List of free and open-source web applications
All web applications, both traditional and Web 2.0, are operated by software running somewhere. This is a list of free software which can be used to run alternative web applications. Also listed are similar proprietary web applications that users may be familiar with. Most of this software is server-side software, often running on a web server.
| Application | Service | License | Requirements | Similar proprietary web application |
| Gallery | Photo sharing | GNU GPLv3 | MySQL | flickr, Picasa |
| Piwigo | Photo sharing | GNU GPL | MySQL + PHP | flickr, Picasa |
| OpenBroadcaster | Video streaming | GNU AGPLv3+ | MySQL | YouTube |
| Plumi | Video streaming | ZPL | YouTube | |
| PeerTube | Video streaming | GNU AGPLv3+ | YouTube | |
| Libre.fm | Music streaming | GNU AGPLv3+ | PostgreSQL or MySQL | last.fm |
| CiteSeerX | Bibliographic database | Apache | MySQL or PostgreSQL | SpringerLink |
| OpenStreetMap | Mapping | ODbL | MySQL or PostgreSQL | Google Maps |
| ownCloud | File sharing, web calendar, etc. | GNU AGPLv3 | Dropbox, drop.io | |
| Nextcloud | File sharing, File synchronization, web calendar, etc. | GNU AGPLv3+ | Dropbox, box | |
| Seafile | File sharing | GNU GPLv2 | Dropbox, drop.io | |
| Tahoe Least-Authority File Store | File sharing | GNU GPLv2+ | Dropbox, drop.io | |
| iFolder | File sharing | GNU GPLv2+ | Dropbox, drop.io | |
| AbiCollab | Online file editing | GNU GPLv2 | MySQL or PostgreSQL | Google Docs |
| Etherpad | Online file editing | Apache | MySQL or PostgreSQL | Google Docs |
| Eucalyptus | Virtual machine provisioning | GNU GPLv3 | Amazon EC2 | |
| Globus Toolkit | Virtual machine provisioning | Various | MySQL or PostgreSQL | Amazon EC2 |
| OpenNebula | Virtual machine provisioning | Apache | SQLite3 | Amazon EC2 |
| DokuWiki | Wiki | GNU GPLv2 | Wikispaces | |
| MediaWiki | Wiki | GNU GPLv2+ | MySQL or PostgreSQL | Wikispaces |
| TiddlyWiki | Wiki | BSD license | Web browser | Evernote, Microsoft OneNote |
| Open Journal Systems | Publication management | GNU GPLv2 | MySQL or PostgreSQL | |
| WordPress | Blogging | GNU GPLv2 | MySQL | blogger.com |
| LiveJournal | Blogging | GNU GPLv2+ | blogger.com | |
| Ghost | Blogging | MIT License | JavaScript, node.js | blogger.com |
| GNU Social | Distributed social network | GNU AGPLv3 | MySQL or PostgreSQL | |
| Mastodon | Distributed social network | GNU AGPLv3 | PostgreSQL | |
| AppScale | Virtual web hosting | BSD | Google AppEngine | |
| PHPGroupware | Online office suite | GNU GPLv2 | Google Docs | |
| eGroupware | Online office suite | GNU GPLv2 | Google Docs | |
| Feng Office | Online office suite | GNU AGPL | Google Docs | |
| Roundcube | Web mail | GPLv3+ with exceptions for skins and plugins | Gmail, Hotmail | |
| IMP | Web mail | GPLv2 | IMAP server | Gmail, Hotmail |
| Squirrelmail | Web mail | GNU GPLv2 | Gmail, Hotmail | |
| Mailman | Mailing lists | GNU GPL | Google Groups, Yahoo Groups | |
| FluxBB | Forum | GNU GPLv2 | ||
| phpBB | Forum | GNU GPLv2 | ||
| MyBB | Forum | GNU LGPL | ||
| Phorum | Forum | Phorum 2.0 | ||
| Vanilla | Forum | GNU GPLv2 | ||
| Discourse | Forum | GNU GPLv2+ | ||
| EasyChair | Submission management system | |||
| LimeSurvey | Internet survey | GNU GPLv2 | SurveyMonkey, Google Form creator | |
| Cheetah News | RSS reader | GNU GPLv3 | Google Reader | |
| Tiny Tiny RSS | RSS reader | GNU GPLv3 | Google Reader | |
| pump.io | Social aggregation | Apache | FriendFeed | |
| Meneame | Social news | GNU AGPLv3 | Digg | |
| Social news | Common Public Attribution v1.0 | Digg | ||
| Mixx | Social news | Digg | ||
| Friendica | Distributed social network | MIT | ||
| Diaspora | Distributed social network | GNU AGPL | ||
| BuddyPress | Distributed social network | GNU GPL | WordPress | |
| Elgg | Distributed social network | GNU GPLv2 / MIT | ||
| Scuttle | Social bookmarking | Delicious | ||
| Connotea | Social bookmarking | Delicious | ||
| Ma.gnolia 2 | Social bookmarking | Delicious | ||
| Apertium | Translation | GNU GPLv2 | Google Translate | |
| EyeOS | Homepage | GNU AGPLv3 | iGoogle | |
| OpenCroquet | Virtual world | MIT | SecondLife | |
| OpenSimulator | Virtual world | BSD | SecondLife | |
| bitwarden | Password manager | GNU GPLv3, AGPLv3 | node.js | Dashlane, Lastpass |
| Mattermost | Web chat | MIT, AGPLv3, Apache License 2.0 | Slack |