Recurly - Subscription billing and recurring billing management. Recurly offers enterprise-class subscription billing for thousands of companies worldwide.
TypingDNA Authenticator - 2FA codes in your browser, secured by the way you type
Pabbly Subscriptions - Pabbly Subscription is a recurring billing & subscription management software.
PropelAuth - PropelAuth hosts and manages your authentication.
Reepay - Reepay takes care of your subscriptions so you can focus on your core business.
Authorizer - Authorizer is an open-source authentication and authorization solution for your applications.