Team chat
Self-hosted alternatives to Slack, priced
3 open-source tools that can replace Slack, each shown with what it would actually cost to run for a team of 10 people. Slack on the Pro tier costs $95.63 a month at that size.
| Tool | Server only | With your time | vs Slack | Operational weight | Licence |
|---|---|---|---|---|---|
| Mattermost | $26.40 | $139 | -$2,008 | medium | source-available |
| Rocket.Chat | $46.80 | $159 | -$2,742 | medium | source-available |
| Zulip | $46.80 | $272 | -$7,542 | hard | Apache-2.0 |
The final column is the 36-month difference: positive means self-hosting is cheaper.
Which one to pick
Mattermost 39,042 stars
Go server with PostgreSQL. Unlimited searchable history is the whole point: Slack's free tier hides the archive, and that is what pushes teams onto a paid plan.
At 10 people it needs 2.6 GB of memory and 25 GB of disk, which fits the Starter 4 GB at VPSServer for $22.00 a month. Setting it up is roughly 6 hours of work, then 1.5 hours a month to keep it healthy.
Full Slack versus Mattermost breakdown · Mattermost at every team size
Rocket.Chat 46,107 stars
Node with MongoDB. The MongoDB replica-set requirement is the part that surprises people during the first upgrade.
At 10 people it needs 5.2 GB of memory and 30 GB of disk, which fits the Starter 8 GB at VPSServer for $39.00 a month. Setting it up is roughly 6 hours of work, then 1.5 hours a month to keep it healthy.
Full Slack versus Rocket.Chat breakdown · Rocket.Chat at every team size
Zulip 25,882 stars
Django with PostgreSQL, Redis, RabbitMQ and memcached. The topic-threaded model is genuinely better for asynchronous work than Slack's channels.
At 10 people it needs 5.2 GB of memory and 30 GB of disk, which fits the Starter 8 GB at VPSServer for $39.00 a month. Setting it up is roughly 16 hours of work, then 3 hours a month to keep it healthy.
Full Slack versus Zulip breakdown · Zulip at every team size
How the pricing was established
Slack pricing was read from its own pricing page on 2026-10-09, quoted in euros and converted at 1.1592 dollars to the euro, the Frankfurter, European Central Bank reference rates rate for 2026-09-11. Server prices come from the providers listed on the hosting page. The sizing model and the cost of your time are set out in full on the methodology page.