While it is quite easy to implement support for U2F by using a server library, it is sometimes desirable to keep the U2F related logic outside of your application, making as few modifications as possible to the application itself. For this reason we have developed a U2F server, accompanied by a REST style API that we call U2FVAL. The server provides U2F registration, authentication, storage of registration data, and provides the client with metadata about the devices used. This enables existing applications to enable multi-device U2F support without needing to modify any existing database tables.

To get started with U2FVAL, check out our standalone server, and the REST API. We also provide a number of connector libraries, which make using the REST API even easier. You will find them here.