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Team Chat Software · Rank #3 of 10

Mattermost review and pricing

Self-hosted open-source team chat for defense, intelligence, and regulated buyers.

By Mattermost · Founded 2016 · Palo Alto, CA · private

Mattermost is the leading open-source self-hosted team chat platform, founded 2016 by Ian Tien out of an internal SpinPunch game-studio chat tool and built deliberately as a Slack alternative for buyers who cannot or will not run Slack Cloud. The company has positioned consistently at defense, intelligence, and heavily regulated buyers; US Department of Defense and allied military customers are publicly disclosed including the US Air Force and the US Navy. Strengths: fully self-hosted on-prem option that meets defense, intelligence, and sovereignty-grade data residency requirements, genuinely open-source core (MIT-licensed Team Edition), strong enterprise admin surface with SAML SSO, audit log, eDiscovery and compliance exports at Enterprise tier, Playbooks for runbook automation that competes with PagerDuty-adjacent workflows, and a defensible procurement story for buyers needing OSS-first software. Trade-offs: self-hosting requires real ops investment with infrastructure, upgrades, and high-availability operations on the buyer, the SaaS Cloud offering is comparatively thin and used mostly as a trial path, the app integration directory is narrower than Slack and Teams, day-to-day UX feels less polished than Slack, and post-2022 product velocity has been steady rather than fast.

Best for

Defense, intelligence, and heavily regulated buyers requiring fully self-hosted team chat on internal infrastructure or air-gapped environments. Particularly strong for US federal and allied military customers, government contractors, banks with strict on-prem requirements, and any organization where Slack Cloud or Teams Cloud is non-starter.

Worst for

SaaS-friendly startups (Slack is easier), Microsoft 365 buyers (Teams is bundled), organizations without ops investment for self-hosting, buyers prioritizing the deepest third-party app surface (Slack still leads), or anyone wanting fast vendor product velocity.

Vendor Trust Score

Is Mattermost a trustworthy vendor?

8.4/10
High trust
Pricing transparency
Published rates; no hidden fees
8.5
Contract fairness
Reasonable terms; no auto-renew traps
8.5
Incident response
How they handle outages and breaches
8.0
Post-acquisition behavior
Customer treatment after M&A or PE
8.5
Executive stability
Leadership churn over 24 months
8.5
Roadmap honesty
Public commitments held
8.5
Trust signal log
  • 2016-05-04
    Mattermost open-sourced as Slack alternative for self-hosted buyers
    Team Edition released under MIT license; positioned consistently at defense, intelligence, and regulated buyers needing on-prem chat.
  • 2021-06-22
    Mattermost raised $50M Series C led by ICONIQ Capital
    Reported total funding around $100M+ across rounds; confirms multi-year product runway for the OSS-first self-hosted positioning.
  • 2023-05-15
    US Department of Defense and allied military customers publicly disclosed
    US Air Force and US Navy among publicly disclosed customers; defensible reference for defense and intelligence procurement.
Vendor Trust is scored independently of product quality. A great product from an unfair vendor still earns a low trust score.
Review Intelligence

What 450 reviews actually say

Synthesized from G2, Capterra, Reddit, Trustpilot. Patterns >15% prevalence shown.

Last synthesized
2026-04-29

Praise patterns

  • Fully self-hosted for sovereignty and defense buyers
    87%
  • Genuinely open-source Team Edition (MIT)
    78%
  • Playbooks useful for runbook and incident response
    71%
  • Defensible OSS-first procurement story
    64%

Complaint patterns

  • Self-hosting requires real ops investment
    51%
  • App integration directory narrower than Slack
    47%
  • Day-to-day UX less polished than Slack
    41%
  • Post-2022 product velocity steady rather than fast
    38%
Sentiment trend (6 months)
78/100 0 pts
12
01
02
03
04
05
Patterns are extracted from review corpus and human-verified. We surface trends, not anecdotes.
Verified Pricing

What buyers actually pay

320 anonymized deal disclosures · last updated 2026-05-01

Contribute your deal price
Company size Median annual
50 to 250 users (Professional) $18,000
250 to 2,500 users (Enterprise) $180,000
2,500+ users (Enterprise) $900,000
Verified pricing is crowdsourced from buyers under anonymity guarantees. Vendor-listed prices are validated against actual deals quarterly.
Compliance & Security

Auto-verified certifications

Verified 2026-05-01
SOC 2 Type II
ISO 27001
HIPAA
GDPR
CCPA
PCI DSS
FedRAMP In-Process

Editorial: Strengths

  • Fully self-hosted on-prem for defense, intelligence, and sovereignty buyers
  • Genuinely open-source Team Edition (MIT license)
  • SAML SSO, audit log, eDiscovery, compliance exports at Enterprise
  • Playbooks for runbook automation (PagerDuty-adjacent workflows)
  • US Department of Defense, US Air Force, US Navy publicly disclosed customers
  • Defensible OSS-first procurement story
  • On-prem deployment on internal infrastructure or air-gapped environments

Editorial: Weaknesses

  • Self-hosting requires real ops investment for upgrades and HA
  • SaaS Cloud offering thin; used mostly as trial path
  • App integration directory narrower than Slack and Teams
  • Day-to-day UX less polished than Slack
  • Post-2022 product velocity has been steady rather than fast
  • Migration off Mattermost (or to it) is non-trivial at scale
  • Smaller vendor footprint; procurement pushback at largest enterprises

Key features & integrations

  • +Channels, threads, direct messages, group chat
  • +Self-hosted on-prem deployment (internal or air-gapped)
  • +Playbooks for runbook and incident-response automation
  • +Boards for in-channel project tracking (Kanban)
  • +SAML SSO, AD LDAP, audit log at Professional and Enterprise
  • +eDiscovery, compliance exports, retention policies at Enterprise
  • +REST API, webhooks, and incoming/outgoing integrations
  • +Mattermost Marketplace for community-built apps
  • +Voice and video calling (native plus Jitsi integration)
  • +End-to-end encryption for direct messages at Enterprise
700+ integrations
GitHubGitLabJenkinsPagerDutyJiraConfluenceMicrosoft 365Google WorkspaceOktaActive Directory
Geography supported
Global; strongest in US, EU, UK, defense allied countries
Best fit
50 to 100,000+ employees · Defense, intelligence, regulated buyers needing self-hosted team chat
Editorial deep-dive

Read our full ranking of Team Chat Software

Mattermost ranks #3 in our editorial review of 10 team chat software platforms. The deep-dive covers methodology, comparison tables, decision matrix, migration scoring, and FAQs.

Read the full ranking

Closest alternatives in Team Chat Software

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