Authy is a free two-factor authentication (2FA) app that focuses on security for online activities such as banking, buying bitcoin, Tweeting, or streaming on Twitch. The app is free because it's paid for by businesses working with Twilio to ensure users stay protected. These businesses pay for authentications generated by Twilio’s pre-built authentication software, the Authy API. The app offers benefits like multi-device convenience, encrypted backups in the cloud, and easy recovery.