OkHttp

OkHttp is an open-source HTTP client library for Java and Android, originally developed by Square and now maintained by the open-source community. It provides a fast, efficient HTTP client designed for modern networks and mobile devices. OkHttp supports HTTP/2 and connection pooling, which reduces latency by sharing a single connection for multiple requests. It also includes transparent GZIP compression and response caching to reduce data usage and improve performance.

The library centers on a small API surface with core classes such as OkHttpClient, Request, Response, and Call. Requests can be executed synchronously via execute() or asynchronously via enqueue(Callback). OkHttp’s interceptor mechanism allows monitoring, rewriting requests and responses, and implementing features such as retry logic, authentication, or logging. The client supports WebSocket connections and is capable of retries and timeouts to handle transient network failures gracefully.

OkHttp is widely used as the networking layer in Android apps and in server-side Java projects, and it is commonly paired with Retrofit as a higher-level HTTP client. It adheres to modern web standards, including RFC-compliant caching and support for HTTP/2 multiplexing. The project is released under the Apache License 2.0.