AppStream

Infrastructure for distro-agnostic software-centers and universal software component metadata

AppStream is a collaborative effort for enhancing the way we interact with the software repositories provided by the distribution by standardizing sets of additional metadata.

AppStream provides the foundation to build software-center applications. It additionally provides specifications for things like a unified software metadata database, screenshot services and various other things needed to create user-friendly application-centers for software distributions.

You can find a C/GLib based reference implementation of the full specification at github.com/ximion/appstream (https://github.com/ximion/appstream) and report bugs about the implementation as well as the specification itself at the issue tracker (https://github.com/ximion/appstream/issues). The project also provides a web form for the simple creation of metainfo XML files for upstream maintainers at freedesktop.org/software/appstream/metainfocreator (https://www.freedesktop.org/software/appstream/metainfocreator/#/).

Authors: Matthias Klumpp, Michael Vogt, Richard Hughes, and Vincent Untz

Publication Date: 2026-01-28

1 About AppStream

1.1 What is AppStream?

2 Upstream Metadata

2.1 Generic Component
2.2 Release Information
2.3 Desktop Applications
2.4 Console Applications
2.5 Web Applications
2.6 Services
2.7 Addons
2.8 Fonts
2.9 Icon Themes
2.10 Codecs
2.11 Input Methods
2.12 Firmware
2.13 Driver
2.14 Localization
2.15 Repositories
2.16 Operating System
2.17 Runtime

3 Catalog Metadata

3.1 AppStream Catalog XML
3.2 AppStream Catalog YAML
3.3 Icon Cache

4 Miscellaneous

4.1 Version Comparison Algorithm
4.2 URI Handler

5 Metadata Quickstart

5.1 For GUI application upstream maintainers
5.2 For upstream projects providing addons
5.3 For distributors packaging Appstream metadata
5.4 Translating Metadata

6 Data Validation

6.1 Validator Issues

7 Manual pages

appstreamcli — Handle AppStream metadata formats and query AppStream data
appstreamcli compose — Compose AppStream metadata catalog from directory trees

8 AppStream API Reference

Index

Copyright © 2012-2024 Matthias Klumpp. This documentation is dual-licensed under the GNU Free Documentation License (GFDL), v1.3 (https://www.gnu.org/licenses/fdl.txt) with no invariant sections or later or the CC Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) license (SPDX: CC-BY-SA-4.0 OR GFDL-1.3-or-later).