Phalcon is a modern PHP framework with the typical feature set you’d expect. Database ORM, error handling, MVC architecture, and plenty of other features are available, but what makes Phalcon unique is how it is packaged.
Instead of being plain PHP files, which get compiled and executed for every request by the PHP interpreter, Phalcon is written in C and is exposed to PHP as an extension.Since the framework is already compiled (in the extension), there is no framework PHP code that gets loaded. This makes Phalcon immensely faster than any other PHP framework. Other frameworks require multiple files to be loaded and executed before even touching any of your app-specific code, which can tank performance on busy sites.
Even as a PHP extension, Phalcon only is invoked when called by your PHP application, keeping your PHP interpreter compatible with other non-Phalcon applications with no performance penalty.
However this is a trade-off, Phalcon requires root access to your server to install the extension and can potentially be a “black box” in your application, where it is much harder to go through the internals of the framework.
Based on what I’ve been reading, Phalcon seems very capable and I am excited to dive deeper into the Phalcon ecosystem in the next few days. If you are interested in learning more, I recommend the official Phalcon website.