Authy

Authy provides strong authentication for the connected world, protecting people and the enterprise against malicious attacks. Our two-factor authentication (2FA) security solution enables organizations to minimize risk while enhancing the user experience. Authy 2FA provides a fast-to-implement, highly scalable and proven 99.999 % reliable alternative to passwords. Used by 11,000+ websites serving 2 million consumers worldwide, it's designed to give users  the ability to self-service or easily manage their own 2FA experience. Coinbase, CloudFlare, Humble Bundle and Twitch.tv are just some Authy clients.  

Source: https://www.linkedin.com/company/authy/about/