Extbase - Building Better Extensions
What is Extbase?
Extbase is a framework for TYPO3 extension development. It was introduced with TYPO 4.3 in 2009 and is destined to entirely replace the classic way of writing TYPO3 CMS extensions (pibase). Most importantly it is a gateway for TYPO3 4.x/6.x to Neos as it is a backport of TYPO3 Flow technology, the framework upon which Neos is based.
Why should I use Extbase?
If you develop an extension for TYPO3 you should most definitely use Extbase. The days of piBased extensions are numbered. Extbase gives you the benefit of a modern, clear and highly structured way of PHP development with a hidden bonus: If you know Extbase, getting into Flow will be much, much easier for you. Another bonus: Porting Extbase extensions to Neos will be a walk in the park, whereas porting a piBased extension to Neos will be incredibly laborious if possible at all, and probably a very bad experience for everyone involved.
How do I start?
Have a look at the Official Manual, get a comprehensive introduction with the book Developing TYPO3 CMS Extensions with Extbase and Fluid or have some Cheat Sheets at hand for your reference.