Classoos is an online textbook service for primary and secondary schools. The company's catalog features digital textbooks from all leading publishers and follows GCSE, IGCSE, National 4 and 5, AS and A-Level/(Advanced) Higher, Edexcel, OCR, AQ-A, IB, and more shared OER content. Applying interactive layers to content, Classoos is available on tablets, desktops, smartphones, and the web.