Hydra vs Palace

Hydra is a continuous integration service for projects based on Nix. It checks out project source periodically or continuously, builds it, runs tests, and produces reports. Work is organized into jobsets whose inputs can trigger builds when they change; jobsets can also depend on one another. Flake jobsets are supported when their outputs expose a hydraJobs attribute set. Jobs can produce packages, ISO images, or tarballs, and jobset inputs can use Git checkout sources. Hydra also provides a JSON API. It is aimed at Nix and NixOS package developers, not people who only need to use NixOS. Hydra is open source under GPL-3.0 and listed at free. It is self-hosted, with no hosted option listed, and running it is currently supported only on NixOS; the repository recommends the NixOS module for production. Flake evaluation is restricted from accessing files outside the Nix store. Some state is stored in the database, so backups are needed, and the wiki reports that hydra-queue-runner can sometimes leave queued builds unscheduled.

Palace is a personal media manager and wallpaper engine for organizing and displaying wallpapers and other media. You can sort items into categories, albums, and favorites, then search by name or tag. Display choices include fill, fit, center, tile, stretch, or spanning multiple monitors, with adjustable background colors and effects. Automatic rotation can run sequentially or in shuffle mode, at intervals from five seconds to several hours, and can target individual displays. Palace supports GIFs, video files such as MP4 and WebM, GLSL shaders, and locally stored images; desktop video wallpapers require MPV. Online sources use public JSON files and must provide direct public media URLs, not private or password-protected files. Local media works offline, and ordinary use does not require an account. Palace says wallpapers, preferences, and settings stay on the device and personal images are not uploaded or accessed. The web hub supports browsing community sources, downloading wallpapers, and submitting source URLs. A Palace lifetime license costs $4 as a one-time purchase; Google Play costs $7.99, paid once for Android only.