AppStream is a collaborative effort for making machine-readable software metadata easily available to programs that need it. It is part of the Freedesktop ecosystem and provides a convenient way to retrieve information about available software, making it one of the building blocks for modern software centers.

AppStream consists of a specification to describe individual software component metadata in XML (so-called MetaInfo files), as well as a derived specification for a metadata-collection format to provide a list of these metadata entries in XML or YAML for easy consumption by software centers and other tools which need to know about available software in a repository. In addition to the metadata specification, AppStream specifies a set of related features to help providing better metadata for software repositories (primarily in Linux distributions). This reference implementation of AppStream provides a shared library to work with these metadata files, features to index and query their data quickly, as well as other useful related functionality to make building programs which work with software metadata very easy.

This repository contains:

• the AppStream specification
• the appstreamcli utility to access and edit metadata, manipulate caches, show diagnostic information, etc. (see man appstreamcli)
• a GLib/GObject based library for reading and writing AppStream metadata in XML and YAML, accessing the system data pool, and auxiliary functionality
• a Qt6 based library for accessing AppStream

• AppStream Documentation - The AppStream specification and help
• Releases - All (signed) releases of AppStream
• AppStream on Freedesktop - The original Freedesktop.org page

For help and development discussion, check out the AppStream mailinglist.

If you are an upstream application author and want to add a MetaInfo file to your application, check out the Quickstart Guides in the documentation. An even quicker way to get to your metadata is using the MetaInfo Creator web application. You can check out its source code here.

If you are a (Linux) distributor or owner of a software repository you want to generate AppStream Collection Metadata for, you may want to take a look at the AppStream Generator project.

• Meson (>= 0.62)
• glib2 (>= 2.58)
• GObject-Introspection
• libxml2
• libyaml
• libcurl (>= 7.62)
• libxmlb (>= 0.3.6)

• Vala Compiler (vapigen) (for Vala VAPI file)
• Snowball (for stemming support)

• Qt6 Core

• DAPS

If you are using the released tarballs, the HTML documentation will be prebuilt and DAPS, which is a heavy dependency, is not required to make it available locally. Of course, AppStream doesn't need the documentation to function, so it can even be built completely without it.

To compile AppStream, make sure that you have all required libraries (development files!) installed. Then continue (the build system will complain about missing dependencies).

Use Meson to configure AppStream and build it with ninja:

mkdir build
cd build
meson setup <flags> ..
ninja
ninja test

Possible AppStream-specific flags are:
-Dqt=true -- Build the Qt interface library (default: false)
-Dvapi=true -- Build Vala API to use the library with the Vala programming language (default: false)
-Dcompose=true -- Build libappstream-compose library and appstreamcli compose tool for composing metadata indices (default: false)
-Dapt-support=true -- Enable integration with the APT package manager on Debian (default: false)
-Ddocs=true -- Build specification and other documentation, requires DAPS (default: false)
-Dinstall-docs=true -- Install documentation (default: true)
-Dmaintainer=true -- Enable strict compiler options - use this if you write a patch for AppStream (default: false)
-Dstemming=true -- Enable support for stemming in fulltext searches (default: true)

To install the compiled binaries and required data, execute ninja install with superuser permission.

You can help translating AppStream via Weblate. Check out the AppStream Weblate Page.