Slack: The Best Open-Source Alternatives

Slack organizes team communication in channels, threads, and direct messages. File sharing, search, and integrations with other applications complement the conversations.

The directory lists Slack in the «Team Chat» category.

Here you can find open-source alternatives, and separately marked source-available alternatives, to «Slack» (external link) in the category «Team Chat».

In the Category «Team Chat»

Mattermost

Mattermost brings team communication together in channels and direct messages. File sharing, search and integrations connect conversations with other workflows.

  • Team Chat

Zulip

Zulip organizes team conversations into channels and topics. Searchable messages and direct messages support both real-time and asynchronous communication.

  • Team Chat