Apostille is NEM’s built-in blockchain notary service. Unlike previous blockchain notarization services, it employs the use of dynamic notarizations that can also be modified and moved. It is a highly flexible application, providing its users with a wide array of customizable features specific to the nature of their business or application needs. Apostille container addresses allow users to govern authority over NEM namespaces, each having a unique private key. As an open source service, Apostille also allows for the development of user-specific applications to be built on top of it and interact with its features.