Open Source Projects in PHP
Friendica
Decentralized social network platform
Elgg
Open-source social networking engine and framework
Question2Answer
Q&A community platform
Unmark
Bookmark manager and to-do app
TestLink
Test and requirements management
SimplePie
PHP library for parsing RSS and Atom feeds
Kohana
HMVC PHP framework focused on security and lightness
WinterCMS
Laravel-based CMS focused on simplicity
FuelPHP
Flexible HMVC PHP framework
Bludit
Simple flat-file CMS for blogs and sites
Handesk
Laravel helpdesk and lead management app
MODX
Flexible PHP content framework with total template freedom
HTMLy
Databaseless flat-file blogging platform in PHP
Sulu
The PHP content management system for developers.
Postfix Admin
Web interface for managing Postfix mail servers
Open Source Social Network
PHP social networking software with a modular component system
Faveo Helpdesk
Laravel-based ticketing system
MyBB
Community forum software built by volunteers
Flyimg
On-the-fly image resizing and optimization microservice
TYPO3
Enterprise-level CMS with an extensive extension system
Fork
User-friendly CMS for beginners and pros
ProcessWire
Developer-friendly CMS with a jQuery-like API
OrangeHRM
HR management software trusted by millions to run people operations without licensing fees
pH7Builder
Self-hosted builder for dating and social community sites