Hydrus

Hydrus is a name used in various contexts, but in contemporary digital software it most commonly refers to Hydrus Network, an open‑source application for organizing and managing large collections of digital media, especially images and videos. Hydrus Network is designed to help users catalog media with a strong emphasis on tagging, searchability, and offline privacy.

The core concept is a flexible tagging system that lets users assign multiple descriptors to individual files, enabling complex queries, filters, and discovery within large catalogs. Users can import media from local folders, downloads, and other sources, and the software supports automated tagging and metadata assignment as content is added. This automation helps maintain consistent organization across large collections.

Hydrus Network generally uses a client–server architecture, where a central repository can be accessed by one or more client interfaces. This model supports coordinated curation and, in practical setups, allows users to run a private server for personal or small-group use while keeping data under local control.

The project is maintained by an independent developer with input from a community of contributors and is released under an open-source license. It is available on major desktop platforms, including Windows, macOS, and Linux. Hydrus Network is recognized for its privacy‑friendly, local‑first design and its emphasis on scalable organization to accommodate growing media libraries.