IHttpClientFactory

IHttpClientFactory is a factory abstraction that creates HttpClient instances configured through the Microsoft.Extensions.Http package. It centralizes HttpClient lifetimes and the lifetimes of HttpMessageHandler instances, helping to prevent socket exhaustion and issues from improper handler reuse by pooling handlers across clients.

Registration and configuration are done in the dependency injection container. Typical patterns include adding the factory itself with services.AddHttpClient(), or configuring named clients with services.AddHttpClient("Backend", cfg => { cfg.BaseAddress = new Uri("https://api.example.com/"); }). You can also configure default headers, timeouts, and other settings in one place.

Clients can be created in code by requesting an HttpClient from the factory: var client = httpClientFactory.CreateClient("Backend"); This approach provides a consistently configured HttpClient without leaking handler lifetimes. A common alternative is to use typed clients by registering a class that accepts HttpClient in its constructor, for example services.AddHttpClient<MyServiceClient>(cfg => cfg.BaseAddress = new Uri("https://api.example.com/")); The typed client can then be injected wherever needed.

Benefits of IHttpClientFactory include improved reliability and performance through proper handler lifetime management, simplified configuration and reuse of common settings, and easier integration with resilience policies such as retries and circuit breakers via Polly. It also supports both named and typed client patterns, enabling central configuration while preserving the flexibility to tailor individual clients.

In summary, IHttpClientFactory provides a robust way to create and manage HttpClient instances in modern .NET applications, improving resource usage, configurability, and resilience across HTTP communications.