Slack is a cloud-based SaaS platform owned by Salesforce with extensive integrations and AI features, while Mattermost is a self-hosted open-source alternative offering greater control and lower costs for privacy-conscious organizations. Slack excels in ease-of-use and ecosystem, while Mattermost provides deployment flexibility and data sovereignty.
Mattermost vs Slack — Side-by-side comparison on A Versus B
Open-source, self-hosted team collaboration platform with enterprise security controls
Cloud-based team messaging platform with deep enterprise integrations and 21 million daily active users.
Deployment Model. Pricing Model. Data Ownership & Control. AI Features & Integration. Ease of Setup. Third-party Integrations. User Interface & Experience. Enterprise Security Compliance
Slack is the superior choice for most organizations seeking an easy-to-use, feature-rich communication platform with extensive integrations and AI capabilities. Mattermost is ideal for enterprises prioritizing data sovereignty, cost control, and regulatory compliance where self-hosting is acceptable. The choice depends on whether you prioritize convenience and ecosystem (Slack) or control and cost (Mattermost).
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: Self-hosted, cloud, or hybrid | Slack: N/A
Mattermost: Open-source (Apache 2.0) | 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: 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: $8.25 (Pro plan, min 3 users)
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: 2000+ integrations
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: Proprietary (closed-source)
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, HIPAA, FedRAMP, GDPR
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)
How to choose between Mattermost and Slack
Mattermost vs Slack — Structured Comparison Data
Machine-readable comparison dataset for Mattermost vs Slack. Contains 167 attribute comparisons, 5 FAQ pairs.
Mattermost vs Slack — Attribute Category Vocabulary
Taxonomy of attribute categories used to classify comparison data for Mattermost vs Slack.
How do these platforms handle team growth and scalability?
Slack automatically scales with cloud infrastructure, supporting unlimited growth without infrastructure concerns. Mattermost requires proper server sizing and administration but offers unlimited users with single deployment. For organizations expecting rapid growth, Slack's automated scaling is advantageous, while Mattermost's unlimited-user model benefits predictable enterprise expansion.
Which platform is more cost-effective for large enterprises?
Mattermost is significantly more cost-effective for large organizations. While Slack's Pro tier costs $7.25/user/month, Mattermost's Professional plan is $10/user/month but includes unlimited team members and channels. For organizations with 500+ users, self-hosting Mattermost can reduce costs by 40-60% compared to Slack's per-seat pricing model.
Yes, migration is possible but requires technical effort. Mattermost provides import tools for Slack data including messages, channels, and user information. However, integrations must be reconfigured separately. Many organizations use migration tools from third-party providers to streamline the process. Full migration typically takes 2-4 weeks depending on workspace size.
Is Slack secure for regulated industries?
Slack meets compliance standards including SOC 2, HIPAA, and GDPR, making it suitable for regulated industries. However, data remains on Salesforce's infrastructure. For organizations with strict data residency requirements (requiring data stored in-country), Mattermost's self-hosting option provides greater control and compliance flexibility.
What are the main productivity differences between these platforms?
Slack excels in productivity through its vast integration ecosystem (2000+ apps), advanced AI assistant for search and automation, and polished user experience that requires minimal training. Mattermost provides solid collaboration features but with fewer native integrations. For teams heavily reliant on third-party tools, Slack typically offers superior workflow automation and efficiency.
How to Choose Between Mattermost and Slack
Deployment Model: Mattermost has Self-hosted, on-premise, or cloud options, while Slack has Cloud-based SaaS only.
Pricing Model: Mattermost has Open-source free tier + $10/user/month (Pro), while Slack has $7.25/user/month (Pro) + Enterprise Grid.
Data Ownership & Control: Mattermost has Full control with self-hosting, data sovereignty, while Slack has Salesforce controls infrastructure and data.
AI Features & Integration: Mattermost has Limited native AI, basic automation, while Slack has Advanced AI assistant, extensive integrations.
Ease of Setup: Mattermost has Requires technical expertise for deployment, while Slack has Instant setup, no installation needed.
Third-party Integrations: Mattermost has 500+ integrations available, while Slack has 2000+ integrations and app ecosystem.
User Interface & Experience: Mattermost has Functional but less polished interface, while Slack has Intuitive, modern, user-friendly design.
Consider: Enterprise Security Compliance
Enterprise Security Compliance: Mattermost has SOC 2, HIPAA, GDPR compliant (self-hosted), while Slack has SOC 2, HIPAA, GDPR, FedRAMP compliant.