Comparison

Mattermost vs Slack

On the evidence we track, Slack leads this comparison with a composite score of 82/100. 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 →

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Mattermost59

★Slack82

Attribute comparison across 2 tools
Attribute	Mattermost	SlackLeader
Vioscale score	59 / 100medium · 66%	82 / 100medium · 54%
Pricing
Free tierpricing.free_tier	✓	✓
Modelpricing.model	commercial	commercial
Price levelpricing.price_level	low	low
Transparentpricing.transparent	✗	✓
Integrations
Countintegrations.count	14	2,500
Security
Disclosure policysecurity.disclosure_policy	✓	✓
Gdprsecurity.gdpr	✓	✓
Scorecardsecurity.scorecard	7.3	-
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	38,909	-
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 · Popular in US, CA, GB, EU, JP · HQ US	Available worldwide

Score

Vioscale score

Mattermost59 / 100medium · 66%

Slack82 / 100medium · 54%

Pricing

Free tier

Mattermost✓

Slack✓

Model

Mattermostcommercial

Slackcommercial

Price level

Mattermostlow

Slacklow

Transparent

Mattermost✗

Slack✓

Integrations

Count

Mattermost14

Slack2,500

Security

Disclosure policy

Mattermost✓

Slack✓

Gdpr

Mattermost✓

Slack✓

Scorecard

Mattermost7.3

Slack–

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

Mattermost38,909

Slack–

Activity

Commits last 30d

Mattermost100

Slack–

Release

Cadence days

Mattermost1

Slack–

History

Mattermost20 items

Slack–

Language

Primary

MattermostTypeScript

Slack–

Market

Availability

MattermostAvailable worldwide · Popular in US, CA, GB, EU, JP · HQ US

SlackAvailable worldwide

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	-	-
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

Mattermost-

Slack-

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 an open-source messaging and collaboration platform designed for organizations requiring data sovereignty, self-hosting control, and mission-critical availability. It integrates with external tools and workflows, supports high-availability deployments, and serves government, defense, and enterprise customers needing secure, compliant operations.

Independently observed

Slack

Leader

A workspace tool that consolidates team messaging, third-party software integrations, and automated workflows to help distributed teams coordinate work and manage customer interactions more effectively.

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

Free open-source tier available; commercial E10 and E20 enterprise editions

Open SourceFree
Enterprise E10-
Enterprise E20-

as of 2026-08-14verify ↗

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	✓	✓
Cloud / SaaSDeployment	✓	✓
Self-hostedDeployment	✓	✗
On-premiseDeployment	✓	✗
HybridDeployment	✓	✗

Platforms

Web

Mattermost✓

Slack✓

iOS

Mattermost✓

Slack✓

Deployment

Cloud / SaaS

Mattermost✓

Slack✓

Self-hosted

Mattermost✓

Slack✗

On-premise

Mattermost✓

Slack✗

Hybrid

Mattermost✓

Slack✗

Integrations

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

Mattermost

14 total

Slack
Git
Jenkins
GitLab
GitHub
Twitter
Bugzilla
RSS
Gerrit
Redmine
Mercurial
SVN
Threema
Pexip

Independently observed

Slack

Leader

8 total

Salesforce
Atlassian
Lucid
Loom
Miro
Smartsheet
Mural
Zapier

Independently observed

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