MELPA

MELPA (Emacs Lisp Package Archive) is a community‑maintained repository of Emacs packages. It provides a centralized, convenient way to discover, install, and update Emacs Lisp packages from within the editor. MELPA hosts thousands of packages contributed by volunteers and distributes prebuilt elisp files and byte‑compiled versions to simplify installation.

Origin and scope: MELPA was created to streamline the distribution of user‑contributed Emacs packages beyond traditional tarballs. Packages are stored by project maintainers in separate source repositories, and a build system fetches the sources, builds them, and publishes a ready‑to‑install package on melpa.org. The service aims to keep packages up to date with minimal user intervention and to support rapid release cycles.

Structure: MELPA offers three repositories with different guarantees. MELPA provides the latest commits on the package’s default branch, delivering rolling updates. MELPA Stable releases are based on tagged versions, suitable for reproducible installations. MELPA Unstable contains experimental builds that may be less tested and more prone to issues.

Usage: To use MELPA from Emacs, add the repository to your package manager, for example by including the MELPA entry in your package archives and then refreshing contents. After that, you can install packages with the built‑in package manager (for example, via M‑x package‑install). Some packages from MELPA may require external system dependencies or additional configuration.

Build and maintenance: Packages are created by individual maintainers and described with a recipe; the build system compiles and packages them for distribution. The archive is hosted at melpa.org and maintained by volunteers, with updates delivered according to the chosen repository (stable, main, or unstable).