Cowboy is a small, fast, and modern HTTP server for Erlang/OTP.
Cowboy addresses the need for a complete HTTP stack within a minimal codebase by optimizing for low latency and low memory usage through the use of binary strings. The server provides routing capabilities that selectively dispatch requests to handlers written in Erlang, and it leverages Ranch for connection management, allowing it to be embedded within other applications. The implementation emphasizes clean, well-tested Erlang code and supports HTTP/2, HTTP/3, WebSocket, and WebTransport protocols.
Cowboy suits developers building high-performance web services in Erlang/OTP environments where resource efficiency and low latency are priorities. It is particularly appropriate for applications requiring embedded HTTP server functionality or those needing to handle multiple concurrent connections with minimal overhead. The project is positioned as production-ready and includes comprehensive documentation available both online and offline, along with example code to guide implementation.
The project maintains active engagement through a Discord server and issues tracker for community support, with commercial support available. Documentation is extensive, including user guides in PDF and HTML formats, function reference man pages, and full Asciidoc sources. The codebase includes examples demonstrating various use cases, and the project provides mechanisms for offline documentation generation and installation.
