Slack vs Mattermost

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	Slack Free plan · from $7.25/user/mo Visit Remove	Mattermost Contact sales Visit Remove
What it is	Team messaging built around channels, with huddles, canvases and workflow automation	Self-hosted team messaging and workflow platform for security-sensitive organizations
Free plan	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	No
Cheapest paid plan	$7.25/user/mo billed annually (Pro)Slack pricing	Not publishedMattermost pricing
What it covers	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.	Not stated
Free trial	None stated	A 1-hour trial environment is offered from the Try Mattermost menu; no longer trial terms were stated
Platforms	Web, Windows, Mac, iOS, Android	Web, Windows, Mac, Linux, iOS, Android, Self-hosted
Integrations (vendor's figure)	Over 2,600 apps in the Slack Marketplace	Not stated
Open source	No	Yes, self-hostable
Good for	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	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
Watch out for	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	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
Made by	Slack Technologies (Salesforce)	Mattermost

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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