Comparison

Mattermost vs Slack

On the evidence we track, Slack leads this comparison with a composite score of 79/100. Scores are only directly comparable because these tools share a category; the full breakdown and every source is below.

Mattermost full profile →Slack full profile →

Machine formatsMarkdownJSONGraphQLMarkdown is open. JSON and GraphQL need a free key.

Mattermost67

★Slack79

Attribute comparison across 2 tools
Attribute	Mattermost	SlackLeader
vioscaleAI score	67 / 100medium · 65%	79 / 100medium · 51%
Pricing
Free tierpricing.free_tier	✓	✓
Modelpricing.model	freemium	commercial
Price levelpricing.price_level	low	low
Transparentpricing.transparent	✗	✓
Integrations
Countintegrations.count	700	2,500
Security
Certificationssecurity.certifications	Section 508 Compliance	-
Disclosure policysecurity.disclosure_policy	✓	✓
Gdprsecurity.gdpr	✓	✓
Scorecardsecurity.scorecard	7.3	-
Trust centersecurity.trust_center	https://mattermost.com/blog/trusted-device-authentication-101/	https://slack.com/blog/collaboration/security-at-slack-how-slack-protects-your-data
Vulnerabilitiessecurity.vulnerabilities	Count: 0 · Source: https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=npm&package_name=mattermost-redux&per_page=100 · Last 12m: 0	-
Reliability
Status pagereliability.status_page	✓	✓
Adoption
Dependent reposadoption.dependent_repos	371	-
Github starsadoption.github_stars	39,264	-
Activity
Commits last 30dactivity.commits_last_30d	100	-
Release
Cadence daysrelease.cadence_days	1	-
Historyrelease.history	20 items	-
Language
Primarylanguage.primary	TypeScript	-
Market
Availabilitymarket.availability	Available worldwide	Available worldwide
Content
Faqcontent.faq	7 items	6 items

Score

vioscaleAI score

Mattermost67 / 100medium · 65%

Slack79 / 100medium · 51%

Pricing

Free tier

Mattermost✓

Slack✓

Model

Mattermostfreemium

Slackcommercial

Price level

Mattermostlow

Slacklow

Transparent

Mattermost✗

Slack✓

Integrations

Count

Mattermost700

Slack2,500

Security

Certifications

MattermostSection 508 Compliance

Slack–

Disclosure policy

Mattermost✓

Slack✓

Gdpr

Mattermost✓

Slack✓

Scorecard

Mattermost7.3

Slack–

Trust center

Mattermosthttps://mattermost.com/blog/trusted-device-authentication-101/

Slackhttps://slack.com/blog/collaboration/security-at-slack-how-slack-protects-your-data

Vulnerabilities

MattermostCount: 0 · Source: https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=npm&package_name=mattermost-redux&per_page=100 · Last 12m: 0

Slack–

Reliability

Status page

Mattermost✓

Slack✓

Adoption

Dependent repos

Mattermost371

Slack–

Github stars

Mattermost39,264

Slack–

Activity

Commits last 30d

Mattermost100

Slack–

Release

Cadence days

Mattermost1

Slack–

History

Mattermost20 items

Slack–

Language

Primary

MattermostTypeScript

Slack–

Market

Availability

MattermostAvailable worldwide

SlackAvailable worldwide

Content

Faq

Mattermost7 items

Slack6 items

Capabilities

Feature-by-feature on the axes that matter for collaboration software. “-” means undocumented, not absent.

Capability comparison for Collaboration Software
Capability	Mattermost	Slack
Modality
Messaging	✓	✓
Video meetings	✗	✓
Whiteboard	✗	-
Meetings
Screen sharing	✓	-
Recording / transcription	Recording + AI notes	Recording + AI notes
Security
End-to-end encryption	-	-
SSO / SCIM	✓	✓
Access
Guest / external access	✓	✓
Compliance
Compliance controls	✓	✓
Deployment
Hosting	Cloud + self-hosted	Cloud only
Scale
Max participants	-	-
Ecosystem
App marketplace	✓	✓
Public API / bot framework	✓	✓
Commercial
Free tier	✓	-

Modality

Messaging

Mattermost✓

Slack✓

Video meetings

Mattermost✗

Slack✓

Whiteboard

Mattermost✗

Slack-

Meetings

Screen sharing

Mattermost✓

Slack-

Recording / transcription

MattermostRecording + AI notes

SlackRecording + AI notes

Security

End-to-end encryption

Mattermost-

Slack-

SSO / SCIM

Mattermost✓

Slack✓

Access

Guest / external access

Mattermost✓

Slack✓

Compliance

Compliance controls

Mattermost✓

Slack✓

Deployment

Hosting

MattermostCloud + self-hosted

SlackCloud only

Scale

Max participants

Mattermost-

Slack-

Ecosystem

App marketplace

Mattermost✓

Slack✓

Public API / bot framework

Mattermost✓

Slack✓

Commercial

Free tier

Mattermost✓

Slack-

What each one is

The product in its own terms, so the numbers below have context.

Mattermost

Mattermost is a self-hosted or cloud-based collaboration platform offering secure messaging, voice calling, screen sharing, workflow automation, and AI-assisted tools for teams and enterprises.

Independently observed

Slack

Leader

Slack is a cloud-based system that enables teams to communicate through channels, integrate with external tools, and automate workflows while maintaining enterprise-grade security and compliance controls.

Independently observed

Pricing

List pricing as published by each vendor, with the date we read it. Always verify at the source before you buy.

Mattermost

HybridFree tier

Enterprise Edition E10-
Enterprise Edition E20-

as of 2026-10-05verify ↗

Slack

Leader

from £5.75/moSubscriptionFree tier

From £0 (free tier) to £7/user/month (Pro). Free tier available.

FreeFree
- 90 days of message history
- Up to 10 apps from Slack App Directory
- 1:1 audio and video meetings with screen sharing
- 1:1 external messages via Slack Connect
- SAML-based single sign-on
- +9 more
Pro£7/user/month (£5.75/user/month billed annually)
- Unlimited message history
- Unlimited app integrations
- 2,600+ apps in Slack App Directory

as of 2026-08-05verify ↗

Platform & deployment

Where each product runs and how it can be hosted. A dash means undocumented, not unsupported.

Platform and deployment support comparison
Supports	Mattermost	Slack
WebPlatforms	✓	✓
iOSPlatforms	✓	✓
AndroidPlatforms	✓	✗
macOSPlatforms	✓	✗
WindowsPlatforms	✓	✗
LinuxPlatforms	✓	✗
Cloud / SaaSDeployment	✓	✓
Self-hostedDeployment	✓	✗
On-premiseDeployment	✓	✗
Air-gappedDeployment	✓	✗

Platforms

Web

Mattermost✓

Slack✓

iOS

Mattermost✓

Slack✓

Android

Mattermost✓

Slack✗

macOS

Mattermost✓

Slack✗

Windows

Mattermost✓

Slack✗

Linux

Mattermost✓

Slack✗

Deployment

Cloud / SaaS

Mattermost✓

Slack✓

Self-hosted

Mattermost✓

Slack✗

On-premise

Mattermost✓

Slack✗

Air-gapped

Mattermost✓

Slack✗

Integrations

What each product connects to. Counts come from the vendor's own integration directory where one exists.

In common (1)

GitHub

Mattermost

26 total - 25 not shared

Slack
Git
Jenkins
GitLab
Twitter
Bugzilla
RSS
Gerrit
Redmine
Mercurial
SVN
Threema
Pexip
Prometheus
Grafana
Microsoft Teams
Matrix
XMPP
Trello
ServiceNow
PagerDuty
Splunk
Nagios
Ansible
+1 more

Independently observed

Slack

Leader

15 total - 14 not shared

Salesforce
Atlassian
Lucid
Loom
Miro
Smartsheet
Mural
Zapier
Microsoft 365
Jira
Google Workspace
Okta
ADFS
Zendesk

Independently observed

Still deciding?

Mattermost or Slack: which one depends on you

A composite score cannot know your constraints. Describe them and both get re-weighted against what you actually need, with the evidence behind every position.

Free to run, no account needed to start. How the evaluation works

Comparison generated from independently-sourced facts. Every value links to its source and retrieval date. See the method.