Softwr

Communication · head to head

Mattermost vs Slack

Mattermost logo

Mattermost

Communication

Channel-centric collaboration for secure workflows

From
On request
Rated
-
Full reviewWebsite
Slack logo

Slack

Communication

Where work happens

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Slack has a free tier, so it costs nothing to try first.
  • Each has a real cost: Mattermost no published pricing on public website; requires sales contact for all tiers; Slack 90-day message history limit on free plan results in important conversations disappearing
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Mattermost and Slack actually diverge.

Attributes where Mattermost and Slack differ
AttributeMattermostSlack
Starting priceOn requestFree
Pricing modelquoteUnknown
Free tierNoYes
PlatformsWebWeb, iOS, Android, macOS, Windows, Linux
FoundedUnknown2009

Identical on both: user rating (Not yet rated), category (Communication).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Mattermost

Nothing recorded that Slack does not also cover.

Only in Slack

  • Channels
  • Direct messaging
  • Voice & video calls
  • Screen sharing
  • File sharing
  • Search
  • Workflow builder
  • Slack Connect

What people use each for

The jobs each tool is most often brought in to do.

Mattermost

  • Team messaging and collaborationnot Slack
  • Secure enterprise communicationnot Slack
  • On-premise or self-hosted deploymentnot Slack

Slack

  • Team communicationnot Mattermost
  • Project coordinationnot Mattermost
  • Customer supportnot Mattermost
  • Remote worknot Mattermost
  • Cross-functional collaborationnot Mattermost

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Mattermost

  • No published pricing on public website; requires sales contact for all tiers
  • Three tiers (Professional, Enterprise, Enterprise Advanced) have feature differences but no cost transparency
  • User scaling caps differ between tiers without public price justification

Slack

  • 90-day message history limit on free plan results in important conversations disappearing
  • Per-user pricing becomes expensive quickly for larger teams
  • Notification overload with 78% of employees feeling overwhelmed by notifications
  • Mobile app performance issues including lag and slow syncing
  • Huddles limited to 50 people and cannot be recorded
  • Requires dedicated video conferencing service for formal meetings and webinars

Pricing, plan by plan

Mattermost

On request

No published plan breakdown. See the Mattermost review.

Slack

Free

No published plan breakdown. See the Slack review.

Which should you pick?

Choose Mattermost if

Nothing in the data separates Mattermost from Slack on the points above - pick on price and on how each one feels to use.

Mattermost review

Choose Slack if

  • You need channels.
  • You want to start without paying.
  • You work on Web, iOS, Android, macOS, Windows, Linux.
  • You also want direct messaging.
Slack review

Questions people ask

Is Mattermost or Slack better?
Neither clearly leads. Mattermost starts at On request and Slack at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Mattermost or Slack?
Slack has a free tier; the other does not. Paid plans start at On request for Mattermost and Free for Slack.
Does Mattermost or Slack run on more platforms?
Mattermost runs on Web. Slack runs on Web, iOS, Android, macOS, Windows, Linux.
Can I use Slack for free?
Yes. Slack has a free tier, so you can try it without paying. Mattermost starts at On request.
What is Mattermost best used for?
Mattermost is most often used for team messaging and collaboration, secure enterprise communication, on-premise or self-hosted deployment. Of those, team messaging and collaboration and secure enterprise communication are not what Slack is typically brought in for.
What can Mattermost do that Slack cannot?
Slack covers Channels, Direct messaging, Voice & video calls, Screen sharing.

Answered from the vendors’ own pages

Mattermost: What user limits apply to each Mattermost pricing tier?

Professional tier supports maximum 250 users. Enterprise scales to 50,000 concurrent users. Enterprise Advanced scales to 200,000 concurrent users. Exact per-user costs not stated.

Source
Slack: Does Slack have a free plan?

Yes, Slack offers a free plan indefinitely with no credit card required. Free users get 90-day message history, up to 10 app integrations, and 1:1 huddles.

Source
Mattermost: What support response times are included with each plan?

Professional includes community support plus business hours professional support with next business day response. Enterprise includes 24x7 support with 4-hour response time. Enterprise Advanced includes 24x7 with Premier Support option.

Source
Slack: What are Slack's pricing plans?

Slack offers Free, Pro ($7.25/user/month with annual billing), Business+ ($12.50/user/month), and Enterprise Grid (custom pricing). Monthly billing costs approximately 20% more than annual.

Source
Mattermost: How much does Mattermost cost for teams under 250 users?

Pricing for Professional tier with user counts under 250 is not disclosed publicly. Contact Mattermost sales for specific quotes.

Source
Slack: Does Slack support offline use?

Slack is a cloud-based platform and does not support robust offline work. Internet connectivity is required to access messages and collaborate.

Source
Slack: What integrations does Slack support?

Slack integrates with 43+ apps on average per team, including Google Drive, ChatGPT, Vercel, Asana, GitHub, and many others through their app marketplace.

Source
Share

Related pages

More on Mattermost

More on Slack

Keep looking

Other head to heads