As modern software architecture increasingly embraces microservices, performance and simplicity become vital.
Enter Minimal APIs in .NET 8—a powerful evolution in ASP.NET Core that enables developers to build high-performance, lightweight microservices with less boilerplate and faster startup times.
Whether you’re an enterprise scaling services or a startup validating ideas quickly, Minimal APIs offer the agility and performance needed for today’s software systems.
Why Use Minimal APIs in .NET 8 for Microservices?
Traditional ASP.NET Core MVC comes with rich architectural patterns, but it often includes unnecessary overhead for small, focused services. Minimal APIs in .NET 8 strip away the layers—controllers, annotations, and extensive routing rules—resulting in:
- Rapid bootstrapping and improved performance
- Lower memory usage
- Fewer files and less ceremony
- Ideal compatibility with Docker, Kubernetes, and serverless
For microservices that serve targeted responsibilities, Minimal APIs provide the flexibility and speed that larger frameworks may lack.
Getting Started: Building a Microservice with Minimal APIs
Let’s walk through building a simple catalog microservice using Minimal APIs in .NET 8.
Step 1: Create a New Project
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dotnet new web -n CatalogService
cd CatalogService
This scaffolds a clean web project without controllers or views.
Step 2: Add a Simple Endpoint
Edit Program.cs:
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var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.MapGet(“/”, () => “Catalog Service is running!”);
app.Run();
Then run the app:
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dotnet run
And just like that, you have a running web API with a few lines of code.
Creating CRUD Endpoints with Minimal APIs in .NET 8
Let’s add basic product management (CRUD operations) for a product catalog.
Model Definition
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record Product(int Id, string Name, decimal Price);
In-Memory Product Store
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var products = new List<Product>
{
new Product(1, “Laptop”, 1099.99m),
new Product(2, “Keyboard”, 59.99m)
};
Register CRUD Endpoints
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app.MapGet(“/products”, () => products);
app.MapGet(“/products/{id}”, (int id) =>
{
var product = products.FirstOrDefault(p => p.Id == id);
return product is not null ? Results.Ok(product) : Results.NotFound();
});
app.MapPost(“/products”, (Product product) =>
{
products.Add(product);
return Results.Created($”/products/{product.Id}”, product);
});
app.MapPut(“/products/{id}”, (int id, Product updatedProduct) =>
{
var index = products.FindIndex(p => p.Id == id);
if (index == -1) return Results.NotFound();
products[index] = updatedProduct with { Id = id };
return Results.Ok(updatedProduct);
});
app.MapDelete(“/products/{id}”, (int id) =>
{
var product = products.FirstOrDefault(p => p.Id == id);
if (product is null) return Results.NotFound();
products.Remove(product);
return Results.Ok();
});
This setup gives you a working microservice using Minimal APIs in ASP.NET Core—without controllers, services, or added layers.
Dependency Injection in Minimal APIs
Even with its simplicity, Minimal APIs in .NET 8 still support essential architectural practices like dependency injection.
Create a Service Interface and Implementation
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public interface IProductService
{
IEnumerable<Product> GetAll();
}
public class ProductService : IProductService
{
public IEnumerable<Product> GetAll() => new[]
{
new Product(1, “Monitor”, 199.99m),
new Product(2, “Mouse”, 29.99m)
};
}
Register and Inject the Service
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builder.Services.AddSingleton<IProductService, ProductService>();
app.MapGet(“/di-products”, (IProductService service) =>
{
return Results.Ok(service.GetAll());
});
This keeps business logic modular and testable while preserving the minimalistic structure.
Securing Minimal APIs in .NET 8
Authentication and authorization are fully supported in the Minimal API model:
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app.UseAuthentication();
app.UseAuthorization();
app.MapGet(“/secure-data”, [Authorize] () => “Secret Data”)
.RequireAuthorization();
You can also apply role-based access, policies, and JWT authentication—just like in traditional ASP.NET Core apps.
Generating API Documentation with Swagger
Documenting your API is simple with OpenAPI (Swagger) integration:
Install Swagger
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dotnet add package Swashbuckle.AspNetCore
Configure Swagger in Program.cs
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builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
Swagger supports Minimal APIs with full parameter and response metadata, ideal for public-facing or internal APIs.
Deploying .NET 8 Minimal APIs in Microservices Architecture
These APIs are perfect for:
- Serverless functions (e.g., Azure Functions, AWS Lambda)
- Dockerized services in CI/CD pipelines
- Kubernetes pods managed via Helm or Kustomize
- Lightweight APIs behind API Gateways
Example Dockerfile
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FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
WORKDIR /app
FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
WORKDIR /src
COPY . .
RUN dotnet publish -c Release -o /app/publish
FROM base AS final
COPY –from=build /app/publish .
ENTRYPOINT [“dotnet”, “CatalogService.dll”]
When Not to Use Minimal APIs
While powerful, Minimal APIs in .NET 8 aren’t ideal for every use case. You might prefer MVC if:
- Your team is heavily invested in layered architecture
- The application requires advanced routing, filters, or model binding
- You’re building a large-scale system with many developers
Best Practices for Minimal APIs
- Use route groups to organize endpoints
- Avoid complex business logic in lambdas; delegate to services
- Use record types or DTOs for clarity and immutability
- Monitor performance for memory usage and cold-start behavior
- Always document using Swagger for API visibility
Conclusion
Minimal APIs in .NET 8 offer a modern, clean, and highly efficient way to build microservices. They’re not just for beginners or quick prototypes—they’re production-ready, enterprise-friendly, and cloud-optimized.
For startups aiming to ship fast, or enterprises scaling microservice-based platforms, Minimal APIs provide the flexibility and performance required in today’s fast-paced development environment.
If you haven’t explored building microservices with Minimal APIs in .NET 8, now is the perfect time to start. The simplicity may surprise you—and the scalability will keep you going.
Additional Resources: