TYPO3 is a powerful and mature content management system containing many features and a large degree of flexibility.
Extbase is a PHP-based framework which supports developers in creating clean and easily maintainable TYPO3 extensions. The template engine Fluid makes sure that the user interface of the extension can easily be created individually.
Extbase ensures a clear separation between different concerns, which makes maintenance a lot more simple thanks to modular code. Because of this modular design, the development time and associated costs are reduced for initial development and for adjustments. Extbase also lessens the burden on the developer when it comes to security-relevant and repetitive tasks: for example the validation of arguments, the persistence of data, and access to TypoScript and FlexForm settings. Developers can therefore focus on solving the problems of their clients much more efficiently.
Using Extbase needs a basic understanding of concepts like domain driven design, whilst planning and modeling the extension thoroughly before implementation. In return, the source code of the extension becomes a lot more readable, more flexible and more extensible.