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Comparison · Team chat software

Mattermost vs Slack: which is better in 2026?

Mattermost88.5#4 in best team chat softwareSlack93.0#1 in best team chat software

Slack ranks higher in our list of team chat software (#1 against #4, score 93.0 against 88.5).

How we rank Share

  • 88.5
    Editorial score
    93.0
  • 2
    Platforms
    6
  • Yes
    Free to use
    Yes
  • Yes
    Open source
    No

Which should you choose?

Choose Mattermost if you want

Regulated teams that must keep chat on their own servers.

Self-hosted team chat for private cloud and air-gapped networks, with source published under AGPL-3.0. It asks more of an IT team than Slack, and its Enterprise features sit in paid editions.

Choose Slack if you want

Teams that want the largest app ecosystem.

The widest app and integration catalog here, with huddles, Slack Connect and a free plan that never expires. Its code is closed, and cost rises per user as a team grows.

The main differences

  • Only Slack runs on Linux.
  • Only Slack runs on Windows.
  • Only Slack runs on macOS.
  • Only Slack runs on iOS.
  • Only Slack runs on Android.
  • Mattermost is open source; Slack is not.

Side by side

MattermostSlack
Score88.593.0
Rank in list#4 of 10#1 of 10
PriceFree plan, paid upgradesSource is open; paid Enterprise editions for organizationsFree plan, paid upgradesFree plan with 90 days of message history; paid plans per user
Free to useYesYes
Open sourceYesNo
PlatformsWebSelf-hostedWeb, Self-hostedWebWindowsmacOSLinuxiOSAndroidWeb, Windows, macOS, Linux, iOS, Android
Made byMattermost, Inc.Not stated
HostingSelf-hosted or private cloudHosted by Slack
Best forRegulated teams that must keep chat on their own serversTeams that want the largest app ecosystem
Strengths
  • Open source with self-hosting on your own servers
  • Works in private cloud and air-gapped networks
  • Source published under AGPL-3.0
  • Large catalog of apps and integrations
  • Huddles, clips and canvases in one workspace
  • Slack Connect works with outside partners
Limits
  • Running the server needs an IT team
  • Enterprise features are only in paid editions
  • Free plan keeps only 90 days of message history
  • Costs rise per user as a team grows
LinksVisit site Visit site

Questions about Mattermost vs Slack

Is Slack better than Mattermost?
Slack ranks higher in our list of team chat software (#1 against #4, score 93.0 against 88.5). Mattermost is best for: regulated teams that must keep chat on their own servers. Slack is best for: teams that want the largest app ecosystem.
Which is cheaper, Mattermost or Slack?
Mattermost: Source is open; paid Enterprise editions for organizations. Slack: Free plan with 90 days of message history; paid plans per user.
Do Mattermost and Slack run on the same platforms?
Mattermost supports Web, Self-hosted. Slack supports Web, Windows, macOS, Linux, iOS, Android.

Choosing between the two

Learning Center
1:17Beginner · 4 min readHow to decide between two good optionsSettle a close call by sorting it by how hard it is to undo, setting a deadline, scoring the criteria as a tie-breaker and writing down why you chose.1:20Beginner · 6 min readHow to compare products fairly: what to keep in mindDefine the job, cap the must-haves, compare like with like, count total cost over one period and weigh the criteria. Includes a worked example.

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