ExpressionEngine

ExpressionEngine is an open source content management system developed by EllisLab in 2002 as a successor to pMachine Pro, a blogging system, which is written in object-oriented PHP and uses MySQL for data storage. EllisLab closed in 2018, but ExpressionEngine is still available, as an open source CMS.

With CodeIgniter, an agile, open-source framework, web professionals can use ExpressionEngine to build websites and applications. The software is meant to be useful for companies of any size and private individuals as well, and to that end it is highly customizable, and implementation may vary. Like many content management systems, various add-ons will determine what the system does, though the core features are somewhat broader than similarly classed free offerings. The Multiple Site Manager allows a user to create and manage multiple sites from a single ExpressionEngine installation. Nexcess (a partner) provides a hosting environment for an ExpressionEngine-powered website.