# Open-source alternatives to Slack

> Slack: A team messaging platform with channels, threads and integrations. The best self-hosted, open-source alternatives are Mattermost, Rocket.Chat and Zulip. All of them can run on your own server, so your data stays under your control. All 6 apps here are open source.

## Key facts

| Fact | Value |
|---|---|
| Commercial product | Slack |
| Category | Team Chat |
| Alternatives listed | 6 |
| Top pick | Mattermost (39,271 stars, AGPL-3.0) |
| Canonical URL | https://appsgit.com/alternatives/slack |

## Alternatives, in recommended order

- [Mattermost](https://appsgit.com/apps/mattermost): Platform for secure collaboration across the entire software development lifecycle, can be integrated with Gitlab (alternative to Slack). (39,271 stars, AGPL-3.0, TypeScript, Docker)
- [Rocket.Chat](https://appsgit.com/apps/rocket-chat): Communications platform that puts data protection first (alternative to Gitter.im and Slack). (46,213 stars, MIT, TypeScript, Docker)
- [Zulip](https://appsgit.com/apps/zulip): Zulip is a powerful, open source group chat application. (25,998 stars, Apache-2.0, Python)
- [Element](https://appsgit.com/apps/element): Fully-featured Matrix client for Web, iOS & Android. (13,542 stars, AGPL-3.0, TypeScript)
- [Synapse](https://appsgit.com/apps/synapse): Server for Matrix, an open standard for decentralized persistent communication. (4,681 stars, AGPL-3.0, Python)
- [Stoat](https://appsgit.com/apps/stoat): Stoat is a user-first chat platform built with modern web technologies. (2,665 stars, AGPL-3.0, JavaScript, Docker)

## Comparisons

- [Mattermost vs Rocket.Chat](https://appsgit.com/compare/mattermost-vs-rocket-chat)
- [Rocket.Chat vs Zulip](https://appsgit.com/compare/rocket-chat-vs-zulip)
- [Mattermost vs Zulip](https://appsgit.com/compare/mattermost-vs-zulip)

More in this category: [Team Chat](https://appsgit.com/categories/team-chat)

---

Canonical page: https://appsgit.com/alternatives/slack
Source: appsgit (https://appsgit.com), the app store for github. Data from the GitHub API, refreshed nightly.
Machine access: JSON API https://appsgit.com/api/v1/apps (OpenAPI: https://appsgit.com/openapi.json), MCP server https://mcp.appsgit.com/mcp, full index https://appsgit.com/llms-full.txt.