CodeIgniter

PHP (version 4 or 5) framework with a thin model layer. Includes an ActiveRecord class for database agnostic (mostly) data retrieval. Good community support in its forums. Further development available via GitHub: https://github .

Free Open Source Mac OS X Windows Linux Self-Hosted

Symfony

Symfony is a set of reusable PHP components and a PHP framework for web projects.

Free Open Source Mac OS X Windows Linux Web PHP

Agile Toolkit

Agile Toolkit is a PHP framework for developing Web User Interfaces. Inspired by desktop GUI it provides a full object-oriented foundation for Business and Presentation logic of your web software.

Free Open Source Mac OS X Windows Linux Web

Zend Framework

Extending the art & spirit of PHP, Zend Framework is based on simplicity, object-oriented best practices, corporate friendly licensing, and a rigorously tested agile codebase.

Free Open Source Mac OS X Windows Linux Web

FuelPHP

Fuel is a simple, flexible, community driven PHP 5.3 web framework based on the best ideas of other frameworks with a fresh start and a design pattern in HMVC. The...

Free Open Source Mac OS X Windows Linux Web

Silex PHP micro-framework

Silex - The PHP micro-framework based on Symfony2 Components Silex is a PHP microframework for PHP 5.3. It is built on the shoulders of Symfony2 and Pimple and also...

Free Open Source Mac OS X Windows Linux

phunction

Small and carefully designed PHP 5.2+ HMVC framework.

Free Open Source Mac OS X Windows Linux Web

bitcore

A pure and powerful JavaScript Bitcoin library or blockchain library.

Free Open Source Windows Linux Mac JavaScript

TomP2P

A P2P-based high performance key-value pair storage library.

Free Open Source Mac OS X Windows Linux