Callmama - Get cheap international calling, international virtual number, Call Mama Gives an added advantage to send message and make calls to non-user of Callmama App.
Seald - Keep your conversations secure, everywhere.
CallHippo - Easy to use Phone System with World-Class Support
Crypho - End-to-end-encrypted messaging and file sharing
KrispCall - Virtual cloud phone system for business
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.