Refit

Refit is an open-source library for the .NET platform that enables type-safe consumption of RESTful web services by defining an interface whose methods map to API endpoints. Inspired by Retrofit for Android, Refit generates a concrete implementation at runtime from an annotated interface, streamlining HTTP communication and JSON (or other) serialization.

In practice, developers declare an interface with methods annotated by HTTP verbs and routes. Parameters are mapped to path segments, query parameters, or request bodies. At runtime, Refit creates an implementation (via a factory such as RestService.For<T>(httpClient)) that executes HTTP requests and deserializes responses into the declared return types, typically using asynchronous Task-based methods. JSON is the default data format, with options to customize the serializer and HttpClient behavior.

Key features include type-safe API clients, attribute-driven routing, support for headers and various parameter bindings, cancellation support, and integration with common .NET serialization libraries. The approach reduces boilerplate compared with manual HttpClient usage and promotes a declarative style for API definitions.

History and usage: Refit was developed as an open-source project by members of the .NET community and has been widely adopted in .NET projects to simplify REST API consumption. It supports .NET Standard and contemporary .NET runtimes, and works with serializers such as Newtonsoft.Json or System.Text.Json.

See also: Retrofit, RestSharp, HttpClient.

References and documentation are available through the project’s repository and official documentation, which detail installation via NuGet, interface design patterns, and integration tips for common .NET application types.