Week 1–2: Minimal APIs Basics

Goal

Build a Books API with in-memory storage. Learn how Minimal APIs work, how to create endpoints, and how to test them with Swagger.

Essential (70% of time)

Core skills:

• Create a Minimal API project with dotnet new web
• Make GET and POST endpoints
• Use route parameters (/books/{id})
• Return proper status codes using the Results helper
• Test with Swagger UI

Key resources

• Minimal APIs Overview
• Tutorial — Build a Minimal API
• Microsoft Learn Path
• Swagger in ASP.NET Core

LLM prompts

“Show me how to create a .NET 8 Minimal API with a GET endpoint that returns a list of books. Books have Id, Title, Author, Year. Use an in-memory List.”

“Add POST, PUT, DELETE endpoints for books. Use Results.Ok(), Results.Created(), Results.NotFound() for proper status codes.”

“Explain when to use Results.Ok() vs Results.Created() vs Results.NotFound(). Simple examples please.”

Brief (20% of time)

• Understanding Program.cs structure
• Query parameters (?search=value)

Optional (skip if needed)

• .http files for testing
• Dependency injection details

Practical project

Build a Books API with in-memory storage using a List<Book>.

Learning activities

1. Run dotnet new web -n BooksApi and explore the generated files
2. Add a Book class with Id, Title, Author, Year
3. Create GET /books — returns all books
4. Create GET /books/{id} — returns one book or 404
5. Create POST /books — adds to list, returns 201
6. Create PUT /books/{id} — updates book, returns 204 or 404
7. Create DELETE /books/{id} — removes book, returns 204 or 404
8. Open Swagger and manually test every endpoint

Key concepts to master

• app.MapGet(), app.MapPost(), app.MapPut(), app.MapDelete() syntax
• Route parameters vs query parameters
• Results.Ok(), Results.Created(), Results.NotFound(), Results.BadRequest()
• Running and testing locally with Swagger

Deliverable

Books API with in-memory List, all CRUD endpoints working in Swagger.

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