Kometa is an open-source Python application that manages and automates metadata for Plex media libraries. It can build collections and playlists, apply overlays, and keep customizations reproducible by defining everything in external configuration files.

Key Features

Automated metadata updates for Plex items (artwork, titles, summaries, and more)
Automatic creation and maintenance of collections and playlists
Overlay generation and application for posters (for example, badges and labels)
Integrations with third-party metadata sources such as TMDb, Trakt, and IMDb
Optional automation integrations with Sonarr and Radarr to support library growth
Reproducible, portable configuration that can be reapplied after server/database loss or migrations

Use Cases

Curate Plex libraries with automated collections (genres, decades, studios, streaming services)
Standardize and reapply custom poster overlays and metadata across multiple Plex servers
Keep a large media library organized and visually consistent with minimal manual effort

Limitations and Considerations

Primarily designed for Plex; it is not a general-purpose media server
Requires initial configuration and ongoing maintenance of YAML-based config/definition files

Kometa is best suited for Plex users who want fine-grained, repeatable control over library presentation and organization. It combines metadata sources and automation rules to keep collections, overlays, and library metadata consistent over time.