HTTPClients

An HTTP client is a software component that initiates HTTP requests to servers and processes the responses. It abstracts the network protocol details and provides a convenient API for performing common operations such as retrieving resources, submitting data, and following redirects. HTTP clients typically support setting request methods, headers, query parameters, body content, and cookies, and they handle serialization and deserialization of data to and from formats such as JSON or XML.

Key features include connection pooling to reuse TCP/TLS connections, timeouts, automatic redirects, cookie management, authentication mechanisms, and error handling. They may offer streaming capabilities for large payloads, support for compressed responses, and built-in retry policies. Many clients support asynchronous or non-blocking I/O to improve throughput in concurrent applications.

Protocol support: Most modern HTTP clients target HTTP/1.1 by default but increasingly provide support for HTTP/2, which enables multiplexing of multiple requests over a single connection, and HTTP/3, which uses QUIC for improved latency and resilience.

Usage patterns: HTTP clients are commonly used by applications to communicate with RESTful services, microservices, and external APIs, as well as for testing, scraping, or performing health checks. They may include higher-level abstractions for JSON serialization, form encoding, and streaming data.

Examples by ecosystem: In Python, libraries include requests and httpx; in Java, Apache HttpClient and OkHttp; in .NET, HttpClient; in JavaScript, fetch API and axios. The choice depends on language, performance requirements, and feature needs.