SongRec is a Linux desktop application (with CLI counterpart) that recognizes songs by sending audio fingerprints to Shazam's proprietary API. It is written in Rust and uses GTK4/libadwaita for the GUI. The architecture is a multi-threaded monolith with dedicated threads for microphone capture, audio processing (fingerprinting), HTTP communication with Shazam, and the GUI event loop. External dependencies include Shazam's servers (reverse-engineered endpoint), FFmpeg for audio file decoding, and platform audio backends (CPAL, PulseAudio, ALSA). The application provides persistent song history with CSV export, favorites, MPRIS integration, system tray icon, and configurable request intervals to handle rate limiting. The codebase shows good engineering practices with trait abstractions for audio backends, a typed channel message system, and versioned preferences. A separate Python reference implementation exists in the `python-version/` directory but is not the primary codebase.