Portal:Free and open-source software
Free and open-source software (FOSS) is software available under a license that gives users the right to use, share, modify, and distribute the software – modified or not – to everyone and provides the means to exercise those rights using the software's source code. FOSS is an inclusive umbrella term encompassing free software and open-source software. The rights guaranteed by FOSS originate from the "Four Essential Freedoms" of The Free Software Definition and the criteria of The Open Source Definition. All FOSS has publicly available source code, but not all source-available software is FOSS. FOSS is the opposite of proprietary software, which is licensed restrictively or has undisclosed source code.
The historical precursor to FOSS was the hobbyist and academic public domain software ecosystem of the 1960s to 1980s. Free and open-source operating systems such as Linux distributions and descendants of BSD are widely used, powering millions of servers, desktops, smartphones, and other devices. Free-software licenses and open-source licenses have been adopted by many software packages. Reasons for using FOSS include decreased software costs, increased security against malware, stability, privacy, opportunities for educational usage, and giving users more control over their own hardware.
The free software movement and the open-source software movement are online social movements behind widespread production, adoption and promotion of FOSS, with the former preferring to use the equivalent term free/libre and open-source software. FOSS is supported by a loosely associated movement of multiple organizations, foundations, communities and individuals who share basic philosophical perspectives and collaborate practically, but may diverge in detail questions. (More about free and open-source software...)
Alternative terms for free software, such as OSS, FOSS, and FLOSS, have been a recurring issue among free and open-source software users from the late 1990s onwards. These terms share almost identical licence criteria and development practices.
In 1983 Richard Stallman launched the free software movement and founded the Free Software Foundation to promote the movement and to publish its own definition. Others have published alternative definitions of free software, notably the Debian Free Software Guidelines. In 1998, Bruce Perens and Eric S. Raymond began a campaign to market open-source software and founded the Open Source Initiative, which espoused different goals and a different philosophy from Stallman's. (Full article...)
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- Android (operating system) – Operating system for mobile devices (130,995 views, B rating, Top importance)
- Bitcoin – Decentralized digital cryptocurrency (130,309 views, B rating, Low importance)
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- Firefox – Web browser made by Mozilla (109,883 views, B rating, Top importance)
- Truth Social – American alt-tech social media platform (103,422 views, B rating, Low importance)
- ... that Terry Davis created TempleOS, a Bible-themed operating system that had more than 120,000 lines of code? (2025-03-20)
- ... that the browser extension AdNauseam blocks and clicks on advertisements at the same time? (2025-01-06)
- ... that Riley Testut developed AltStore because he wanted to publish his emulator Delta? (2024-06-01)
- ... that you can keep a snowflake in a browser tab? (2022-11-08)
- ... that Kotaku revised an article about Nintendo Switch emulation after Nintendo complained that the previous version encouraged piracy? (2022-10-17)
- ... that Vegeta is used to attack HTTP-based applications? (2022-09-11)
- ... that Leafpad is a text editor for Linux that is comparable to Notepad for Windows? (2022-08-30)
Transcluding 7 of 24 total
Wikipedia is an encyclopedia written entirely by volunteers. If you wish to contribute to our articles, feel free to join the free and open-source task force. To find a place to start, you can expand a stub or improve existing articles. To pick an existing article, you could choose from the list of most-viewed FOSS articles or a vital article about free and open-source software. The vital articles are listed below with their current content assessment rating:
Android (operating system)
Tim Berners-Lee
Copyright
Donald Knuth
Linux
Open-source software
Patent
Linus Torvalds
Bell Labs
Berkeley Open Infrastructure for Network Computing
Bitcoin
Copyleft
Debian
Digital rights management
Brendan Eich
Emacs
Ext4
Firefox
Free content
Free-culture movement
Free Software Foundation
GIMP
GNU Project
GitHub
GTK
Leslie Lamport
Lawrence Lessig
LibreOffice
Lua
Yukihiro Matsumoto
Bram Moolenaar
MySQL
Ogg
Open source
OpenGL
PHP
Perl
Python (programming language)
R (programming language)
Guido van Rossum
Ruby (programming language)
SPICE
Richard Stallman
Swift (programming language)
TeX
Tor (network)
VLC media player
Vim (text editor)
VirtualBox
Wine (software)
X Window System

- Impediments and challenges
- Digital Millennium Copyright Act · Digital rights management · Tivoization · Software patents and free software · Trusted Computing · Proprietary software · SCO-Linux controversies · Binary blobs
- Adoption issues
- OpenDocument format · Vendor lock-in · GLX · Free standards · Free software adoption cases
- About licences
- Free software licences · Copyleft · List of FSF-approved software licenses
- Common licences
- GNU General Public License · GNU Lesser General Public License · GNU Affero General Public License · IBM Public License · Mozilla Public License · Permissive free software licences
- History
- ...of free software · Free software movement · Timeline of free and open-source software
- Groupings of software
- Comparison of free software for audio · List of open-source video games
- Naming issues
- GNU/Linux naming controversy · Alternative terms for free software · Naming conflict between Debian and Mozilla
The following Wikimedia Foundation sister projects provide more on this subject:
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Commons
Free media repository -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikiversity
Free learning tools -
Wiktionary
Dictionary and thesaurus
Types of software

The following types are the selected sub-categories of Category:Free software:
- Antivirus software
- Application servers
- Astronomy software
- Audio software
- Backup software
- BitTorrent clients
- Business software
- Compilers and interpreters
- Computer-aided design software
- Content management systems
- Cross-platform software
- Data compression software
- Database management systems
- Desktop environments
- Development toolkits and libraries
- Educational software
- Email software
- File managers
- File transfer software
- Games
- GIS software
- 2D graphics software
- 3D graphics software
- Groupware
- HTML editors
- Image galleries
- Instant messengers
- Internet forum software
- IRC clients
- Learning support software
- Mathematics software
- Media players
- Multimedia codecs, containers, and splitters
- Network management software
- Note-taking software
- Office suites
- Operating systems
- Optical disc authoring software
- PDF software
- Personal information managers
- Project management software
- Science software
- Search engine software
- Special purpose file systems
- Spreadsheets
- System software
- Television software
- TeX software
- Text editors
- Usenet clients
- Version control software
- Video software
- VoIP software
- Web browsers
- Windowing systems
- Word processors
- X window managers
People, projects, and groupings
- Apache Software Foundation projects
- Free software programmers
- Free and open-source software organizations
- Members of the Free Software Foundation board of directors
- Free Software Foundation
- GNU project and GNU project software
- Free software companies
Non-software materials
- Free and open-source software licenses
- Free software websites
- Free-software awards
- Free-software events
- Copyleft
- Free software culture and documents
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