Can I open-source Mattermost Professional?
YES · mature open-source replacementYes. Rocket.Chat Community (46k stars), Discourse (44k stars), Mattermost Team Edition (39k stars) are mature open-source replacements for Mattermost Professional — self-host with real ops work and stop paying $10/mo.
People still pay for Mattermost Professional 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.
xmanaged operations, mobile push, enterprise security, support, and governance
xnetwork effects
xnative mobile apps
xvideo and voice infrastructure
xenterprise moderation and discovery
These projects already replace it, free.
RRocket.Chat CommunityChannels, threads, search and integrations for up to a hundred concurrent users; MongoDB joins the team.open source↗MMattermost Team EditionMattermost without the invoice: full team chat below 250 users, but no SSO and every server problem belongs to you.open source↗ZZulipEmail-shaped topics inside team chat; excellent for async work and merciless about naming conversations.open source↗What each one is, in full: Rocket.Chat Community · Mattermost Team Edition · Zulip
all 5 open-source alternatives to Mattermost Professional →· no votes, no pay-to-list · just what's real
Can I open-source Mattermost Professional?
Yes. Rocket.Chat Community replaces Mattermost Professional 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 Mattermost Professional cost?
Mattermost Professional costs about $10/month (Professional, checked 2026-07-31), which is $120 per year. That's what you save by replacing it with open source.
What do I lose by replacing Mattermost Professional?
Honestly: managed operations, mobile push, enterprise security, support, and governance; 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 Mattermost Professional?
Yes: Rocket.Chat Community (Channels, threads, search and integrations for up to a hundred concurrent users; MongoDB joins the team.) Mattermost Team Edition (Mattermost without the invoice: full team chat below 250 users, but no SSO and every server problem belongs to you.) Zulip (Email-shaped topics inside team chat; excellent for async work and merciless about naming conversations.) All 5 curated open-source alternatives are at caniopensourceit.online/mattermost-professional/alternatives.