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Should I Use Mattermost.com?

mattermost.com·Analyzed 1 hour ago··Based on 10 sources

Accelerate your mission critical workflow by integrating people, processes, tools and AI infrastructure on a resilient and adaptable platform.

Depends

Depends

Buy if you're a regulated, defense, or government team that must self-host chat and has ops staff to run it.

Enterprise self-hosted Slack alternative for regulated teams — heavy ops burden, shrinking free tier, mixed reviews.

Confidence: Medium

4.3/5

G2 rating

369 reviews

2.9/5

Trustpilot

Average TrustScore

$70M

Total funding

incl. $50M Series B, 2019

$33.1M

Est. ARR

2024 estimate

Value for money2

10k-message caps, hidden costs, shrinking free tier

Ease of use2

Self-hosting burden; mobile app called extremely slow

Feature depth4

Integrates Jira, GitLab, ServiceNow, PagerDuty; plugin platform

Security posture3

Public bug bounty, but recent critical CVEs

Pros

  • Open-source and self-hosted; data stays on your infrastructure²
  • Rated 4.3/5 on G2 across 369 reviews
  • Integrates Jira, ServiceNow, GitLab, PagerDuty out of the box
  • Public bug bounty and regular dependency vulnerability scans
  • Purpose-built for sovereign and air-gapped environments¹

Cons

  • Trustpilot score sits at just 2.9⁵
  • Mobile app users report it is 'extremely slow'⁶
  • Free option removed from the public pricing page
  • Recent CVEs include a server auth bypass⁸
  • Community sees v10 as the end of free open-source Mattermost⁷

Gotchas

  • highEntry edition locks message history after 10,000 messages — older messages sit behind paid plans.
  • mediumFree option was pulled from the pricing page; downgrade paths from paid editions are murky.
  • mediumThird-party breakdowns flag hidden costs behind the headline pricing.
  • mediumSelf-hosting means you own upgrades, backups, and patching every new CVE.

Best for

  • Defense and government contractors
  • Regulated industries needing self-hosting
  • DevOps and engineering teams
  • Air-gapped or sovereign deployments

Not for

  • Small teams that just want a group chat
  • Companies with no sysadmin or DevOps staff
  • Anyone expecting a durable free tier
  • Mobile-first teams

Companies that use it

  • Fairphone
  • Schäferbarthold
  • Data For Good

Pricing

Entry

Free (self-hosted)

  • Channel-based messaging
  • 10,000-message history cap

Professional

See mattermost.com/pricing

  • Advanced messaging features
  • Per-seat licensing

Enterprise

Not disclosed

  • Compliance and government options
  • Custom contracts

Security

Active security program with bug bounty and routine scans, but several recent CVEs are disclosed, including an auth bypass.

  • CVE-2026-6339 — Mattermost Server auth bypassAuthentication bypass vulnerability disclosed May 2026.⁸
  • CVE-2025-24490 — SQL injectionPart of multiple critical vulnerabilities flagged in Mattermost Collaboration, February 2025.⁹
  • CVE-2025-58075NVD assessment not yet published as of October 2025.
  • CERT-FR advisory on Mattermost ServerFrench national CERT (ANSSI) published a vulnerability notice citing data integrity risk.

What users say

Engineers praise the self-hosted threading model while users report slow mobile apps, message-history paywalls, and shrinking free features.

“Extremely slow.”
— Google Play review
“Is v10 the practical end of "Free and Open Source Mattermost"”
— Reddit, r/Mattermost
“Mattermost disqualifying itself from further self hosted usage”
— Reddit, r/Mattermost

Alternatives

Compare Mattermost.com with each alternative.

Discord

Free, easy group chat for small non-regulated teams.

Full analysis

Based on ~50 public sources including G2, Trustpilot, Reddit, Google Play, CVE databases, and vendor pages.

Sources

  1. Mattermost Pricingmattermost.com
    official
  2. Mattermost on GitHub (open source)github.com
    official
  3. Mattermost Security Updatesmattermost.com
    official
  4. Mattermost reviews on G2g2.com
    review
  5. Mattermost on Trustpilottrustpilot.com
    review
  6. Mattermost on Google Playplay.google.com
    review
  7. Reddit, r/Mattermost on v10 open-source changesreddit.com
    review
  8. CVE-2026-6339 auth bypass (SentinelOne)sentinelone.com
    security
  9. Multiple Critical Vulnerabilities in Mattermost (Censys)censys.com
    security
  10. Mattermost funding and ARR (GetLatka)getlatka.com
    news

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