Just like WebGUI, Joomla is an open source content management system. As Joomla is written in PHP, which is one of Oqapi's specializations, we can build or implement websites in Joomla. Joomla also works with the MySQL-database, another of Oqapi's specializations.
So if you choose Joomla over WebGUI, Oqapi is still the right company for you!