Open-source alternatives to Slack
10 self-hostable open-source projects that replace Slack, ranked by computed health score with real self-hosting cost. Save up to $34/yr per seat by self-hosting on a $4.13/mo VPS.
Why people leave Slack
- Free tier hides messages older than 90 days
- Per-seat pricing ($7-15/user/mo) gets expensive past 20 people
- No self-hosting option even on Enterprise Grid
- Storage is capped per workspace
Mattermost, Rocket.Chat, and Zulip give the same channels, threads, and integrations on your infra with full message history forever.
The 10 alternatives, ranked by health
Health score is a 6-dimension composite. See methodology for formula and weights.
Zulip server and web application. Open-source team chat that helps teams stay productive and focused.
The Secure CommsOS™ for mission-critical operations
Slack API in Go
Automated developer-oriented status page with alerting and incident support
Lightweight library for web server applications in Swift on macOS and Linux powered by coroutines.
All new design. Inspect your iOS application at runtime.
Open-source and local-first Slack and Notion alternative that puts you in control of your data
Monitor your Website and APIs from your Computer. Get Notified through Slack, E-mail when your server is down or response time is more than expected.
A community discussion platform: Brings together the main features from StackOverflow, Slack, Discourse, Reddit, and Disqus blog comments.
The easy-to-use open source Business Intelligence and Embedded Analytics tool that lets everyone work with data
Cost comparison vs Slack
Self-hosting cost on cheapest plan meeting requirements vs Slack entry tier ($7/mo).
| Project | Self-host /mo | Slack /mo | Save /yr | |
|---|---|---|---|---|
| zulip | $4.13 | $7+ | $34 | Deploy → |
| Rocket.Chat | $4.13 | $7+ | $34 | Deploy → |
| slack | $4.13 | $7+ | $34 | Deploy → |
| gatus | $4.13 | $7+ | $34 | Deploy → |
| Zewo | $4.13 | $7+ | $34 | Deploy → |
| Peek | $4.13 | $7+ | $34 | Deploy → |
| colanode | $4.13 | $7+ | $34 | Deploy → |
| statusok | $4.13 | $7+ | $34 | Deploy → |
Pick your alternative
Most operators land on zulip (top health score in this category; cheapest VPS path is zulip on hetzner for $4.13/mo).
Data refreshed daily. Pricing for Slack sourced from official site.