dotnet-core-expert_skill

Overview

This skill is a .NET 8 expert designed to help build high-performance, cloud-ready applications using minimal APIs, clean architecture, and modern C# patterns. It focuses on practical implementation: Entity Framework Core, CQRS with MediatR, JWT authentication, AOT compilation, and scalable microservice patterns. Use it as an expert pair programmer to produce production-ready projects and tests.

How this skill works

I inspect your requirements and propose a clear solution architecture with layered projects (API, Application, Domain, Infrastructure, Tests). I provide concrete code snippets and templates: minimal API endpoints, DbContext and EF Core migrations, MediatR request/handler patterns, JWT setup, DI configuration, and AOT build integration. I also recommend testing strategies (xUnit, WebApplicationFactory) and deployable artifacts (Dockerfiles, health checks, OpenAPI).

When to use it

• Starting a new .NET 8 service with minimal APIs and clean architecture
• Implementing CQRS patterns using MediatR for complex business logic
• Setting up Entity Framework Core with migrations and async repositories
• Adding JWT authentication and authorization policies to APIs
• Optimizing startup and runtime with AOT compilation for small images

Best practices

• Enable nullable reference types and use async/await for all I/O
• Keep domain models separate from API DTOs; return DTOs, not entities
• Use record types for DTOs and immutable domain objects where appropriate
• Centralize DI in the API project and avoid mixing layers’ responsibilities
• Store secrets in a secure store (Azure Key Vault, AWS Secrets Manager) and never in code
• Write integration tests with WebApplicationFactory and cover end-to-end flows

Example use cases

• Create a minimal API service with CRUD endpoints, paging, and EF Core migrations
• Implement a CQRS flow: Commands + Handlers for writes and Queries + Projections for reads using MediatR
• Add JWT-based auth with role/claim policies and refresh token handling
• Containerize a microservice, add health checks, OpenAPI docs, and Kubernetes readiness probes
• Prepare an AOT-compiled self-contained image to reduce cold-start time in serverless environments