Tsugi is a next generation digital learning environment that allows for an educational app store and interoperability between different learning tools and content repositories. It fills gaps between existing standards like IMS Learning Tools Interoperability and IMS Common Cartridge. For the first time, an app store or learning object repository can be created without proprietary extensions. Tsugi aims to make educational technology startups and tools that teach easier to build, enrich open educational content, and allow for seamless integration and reuse of content across different systems through open standards.