curb is a Ruby binding to libcurl, providing a fast, full-featured HTTP client library. Named for "Curl-RuBy", it wraps libcurl's proven networking capabilities, offering support for HTTP, HTTPS, FTP, and numerous other protocols with robust connection handling. The gem provides Ruby access to libcurl's extensive feature set including connection pooling, authentication methods, and protocol options.
The library offers both easy and multi interfaces, where the easy interface handles single requests with straightforward method calls, while the multi interface enables concurrent requests for improved performance. It supports features like cookie handling, custom headers, SSL configuration, proxy support, and authentication schemes including Basic, Digest, and NTLM. curb includes support for streaming responses, upload and download progress callbacks, and connection reuse for improved efficiency. Its C extension provides performance advantages over pure Ruby HTTP clients, particularly for high-throughput scenarios.
curb excels in applications requiring high-performance HTTP operations, API clients making many concurrent requests, or systems needing libcurl's advanced protocol support and battle-tested reliability. It's particularly valuable in web scraping, API integration, file transfer applications, and monitoring systems where connection efficiency and protocol support matter. The gem's direct libcurl binding provides both performance and access to HTTP features that may not be available in higher-level Ruby HTTP libraries.