Open source alternatives to Slack

2 free, self-hostable tools you can use instead of Slack, sorted by GitHub stars.

Alternatives to Slack 2

Buzz

Replaces Slack

Run team chat, code review, and automation in Buzz, a self-hosted open source workspace from Block where AI agents join as first-class members.

★ 36,200 Apache-2.0 CRM & Project Management

dcts-shipping

Replaces Slack

Host a self-hosted Discord-style chat server with end-to-end encrypted DMs, voice chat, and screensharing. AGPL-3.0, with Android and desktop clients.

★ 645 AGPL-3.0 CRM & Project Management