uPort is described as 'A self-sovereign identity and user-centric data platform: the keys to the digital world you've always wanted' and is an app in the Bitcoin & Cryptocurrency category. There are three alternatives to uPort for a variety of platforms, including Linux, Mac, Windows, Online / Web-based and BSD. The best alternative is NameCoin, which is both free and Open Source. Other great apps like uPort are Scuttlebot (Free, Open Source) and OneName (Free).
A peer-to-peer log store Sharing on a secure peer-to-peer network Scuttlebot is an open source peer-to-peer log store used as a database, identity provider, and messaging system. It features global replication, file-syncronization, and end-to-end encryption.