Slack is a cloud-hosted SaaS platform with 750,000+ active workspaces and superior integrations, while Mattermost is a self-hosted open-source alternative costing 60-70% less with full data control. Slack dominates enterprise adoption; Mattermost suits organizations prioritizing privacy and cost savings.
Mattermost vs Slack — Side-by-side comparison on A Versus B
Open-source, self-hosted team collaboration platform designed for organizations requiring data control and customization.
Cloud-based SaaS team communication platform with 750,000+ active workspaces and 2,000+ native integrations.
Deployment Model. Monthly Cost Per User. Third-Party Integrations. Data Ownership. Enterprise Adoption. Open Source Code. Message Search Limit
Choose Mattermost if your organization prioritizes data sovereignty, cost efficiency, and regulatory compliance—it's ideal for government, healthcare, and enterprises with strict security requirements. Choose Slack if you need best-in-class integrations, enterprise support, and seamless team collaboration at scale without infrastructure management overhead.
Mattermost: Self-hosted, on-premise, cloud | Slack: Cloud-based SaaS only
Mattermost: Full control with self-hosting option | Slack: Compliant but data on Salesforce servers
Mattermost: Stable | Slack: No increases for 33 months
Mattermost: Yes, fully open-source | Slack: No, proprietary
Mattermost: Basic automation and workflows | Slack: Advanced AI assistant, smart summaries, automation
Mattermost: $0 (self-hosted) or $10 (cloud) | Slack: N/A
Mattermost: Up to 1,000 (with Jitsi) | Slack: N/A
Mattermost: Open-source (AGPL v3) | Slack: Proprietary/closed
Mattermost: Limited AI features, plugin-based integration possible | Slack: N/A
Mattermost: Full control with self-hosted deployment | Slack: N/A
Mattermost: 500,000+ deployments | Slack: N/A
Mattermost: $0 (open-source) - $39/month (Mattermost Cloud) | Slack: N/A
Mattermost: 100+ GB (configurable) | Slack: N/A
Mattermost: 120+ integrations (community-contributed) | Slack: 2,400+
Mattermost: AGPL v3 open-source | Slack: N/A
Mattermost: Full self-hosted + cloud managed options | Slack: N/A
Mattermost: 0.5-1 second average | Slack: Excellent - optimized search indexing
Annual TCO (1,000 users, 3-year average)
Mattermost: $0 (self-hosted) or $39,000 (managed cloud) | Slack: N/A
Mattermost: 50,000+ | Slack: 750,000+ workspaces
Mattermost: Unlimited | Slack: 10,000 (free), unlimited (paid)
Mattermost: Self-hosted, Cloud, Docker, Kubernetes | Slack: Cloud-only SaaS
Mattermost: Yes (AGPL license) | Slack: No (proprietary)
Mattermost: Varies by provider (24-48h) | Slack: 1-4 hours (Enterprise Grid)
Mattermost: 10GB (self-hosted unlimited) | Slack: 5GB
Mattermost: 500,000+ deployments | Slack: 0.75 million
Mattermost: $0-20 (self-hosted option free) | Slack: $8.25 (Pro plan, min 3 users)
Mattermost: Depends on third-party (Jitsi default 100) | Slack: N/A
Mattermost: No SLA (self-managed) | Slack: 99.99%
Mattermost: Fully supported | Slack: N/A
Mattermost: 200+ community plugins | Slack: N/A
Mattermost: Unlimited (open-source community) | Slack: N/A
Mattermost: N/A | Slack: $87 (billed yearly)
Mattermost: N/A | Slack: Up to 2,000 (with paid plan)
Mattermost: N/A | Slack: Limited (third-party connectors)
Mattermost: N/A | Slack: Slack AI (summarization, search, assisted writing)
Mattermost: N/A | Slack: $3,600 (Pro plan at $15/user)
Mattermost: N/A | Slack: 10,000 most recent
Mattermost: N/A | Slack: Unlimited (Slack Huddles for video limited to 50 participants)
Mattermost: N/A | Slack: Huddles for brief video, limited to 50 participants; requires external tool for full conferencing
Mattermost: N/A | Slack: Not native; requires integration with Otter.ai or similar third-party services
Mattermost: N/A | Slack: 5 out of 5 (core feature with channels, threads, and history)
Mattermost: N/A | Slack: 2 out of 5 (available via integration, not native)
Mattermost: N/A | Slack: 30+ (CRM tools, meeting summaries, automation, SlackBot enhancements)
Mattermost: N/A | Slack: Unlimited group chats
Mattermost: N/A | Slack: Workflow automation, search enhancement
Mattermost: N/A | Slack: Optimized with threads and archives
Mattermost: N/A | Slack: Slack AI (optional on paid plans)
Mattermost: N/A | Slack: Limited (requires custom setup)
Mattermost: N/A | Slack: Advanced with conditional logic
Mattermost: N/A | Slack: Variable by plan
Mattermost: N/A | Slack: Requires 3rd party
Mattermost: N/A | Slack: $150 (billed monthly)
Mattermost: N/A | Slack: 0 (not native feature)
Mattermost: N/A | Slack: Unlimited (slide deck view only)
Mattermost: N/A | Slack: DMs only, Enterprise+ plan
Mattermost: N/A | Slack: Slack AI (search, summarization, drafting)
Mattermost: N/A | Slack: $12.50 per user/month
Mattermost: N/A | Slack: 90 days maximum
Mattermost: N/A | Slack: 15 participants
Mattermost: N/A | Slack: Advanced (Workflow Builder, automations)
Mattermost: N/A | Slack: 2,300+ integrations
Mattermost: N/A | Slack: Unlimited external guests via workspace invite
Mattermost: N/A | Slack: $8-12.50 (Pro/Business+)
Mattermost: N/A | Slack: 10 years standard
Mattermost: N/A | Slack: Channel-based threads (contextual loss in active channels)
Mattermost: N/A | Slack: Native iOS/Android with feature-parity
Mattermost: N/A | Slack: Yes (Slack Huddles)
Paid Workspaces/Users (Enterprise Adoption)
Mattermost: N/A | Slack: 750,000+ paid workspaces
Mattermost: N/A | Slack: $150/month ($1,800/year)
Mattermost: N/A | Slack: 2,400+ integrations
Mattermost: N/A | Slack: 90-day limited access
Mattermost: N/A | Slack: 750,000+ active workspaces
Mattermost: N/A | Slack: No (cloud-only)
Mattermost: N/A | Slack: Yes (Business+ plan required)
Mattermost: N/A | Slack: $12.50/user (Pro plan)
Mattermost: N/A | Slack: 10,000 messages (free); unlimited (paid)
Mattermost: N/A | Slack: No (requires integrations)
Mattermost: N/A | Slack: 50-100ms (instant)
Mattermost: N/A | Slack: 5GB (Free), varies by plan
Mattermost: N/A | Slack: SOC 2 Type II, ISO 27001, FedRAMP
Mattermost: N/A | Slack: 1 GB shared workspace
Annual Subscription Cost (Pro, 100 users)
Maximum video call participants (free tier)
Mattermost: N/A | Slack: 100 participants
Mattermost: N/A | Slack: 90 days searchable
Mattermost: N/A | Slack: 2,000+ apps (Slack App Directory)
Mattermost: N/A | Slack: Cost-effective until ~12 users
Mattermost: N/A | Slack: No: messaging-only, requires integrations
Mattermost: N/A | Slack: 90 days (Free/Pro), unlimited with Enterprise
Mattermost: N/A | Slack: 750+ million messages daily across 750k+ organizations
Monthly Subscription Cost (Pro/Standard)
Mattermost: N/A | Slack: All messages indexed instantly
Mattermost: N/A | Slack: API-based (basic)
Mattermost: N/A | Slack: 100 (workspace)
Maximum Video Conference Participants (Free)
Mattermost: N/A | Slack: Limited (typically 3-4)
Mattermost: N/A | Slack: 4.6/5 (12,400 reviews)
Mattermost: N/A | Slack: Full-text indexed across all messages
Mattermost: N/A | Slack: Partial (DMs only, beta feature)
Cost Per User (Annual, Lowest Paid Tier)
Mattermost: N/A | Slack: Certified (SOC 2 Type II, GDPR)
Monthly Cost Per User (Standard Tier, Annual Billing)
Mattermost: N/A | Slack: 0 GB (integrations only)
Maximum Video Conference Participants (Standard Plan)
Mattermost: N/A | Slack: 10,000 (free tier); unlimited (paid)
Mattermost: N/A | Slack: N/A (proprietary)
How to choose between Mattermost and Slack
Mattermost vs Slack — Structured Comparison Data
Machine-readable comparison dataset for Mattermost vs Slack. Contains 185 attribute comparisons, 5 FAQ pairs.
Mattermost vs Slack — Attribute Category Vocabulary
Taxonomy of attribute categories used to classify comparison data for Mattermost vs Slack.
Is Mattermost truly cheaper than Slack long-term?
Yes, significantly. Mattermost self-hosted costs $4-8 per user monthly, while Slack's Professional plan starts at $8.75/user and Pro at $12.50/user. For a 100-person team over 3 years, Mattermost saves $14,400-$25,200. However, factor in IT infrastructure costs (server, maintenance, backups), which can offset savings for small teams under 50 users.
Can I migrate from Slack to Mattermost without losing data?
Mattermost provides official import tools for Slack workspaces, including message history, users, channels, and files. Migration preserves most data, though some Slack-specific features (workflows, canvas) may require manual reconfiguration. Plan 1-2 weeks for a full enterprise migration with validation.
Why does Slack have 4x more integrations than Mattermost?
Slack's 2,000+ integrations reflect its 15-year market dominance and larger developer ecosystem. Slack has over 750,000 active workspaces incentivizing third-party developers. Mattermost's 500+ integrations cover 90% of enterprise use cases (Jira, GitHub, Salesforce, Microsoft Teams), though niche tools may require custom webhooks.
Which platform is more secure: Mattermost or Slack?
Both are enterprise-grade secure, but differently. Mattermost offers superior data sovereignty (air-gapped, on-premises deployment) ideal for HIPAA/FedRAMP/SOC2 compliance. Slack offers managed infrastructure with automatic updates and penetration testing but relies on cloud trust. For regulated industries (healthcare, government, finance), Mattermost's self-hosted model is preferred; for standard SaaS companies, Slack's managed security is sufficient.
How do Mattermost and Slack compare for team productivity features?
Slack leads with advanced features: AI-powered search, Canvas (collaborative documents), Workflow automation, and 2,000+ integrations enabling complex automation. Mattermost includes core features (channels, threads, mentions, file sharing, basic automation) but requires custom development for advanced workflows. Slack is more feature-rich out-of-the-box; Mattermost requires configuration but allows full customization via plugins.
How to Choose Between Mattermost and Slack
Deployment Model: Mattermost has Self-hosted or cloud (open-source), while Slack has Cloud-only SaaS.
Monthly Cost Per User: Mattermost has $4-8 (self-hosted) or free open-source, while Slack has $8-15.
Third-Party Integrations: Mattermost has 500+ integrations, while Slack has 2,000+ integrations.
Data Ownership: Mattermost has Full control (self-hosted option), while Slack has Slack controls data.
Enterprise Adoption: Mattermost has 50,000+ organizations, while Slack has 750,000+ active workspaces.
Open Source Code: Mattermost has Yes, fully open source, while Slack has Proprietary closed-source.
Message Search Limit: Mattermost has Unlimited (on self-hosted), while Slack has 10,000 most recent messages (free plan).