Credential Engine developed the Credential Transparency Description Language (CTDL) to ensure that data related to credentials and skills speak a common language. The CTDL is a schema (a type of mini-language that people and systems can use to understand each other even if their data comes from different sources and that anyone can use to share information about credentialing data. The CTDL provides a common and unified way of describing information in the Credential Registry, and also an open language that can be used on the Web.