๐Ÿ’ฌ

Communication & Chat

Replaces: WhatsApp, Slack, Teams

Encrypted and privacy-friendly messengers and chat platforms. Secure alternatives to WhatsApp, Slack and Microsoft Teams.

๐Ÿ›ก๏ธ 18 Open Source Tools

Element/Matrix

Decentralized messenger with end-to-end encryption based on Matrix

11.5k
โ†ณ WhatsApp Slack +1
Apache-2.0 โ—โ— Medium
May 2026
Signal

Signal

The gold standard for secure private communication

14.5k
โ†ณ WhatsApp Slack +1
AGPL-3.0 โ— Easy
May 2026

XMPP/Prosody

Open messaging protocol with the lightweight Prosody server

1.2k
โ†ณ WhatsApp Slack +1
MIT โ—โ—โ— Advanced
Feb 2026

Rocket.Chat

Versatile team communication platform with extensive integrations

41.0k
โ†ณ WhatsApp Slack +1
MIT โ—โ— Medium
May 2026
Mattermost

Mattermost

Secure Slack alternative for enterprises and DevOps teams

31.0k
โ†ณ WhatsApp Slack +1
MIT / AGPL-3.0 โ—โ— Medium
May 2026
Zulip

Zulip

Team chat with a unique threading model for productive communication

22.0k
โ†ณ WhatsApp Slack +1
Apache-2.0 โ— Easy
May 2026

Jami

Decentralized peer-to-peer messenger without central servers

1.1k
โ†ณ WhatsApp Slack +1
GPL-3.0 โ— Easy
Apr 2024

Briar

Secure messenger for activists and journalists with Tor support

3.2k
โ†ณ WhatsApp Slack +1
GPL-3.0 โ— Easy
Mar 2026

Colanode

And local-first Slack and Notion alternative that puts you in control of your data

4.6k
โ†ณ WhatsApp Slack +1
Apache-2.0 โ—โ— Medium
Apr 2026

Sharkord

Lightweight, self-hosted, open-source chat server with voice, video, text, and screen sharing.

1.0k
โ†ณ WhatsApp Slack +1
MIT โ— Easy
May 2026

Ethora

Engine for chat ๐Ÿ’ฌ, AI assistants ๐Ÿค– & wallets ๐Ÿชช.

521
โ†ณ WhatsApp Slack +1
AGPL-3.0 โ—โ— Medium
May 2026

Server

screen sharing for developers https://screego.net/

10.4k
โ†ณ WhatsApp Slack +1
GPL-3.0 โ—โ— Medium
May 2026

Spacebarchat

Spacebar is a free open source selfhostable discord compatible communication platform

6.7k
โ†ณ WhatsApp Slack +1
AGPL-3.0 โ—โ— Medium
Apr 2026

Bark Server

Backend of Bark

3.4k
โ†ณ WhatsApp Slack +1
MIT โ—โ— Medium
May 2026

Rocket.chat.electron

The Secure CommsOSโ„ข for mission-critical operations

1.7k
โ†ณ WhatsApp Slack +1
MIT โ—โ— Medium
May 2026

Databag

fast & lightweight self-hosted messenger

1.5k
โ†ณ WhatsApp Slack +1
Apache-2.0 โ— Easy
Apr 2026

Toxic

A Tox-based instant messaging and video chat client.

1.3k
โ†ณ WhatsApp Slack +1
GPL-3.0 โ—โ— Medium
Feb 2026

Watomatic

Auto reply app to enable auto reply for messengers like WhatsApp and Facebook Messenger

538
โ†ณ WhatsApp Slack +1
GPL-3.0 โ—โ— Medium
May 2026