Mattermost vs Rocket.Chat vs Slack

Pick up to 4 tools and see their free plans, entry prices, platforms and limits in one table. Every fact comes from each vendor's own pages, checked 7 November 2026.

Compared on	Mattermost Contact sales Visit Remove	Rocket.Chat Free plan Visit Remove	Slack Free plan · from $7.25/user/mo Visit Remove
What it is	Self-hosted team messaging and workflow platform for security-sensitive organizations	Self-hostable secure messaging platform with Matrix and XMPP federation	Team messaging built around channels, with huddles, canvases and workflow automation
Free plan	No	Starter is described as a free self-managed workspace for technical evaluation, small businesses and non-profits; its user and feature limits were not shown on the pages read	Free plan keeps 90 days of message history, allows up to 10 app integrations, and limits huddles and Slack Connect external messages to 1:1
Cheapest paid plan	Not publishedMattermost pricing	Not publishedRocket.Chat pricing	$7.25/user/mo billed annually (Pro)Slack pricing
What it covers	Not stated	Not stated	List prices. Slack also lists a 50% promotional price for the first 3 months on monthly Pro billing for teams that buy online within 7 days of creating the workspace. Members active in a 28-day period are billed.
Free trial	A 1-hour trial environment is offered from the Try Mattermost menu; no longer trial terms were stated	None stated	None stated
Platforms	Web, Windows, Mac, Linux, iOS, Android, Self-hosted	Web, Windows, Mac, Linux, iOS, Android, Self-hosted	Web, Windows, Mac, iOS, Android
Integrations (vendor's figure)	Not stated	Not stated	Over 2,600 apps in the Slack Marketplace
Open source	Yes, self-hostable	Yes, self-hostable	No
Good for	Government and defense teams that must keep chat on their own infrastructure Engineering and security operations teams running incident response in chat Regulated companies that need retention and audit controls	Public sector and defense teams that need to host chat themselves Organizations that want to federate with Matrix or XMPP users Teams replacing an older on-premises chat system	Teams that want channel-based conversation with a large set of connected apps Companies that need to message people at other organizations through Slack Connect Workspaces that want to automate approvals and routine requests without code
Watch out for	Prices are not published; the pricing page directs buyers to sales Licenses are sold as prepaid annual per-seat subscriptions, with each server needing its own license Marketing focuses on high-security sectors, so it may be more than a small team needs	Commercial pricing is not published The home page markets mainly to defense, government and critical infrastructure Licence terms were not stated on the pages read	The Free plan keeps only 90 days of message history and 10 apps Group huddles and group external messages need a paid plan Single sign-on needs Business+ and above
Made by	Mattermost	Rocket.Chat	Slack Technologies (Salesforce)

Entry prices are the cheapest paid plan, as each vendor publishes it; “What it covers” says what that price is per (a user, a channel, a brand, a number of contacts). The sources are listed on each tool's page.

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