Stratum is described as '(formerly Authenticator Pro) is a community-backed open-source project which aims to provide privacy and security to users. The source-code is auditable by anyone on GitHub and released under the GPL 3.0 license' 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 Bitwarden, which is both free and Open Source. Other great apps like Stratum are KeePass, Aegis Authenticator, Proton Authenticator and Ente Auth.