Silence – open-source SMS/MMS app compatible with multiple devices, doesn’t require internet connection.
Threema – open-source app offering E2EE, doesn’t require a phone number for account registration.
Viber – a user-friendly app with catchy interface, offers limited end-to-end encryption, supports self-destructing messages.
Apple iMessage – offers end-to-end encryption for communication between iMessage users, support self-destructing messages.
Wickr – an open-source platform with regular audits, alerts users upon taking screenshots.
Dust – offers self-deleting messaging after being read, allows unsending messages, stealth search, breach alerts.
Telegram – a bold messaging platform popular among privacy freaks for its resilience to government surveillance, optional end-to-end encryption with server-client encryption by default.
Signal – the most secure messaging app for individual users, robust end-to-end encryption by default, open-source code.