Sitefinity CMS provides you with the tools and means for quick and easy construction of attractive and functional web sites. You can use a variety of built-in components, such as Pages, Modules, and Widgets and perform tasks through the API, instead of the user interface.
For tips how to make sure the startup process of your application after customizations is optimized, see Optimize development.
Apart from using the Sitefinity CMS built-in functionality, you can also develop custom functionality for your website. Sitefinity CMS extensible software architecture and design enable you to extend the functionality of almost any widget or module. You can do this by either adding your own new functionality, through modifying of existing functionality, or by integrating with third-party applications.
Custom development with Sitefinity CMS
Create a custom widget
You can use control definitions to build structured declarative user interfaces and reuse components when building the backend UI. Thus, you also enable third-party developers to plug their own components to extend that UI.
Last, but not least, you can leverage Sitefinity CMS ASP.NET MVC technology in its classic, pure, and hybrid modes. The mode you use depends on your development process, as well as the functionality you want to implement.