Authenticator is described as 'Simple, free, and open source two-factor authentication app. It helps keep your online accounts secure by generating unique one-time passwords, which you use in combination with your other passwords to log into supporting websites' and is a Authenticator in the security & privacy category. There are more than 50 alternatives to Authenticator for a variety of platforms, including iPhone, Android, iPad, Android Tablet and Mac apps. The best Authenticator alternative is Bitwarden, which is both free and Open Source. Other great apps like Authenticator are Aegis Authenticator, Proton Authenticator, Ente Auth and Bitwarden Authenticator.