httpclient-factory

To prevent socket exhaustion in .NET 10, use IHttpClientFactory to manage HttpClient lifetimes rather than instantiating them per-request. This standardizes client creation and eliminates unsafe instantiation patterns that cause socket depletion.

You configure retries and circuit breakers for outbound HTTP calls by registering clients with AddHttpClient and attaching AddStandardResilienceHandler(). This applies consistent resilience policies to every outbound request, with options to disable retries for unsafe HTTP methods.

Named and keyed clients in IHttpClientFactory provide clear configuration and correct lifetime management for distinct external APIs. .NET 10 introduces keyed client registration, allowing precise selection and management of multiple differently-configured HTTP clients within your application.

Yes, you can use a DelegatingHandler pipeline to centralize cross-cutting concerns like auth token injection and correlation ID propagation in .NET HTTP clients. This handler-pipeline pattern keeps your core services clean and separates external HTTP behavior from business logic.

You unit test HTTP clients using IHttpClientFactory by implementing mock HttpMessageHandler patterns. This provides deterministic responses for integration and unit tests, allowing you to validate outbound HTTP behavior without making actual network calls.

You should disable retry policies for unsafe HTTP methods like POST when using Microsoft.Extensions.Http.Resilience to prevent duplicate side effects. Configure AddStandardResilienceHandler selectively to ensure retries only apply to safe, idempotent outbound operations.