Real-world usage in .NET
  📚 Refactoring.Guru – C# Patterns

Week 6 – Dependency Injection & Modular Design

• Built-in DI container deep dive

• Scoped vs Transient vs Singleton

• Modular architecture with DI, Composition Root
  📚 MS Docs – Dependency Injection

Week 7 – Domain Driven Design (DDD)

• Entities, Value Objects, Aggregates

• Repositories & Services

• Domain Events
  📚 MS Learn – DDD Guide

Week 8 – Event Sourcing & CQRS

• Event Sourcing basics, Event Store

• CQRS with MediatR in .NET

• Demo project (Order Management)
  📚 CQRS Pattern – MS Docs

Phase 3 – System-Level & Senior Prep (Weeks 9–14)

Week 9 – Advanced ASP.NET Core

• Authentication: JWT, Identity, OAuth2, OpenID Connect, Azure AD/MSAL

• Authorization policies

• Caching: In-memory, Distributed, Redis
  📚 ASP.NET Security Docs

Week 10 – Observability & Performance

• Logging: Serilog, structured logs

• Tracing: OpenTelemetry, Application Insights

• Profiling: BenchmarkDotNet, dotTrace

• EF Core performance tuning (async queries, connection pooling)
  📚 OpenTelemetry for .NET

Week 11 – .NET Aspire

• Aspire AppHost & AppModel

• Telemetry, health checks, configuration management

• Cloud-ready setup for microservices
  📚 MS Docs – .NET Aspire

Week 12 – Clean Architecture & Microservices

• Clean Architecture, Onion, Hexagonal

• API Gateway, REST, gRPC

• Messaging: MassTransit, NServiceBus, Azure Service Bus/Event Grid

• Azure basics: App Service, Storage, SQL DB
  📚 MS Docs – .NET Architecture

Week 13 – Testing & Interview Prep

• Unit testing: xUnit, FluentAssertions, Moq

• Integration Testing with TestServer

• System design practice (scaling APIs, event-driven systems)

• LeetCode practice (C# filter)
  📚 Testing in .NET

Week 14 – Capstone & Mock Interviews

• Build a small end-to-end backend project using:

  • DDD + EF Core + CQRS + Aspire

  • Authentication, caching, logging

• Final review of all topics

• Mock interviews (system design + coding)
  📚 Try .NET

🎯 Capstone Project: Event-Driven Order Management System

🔑 Objective

Build a backend system where customers can place orders, payments are processed, and inventory is updated — using DDD, EF Core, CQRS, Event Sourcing, .NET Aspire, and Clean Architecture.

🏗️ Architecture Overview

• Presentation Layer

  • ASP.NET Core Web API (minimal APIs or controllers)

  • Authentication (JWT or Azure AD/MSAL)

  • Swagger for API docs

• Application Layer

  • CQRS with MediatR (separate commands and queries)

  • Input validation (FluentValidation)

• Domain Layer (DDD)

  • Entities: Order, Product, Customer, Payment

  • Value Objects: Money, Address

  • Aggregates: OrderAggregate with OrderItems

  • Domain Events: OrderPlaced, PaymentProcessed, InventoryUpdated

• Infrastructure Layer

  • EF Core with SQL Server

  • Event Store (can simulate with EF table or use EventStoreDB if ambitious)

  • Repository pattern

  • Dependency Injection setup

• Integration (Event-Driven)

  • Publish/subscribe with MassTransit + RabbitMQ (or Azure Service Bus)

  • Event Sourcing: Keep track of order events for replay

  • Outbox pattern (optional for reliability)

• .NET Aspire Integration

  • Use Aspire’s AppHost to orchestrate services (API + DB + Messaging)

  • Centralized telemetry and health checks

  • Configuration management with Aspire

• Observability

  • Logging with Serilog (structured logs)

  • Tracing with OpenTelemetry

  • Metrics dashboards (Prometheus/Grafana or App Insights)

⚡ Core Features to Implement

1. Order Service

   • Create new order (with validation, aggregates, domain events)

   • Update/cancel order

   • Query order status (CQRS read model)

2. Payment Service

   • Process payment for an order

   • Publish PaymentProcessed event

3. Inventory Service

   • Listen to OrderPlaced event → reduce stock

   • Publish InventoryUpdated event

4. Event Sourcing

   • Store all order events (OrderPlaced, OrderShipped, etc.)

   • Ability to replay events to rebuild state

5. Observability

   • Track request latency, failed payments, stock levels via logs/metrics

🧪 Extra Stretch Goals

• Add a gRPC endpoint for inter-service communication

• Deploy to Azure App Service or Docker Compose with Aspire AppHost

• Add Integration Tests with TestServer

📚 Resources for Capstone

• MS Docs – Clean Architecture in .NET

• MediatR CQRS Sample

• .NET Aspire

• MassTransit with RabbitMQ

✅ By completing this, you’ll demonstrate mastery of:

• C# fundamentals + OOP

• SOLID + Design Patterns

• ASP.NET Core + EF Core

• DDD + CQRS + Event Sourcing

• Microservices & Messaging

• Observability + Cloud readiness with Aspire