Let's Encrypt - Let’s Encrypt is a free, automated, and open certificate authority brought to you by the Internet Security Research Group (ISRG).
LoginTC - Simply Strong Two-Factor Authentication LoginTC is best in class. Effortless Administration. Intuitive User Experience. Cost-effective solution for all organizations.
JSON Web Token - JSON Web Tokens are an open, industry standard RFC 7519 method for representing claims securely between two parties.
DIGIPASS - DIGIPASS offers two-factor authentication solutions for mobile applications.
Amazon Cognito - Amazon Cognito lets you add user sign-up, sign-in, and access control to your web and mobile apps quickly and easily. It scales to millions of users and supports sign-in with social identity providers and enterprise identity providers via SAML 2.0.
Authy - Best rated Two-Factor Authentication smartphone app for consumers, simplest 2fa Rest API for developers and a strong authentication platform for the enterprise.