Can I open-source Slack Pro?
YES · mature open-source replacementYes. Rocket.Chat Community (46k stars), Discourse (44k stars), Mattermost Team Edition (39k stars) are mature open-source replacements for Slack Pro — self-host with real ops work and stop paying $8.75/mo.
People still pay for Slack Pro because community software is valuable when members are already there and the operator does not have to own realtime reliability and abuse response. The recurring cost buys realtime delivery, notifications, abuse handling, search, media, permissions, mobile clients, backups, and community operations, not just the visible interface.
xexisting team network, integrations, push delivery, enterprise controls, and global reliability
xnetwork effects
xnative mobile apps
xvideo and voice infrastructure
xenterprise moderation and discovery
These projects already replace it, free.
RRocket.Chat CommunityChannels, threads, files and integrations for up to a hundred concurrent users; MongoDB is the hidden teammate.open source↗MMattermost Team EditionSlack-shaped chat below 250 users, self-hosted; the subscription disappears and the pager appears.open source↗ZZulipTopic-first team chat with full history and excellent search; fewer drive-by messages survive.open source↗What each one is, in full: Rocket.Chat Community · Mattermost Team Edition · Zulip
all 5 open-source alternatives to Slack Pro →· no votes, no pay-to-list · just what's real
Slack Pro pricing
| plan | monthly | annual (per mo) | what you get |
|---|---|---|---|
| free | $0/workspace | $0/workspace | 90 days of searchable message/file history; up to 10 app integrations; 1:1 huddles; 1:1 Slack Connect |
| pro | $8.75/user | $7.25/user | Unlimited message/file history and integrations; group huddles; Slack Connect with up to 250 organizations |
| business+ | $18/user | $15/user | Unlimited history/integrations; group huddles; up to 250 Slack Connect organizations; SAML SSO and SCIM; 4-hour support response |
| enterprise+ | custom | — | Enterprise organization, security, compliance and administration |
free tier90-day message/file history; 10 app integrations; 1:1 huddles; 1:1 Slack Connect
billingmonthly + annual
hidden costsA paid plan applies to the whole workspace. Active-member/fair-billing adjustments are prorated; multi-channel guests count as paid members while eligible single-channel guests can be free. The advertised 50%-for-3-months offer is temporary and only for eligible new monthly-billed workspaces.
verified 2026-08-12 · source ↗
Can I open-source Slack Pro?
Yes. Rocket.Chat Community replaces Slack Pro today — self-host it on your own server or machine with no subscription. The full list of open-source alternatives is on this page.
How much does Slack Pro cost?
Slack Pro costs about $8.75/month (Pro, checked 2026-07-31), which is $105 per year. That's what you save by replacing it with open source.
What do I lose by replacing Slack Pro?
Honestly: existing team network, integrations, push delivery, enterprise controls, and global reliability; network effects; native mobile apps; video and voice infrastructure; enterprise moderation and discovery. If any of those are load-bearing for you, keep paying.
Is there an open-source alternative to Slack Pro?
Yes: Rocket.Chat Community (Channels, threads, files and integrations for up to a hundred concurrent users; MongoDB is the hidden teammate.) Mattermost Team Edition (Slack-shaped chat below 250 users, self-hosted; the subscription disappears and the pager appears.) Zulip (Topic-first team chat with full history and excellent search; fewer drive-by messages survive.) All 5 curated open-source alternatives are at caniopensourceit.online/slack-pro/alternatives.