A web-based application development platform for building web-based applications. It resides within the Oracle database and comes included with Oracle Database. Many people agree that APEX is the best development platform for building database-centric web-based applications. (See next question for more on this.) For a great, free video introduction to APEX, see https://www.youtube.com/embed/wkGKQrQPO60 SkillBuilders’ Oracle APEX Training on YouTube.