What are microservices, and what specific tools does the .NET ecosystem provide to build and run them?

Microservices structure an application as a collection of small, independently deployable services, each owning a specific capability (payments, orders, auth), communicating over the network rather than in-process -- this improves scalability and fault isolation compared to a single monolith, at the cost of added networking, deployment, and observability complexity. .NET supports this architecture through ASP.NET Core for building lightweight service APIs, Docker for packaging each service consistently, Kubernetes for orchestration (scaling, service discovery, self-healing), gRPC for efficient inter-service communication, message brokers (RabbitMQ, Azure Service Bus, Kafka) for event-driven communication, and .NET Aspire for higher-level tooling around service discovery, configuration, and observability across the whole distributed system.

[ApiController]
[Route("api/products")]
public class ProductsController : ControllerBase {
    [HttpGet]
    public IEnumerable<string> Get() => new[] { "Product1", "Product2" };
}
// Each microservice like this is packaged into its own Docker image and
// deployed/scaled independently behind Kubernetes