Stratum is described as 'A free open-source two factor authentication app for Android. It features encrypted backups, icons, categories and a high level of customisation. It also has a Wear OS companion app' and is a Authenticator in the security & privacy category. There are more than 50 alternatives to Stratum for a variety of platforms, including iPhone, Android, iPad, Android Tablet and Mac apps. The best Stratum alternative is KeePass, which is both free and Open Source. Other great apps like Stratum are Aegis Authenticator, Proton Authenticator, Ente Auth and Bitwarden Authenticator.