Open Source Viber Alternatives

Signal is a messaging app with an unexpected focus on privacy, combined with all the features expected from a modern IM app. Signal has received a lot of praise from all around the world for its security and privacy-respecting technologies.

Element is a secure collaboration and messaging app based on the Matrix protocol. It’s decentralised to deliver digital sovereignty, and based on an open standard for easy connections and interoperability. It is end-to-end encrypted by default.

With the rise of widespread government monitoring programs, Tox is an easy to use application that allows you to connect with friends and loved ones without anyone else listening in.

Wire is the most secure collaboration platform featuring messenger, voice, video, conference calls, file-sharing, and external collaboration –all protected by the most secure end-to-end-encryption.

Mattermost is a secure, open source platform for communication, collaboration, and workflow orchestration across tools and teams.

Zulip is a group chat app in which messages are threaded by topic, helping you have long-running, organized conversations.

Conversations is a privacy focused, open source XMPP Texting [Jabber] client for Android 4.0+ smart phones with wife-approved easy encryption [OTR, OMEMO, or GPG].

Nextcloud Talk is a fully self-hosted audio/video and chat communication service. It features web and mobile apps and is designed to offer the highest degree of security while being easy to use.

An alternative Telegram client based on TDLib, with higher speed, slicker animations and experimental features.

Open source Jabber (XMPP) client with multi-account support, clean and simple interface. Being both free (as in freedom!) and ad-free, Xabber is designed to be the best Jabber client for Android .