rTorrent is a high-performance BitTorrent client designed for headless (daemon) or ncurses-based terminal use. Its architecture is a monolithic event-driven application with clearly separated subsystems: core download management (libtorrent binding), display abstraction (ncurses windows and stubs), input handling, an extensive RPC layer supporting XMLRPC, JSONRPC, and SCGI, session persistence with async write-back, and a Lua scripting engine. The system exposes hundreds of commands for controlling torrents, trackers, peers, throttles, and DHT. Remote administration is a first-class feature, and the terminal UI is fully customizable via configuration. The codebase is mature and professionally structured, with strong test coverage and well-defined modular boundaries, though it carries some legacy dependencies (autotools, vendored TinyXML2, CppUnit) and deprecated command aliases.