iMessage is an instant messaging service.

Bitmessage is a decentralized, encrypted, peer-to-peer, trustless communications protocol that can be used by one person to send encrypted messages to another…

Blink is the best real-time communications client using the SIP protocol.

Coccinella is a free and open-source cross-platform client for the XMPP/Jabber-instant messaging-protocol.

Dialog Messenger is a handy and feature-rich enterprise multi-device messenger available for server or cloud.

ICQ is an open source instant messaging software.

Bit Chat is a secure, peer-to-peer, open source instant messenger with end-to-end encryption.

BlackBerry Messenger, also known as BBM is an instant messenger and videotelephony application included on BlackBerry devices that allows messaging and voice …

ChatSecure is a messaging application for iOS which allows OTR and OMEMO encryption for the XMPP protocol.

Conversations is an open source XMPP/Jabber client for the Android platform.

Google Duo is a video chat mobile app available on the Android and iOS operating systems.

Imo free video calls and chat is a kind of Communication apps for Android.