Psst is a native desktop Spotify client written in Rust, designed as a fast, lightweight alternative to the official Electron-based client. It implements the proprietary Spotify session protocol (Shannon cipher, Diffie-Hellman key exchange, Mercury messaging) to stream audio directly, bypassing the Web API for playback. The application is structured as a workspace with three crates: `psst-core` (session management, audio pipeline, caching, Last.fm scrobbling), `psst-gui` (Druid-based GUI with controllers, widgets, and Web API integration), and `psst-cli` (simple command-line player). The GUI features a full browsing experience (home, search, library, artist/album/playlist/show details, lyrics, recommendations, credits) with async data loading via a Promise pattern and remote image caching. The audio pipeline includes decryption, decoding (symphonia), resampling, normalization, and output via cpal or cubeb. Authentication uses OAuth2 with PKCE and supports user-provided Spotify Client IDs. The project is actively developed with rolling releases and cross-platform builds (Windows, macOS, Linux).