Magento developers primarily use PHP, a popular server-side scripting language. Magento is built on PHP and uses it extensively throughout its platform. Therefore, strong PHP skills are essential for a Magento developer. Additionally, they often work with other technologies such as JavaScript for front-end development, XML for configuration files, and MySQL for database management. Understanding CSS and HTML is also important for theme customization and design. Moreover, Magento 2 uses the Less CSS pre-processor, so knowledge of this is beneficial. For better application design and management, knowledge of PHP frameworks like Symfony, Laravel, or Zend, which include elements of MVC (Model-View-Controller) architectural patterns, is also advantageous.