Btwinus is described as 'Anonymous, end-to-end encrypted two-person chat that runs in the browser and starts from a shareable link. The WebRTC handshake is encrypted inside the link; messages then go directly between browsers. No account, no app, no server in the message path. Open source' and is a Encrypted Chat app in the security & privacy category. There are more than 10 alternatives to Btwinus, not only websites but also apps for a variety of platforms, including Android, Mac, Windows and Linux apps. The best Btwinus alternative is Signal, which is both free and Open Source. Other great sites and apps similar to Btwinus are Telegram, SimpleX Chat, Wire and Briar.