Spotify Release List is a client-side React progressive web app that lets users browse new album and single releases from the Spotify artists they follow. It authenticates directly against the Spotify Web API from the browser using OAuth 2.0 Authorization Code with PKCE (src/auth.js), then synchronizes followed artists, saved albums, saved tracks, and album metadata into local browser storage via Redux Toolkit, redux-persist and localForage. The UI presents a day-by-day release feed with dozens of filters (date range, album group, track count, favorites, duplicates, remixes, search) and supports exporting the filtered list to a new/existing Spotify playlist or a CSV file. There is no application backend; all API calls go straight to Spotify, and the app is deployable as a static site with service-worker offline support. Architecturally, the code is organized around a Redux store powered by RTK slices, redux-saga side-effect workflows, memoized reselect selectors, and persisted-state migrations. Sagas cover auth, sync, automation, CSV generation, notifications, and playlist creation; the sync pipeline fetches paginated Spotify endpoints through a bounded-concurrency worker pool and applies blocklists/filters client-side. The codebase also contains a small local data-management layer, including a binary-encoded history set and JSON Schema validation for settings. The application nature is dominant, though the local storage/offline-sync layer resembles a data pipeline in miniature. The project appears maintained and is not abandoned, but it carries moderate technical drift: it builds with Create React App 5 (an increasingly legacy toolchain) while using React 19, and it still depends on moment/react-dates. Tests are minimal (one helper test file), and typing relies on JSDoc checkJs rather than TypeScript. Overall the code is well-factored into feature-specific folders and contains several reusable redux-saga and storage patterns.