Open Source Slack-Alternative Chat App

Here are open-source Slack alternatives chat app that already available to beat Slack by providing great features that slack doesn’t yet have.



Multi-Platform Web Chat Server, developed in JavaScript, using the Meteor fullstack framework. Code is 100% Open Source

It is a great solution for communities and companies wanting to privately host their own chat service or for developers looking forward to build and evolve their own chat platforms.

It is featuring video conference, helpdesk chat, file sharing, link previews, voice messages, API to Integrate your chat to multiple services: GitHub, GitLab, JIRA, Confluence and others, media embedding, file uploading, screensharing, and more

There are native applications for Windows, Mac, and Linux, and mobile client applications for iOS and Android.

URl :
License : MIT License



Friends use of peer-to-peer (P2P) technology in theires chat app. Message authentication currently relies on GitHub but could be modified to use a decentralized alternative such as Blockchain Auth.

URl :
License : MIT License



An open source, self-hosted Slack-alternative to proprietary SaaS messaging, It’s brings all your team communication into one place, making it searchable and accessible anywhere.

Mattermost written in Golang and React and runs as a production-ready Linux binary under an MIT license with either MySQL or Postgres.

URl :
License : MIT License

Let’s Chat


An Self-hosted chat app for small teams built by the company Security Compass . It’s one of the most popular open-source Slack alternatives on GitHub with over 7K stars and 960 forks.

Technology behind this chat, in the backend is pure use Javascript (NodeJS), MongoDB for storage and in the frontend appears to use Backbone.

Features include group chat, direct messaging, and private channels. It’s also has a Sandstorm app, making it easier for non-technical users to host their own Let’s Chat server.

URl :
License : MIT License


Zulip is a powerful open source group chat that written in Python (Twisted + Django). in the frontend, it’s use JavaScript + jQuery and from the backend use
PostgreSQL, Memcached, Redis, RabbitMQ

Features include group and direct messaging, private groups, threaded conversations, in-line media previews, email and desktop notifications, and tons of integrations.

In addition to working in the browser, Zulip also has native desktop and mobile applications for iOS, Android, Linux, Mac, and Windows so you can chat on almost any platform.

URl :
License : Apache License