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].




The best alternative to Slack is Conversations, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Slack and many of them are so hopefully you can find a suitable replacement. Other interesting alternatives to Slack are Mirotalk, Nextcloud Talk, Dino and Twake.
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].




Powered by WebRTC, Real-time video call, chat room and screen sharing entirely browser based.



Self-hosted communication platform with secure audio, video, chat, web conferencing, screensharing, advanced encryption, and metadata privacy, running on user-controlled servers, supporting web and mobile apps, and eliminating third-party data exposure.




Dino is a modern open-source chat client for the desktop. It focuses on providing a clean and reliable Jabber/XMPP experience while having your privacy in mind. Using GTK+/Vala.



Same user-friendliness of Slack, but running on the decentralized/federated XMPP network. No longer give your private/confidential data to a third-party.
Most users think Dino is a great Slack alternative.
Twake is a real-time teamwork platform. It is a suite of collaborative tools that includes the specificities of some bestsellers (Slack, Trello, Google Drive...). We provide professional messaging, storage space, online collaborative editors (Words, Excel, PowerPoint), task...




I like Twake as an alternative to Slack because it is open-source.

Almost everyone thinks Twake is a great Slack alternative.
All you need in a team collaboration tool dedicated to small efficient teams. Chat, notes, drive, online collaborative edition, calendars, news, spaces, notifications...
eXo Platform is an all-in-one digital workplace solution that helps you connect, align and engage your teams around a single interface. You can use it to improve company and peer-to-peer communication, boost collaboration and manage company knowledge.








Zenchat combines messaging and task management, letting users turn messages into tasks for streamlined collaboration. It supports task-related and topic-based chats while integrating with the Zenkit Suite. Features include SSO, SCIM provisioning, and audio/video messaging, with free and paid plans available.




Stackfield is a Slack-alternative for chat, collaboration, calendaring and file-sharing. It enables encrypted chatting (end-to-end encryption) and is hosted in Germany.




One of the best Slack alternatives. It's more private due to being hosted in Germany (and therefore under German law), and even more so because unlike Slack it offers end-to-end encrypted messaging, which means what you say to your colleagues cannot be intercepted by the host company or given away to the NSA.

Fleep is a messenger for your teams and projects. It enables communication within and across organizations - be it your team chats, project communication or 1:1 conversations.




Allows communicating also with email in addition to in team shared content.

Almost everyone thinks Fleep is a great Slack alternative.
Collaboration app for teams of all sizes. Hubgets makes team knowledge instantly available through chat, voice and video. Fast results, fewer interruptions, more transparency, stronger teamwork.




A cool tool, with sound and video integrated. Simple, colorful interface, makes me happy using it.

Nextcloud Talk, like most of Nextcloud, is very heavyweight. So if you don't have a very good server, it's going to be very slow (for me it was around 10 seconds to send a single message)