Overview of Slack and Mattermost
Slack and Mattermost are leading platforms for enterprise messaging, but differ fundamentally in deployment and flexibility. Slack is a cloud-based solution with widespread adoption and an extensive integrations ecosystem. Mattermost, by contrast, is open source and can be self-hosted, giving organizations direct control over security and compliance. These differences shape their usefulness for various business needs, from rapid deployment to highly regulated sectors demanding data sovereignty.
- Slack is fully managed in the cloud, requiring no infrastructure overhead for you.
- Mattermost’s open-source, self-hosted model puts customization, control, and privacy at the forefront.
- Both support enterprise-grade messaging, authentication, compliance, and integrations, but through different models.
Key Takeaways
- Slack offers extensive integrations and turnkey cloud deployment, making it accessible and easy to use for teams of all sizes.
- Mattermost stands out for open-source code and self-hosted deployment, ideal when compliance, privacy, or customizability are top priorities.
- Slack’s free version limits message history and integrations, while Mattermost’s free self-hosted plan is less restricted.
- Security and compliance align with enterprise needs on both platforms, though the method—cloud-managed or self-controlled—differs.
| Feature | How Slack handles it | How Mattermost handles it | Best for |
|---|---|---|---|
| Deployment | Fully cloud-hosted, no self-hosting. | Open-source, can be self-hosted or cloud. | Slack: Fast setup; Mattermost: Customizable hosting |
| Pricing | Free plan; paid tiers start at $7.25/user/mo. | Self-hosted core is free; cloud/enterprise from $10/user/mo. | Slack: Simpler budgeting; Mattermost: Cost control at scale |
| Message History | Free plan: 90-day message history limit. | No limit (self-hosted free version). | Mattermost: Record-keeping; Slack: Light users |
| Integrations | Many built-in; market leader in ecosystem. | Open API; built-in and custom integrations (plan-dependent). | Slack: Out-of-box apps; Mattermost: Custom setups |
| Authentication | SSO/MFA on paid plans. | SAML, OAuth; E2EE in some setups. | Both: Enterprise auth; Mattermost: More options |
| Compliance | SOC 2, GDPR (paid plans), data encryption. | HIPAA, GDPR, FINRA feasible with self-hosting. | Mattermost: High control; Slack: Simpler compliance |
| API Access | Supported; details per plan. | Open REST API with full access (core version). | Mattermost: Custom automation |
| Data Retention | Managed via admin controls (paid). | Full control (self-hosted). | Mattermost: Regulatory needs |
Pricing and Plan Structures
Slack offers a free plan with basic features, 90-day message retention, and up to 10 external integrations. Paid plans currently start at $7.25 per user per month (2024), unlocking longer message retention, more integrations, advanced security, and compliance options.
Mattermost’s core open-source version is free and can be self-hosted, including most core features without artificial message or user limits. Paid plans begin at $10 per user per month, primarily for advanced integrations, compliance, support, or fully managed cloud hosting. Organizations that need to customize software or run it in private environments avoid recurring SaaS fees with Mattermost self-hosting.
Message History and Data Access
On Slack’s free plan, you can only access the most recent 90 days of messages—older conversations are hidden until you upgrade. This can be a drawback for teams needing historical records for legal, compliance, or audit purposes. Paid plans remove this cap, letting admins define custom retention rules.
Mattermost’s self-hosted free version keeps your entire message history accessible by default, helping maintain full audit trails without an upgrade. You get direct access to your own data, which is especially useful for regulated industries or those with in-house IT resources.
Integrations and Customization
Slack is renowned for its breadth of built-in integrations—its marketplace covers most popular business apps. This out-of-the-box compatibility means you can quickly automate workflows and connect tools without custom coding.
Mattermost offers an open API and supports integrations as well, although the range and ease of setup is less than with Slack by default. With self-hosting, technical teams can build custom integrations, connect internal apps, and use APIs to extend functionality, but some advanced options require a paid plan.
Deployment Options: Cloud vs. Self-Hosting
Slack is cloud-only; you cannot deploy it in your own environment. The strength here is in rapid deployment, low admin effort, and professionally managed infrastructure. However, this may not meet requirements in highly regulated sectors or where local data residency is mandated.
Mattermost can be fully self-hosted on your hardware or private cloud, giving unmatched control over infrastructure, from data storage to network access. Organizations with strict privacy, compliance, or localization needs often favor this model, especially since the base edition is open source. Managed cloud hosting is also available for organizations that prefer not to handle their own deployments.
Security, Compliance, and Privacy
Slack offers enterprise-grade security, including SSO, encryption, and compliance alignment with standards such as SOC 2 and GDPR on paid plans. Security controls and audit tools suit a wide range of organizations, but ultimate data control remains with the vendor.
Mattermost provides flexibility through on-premise/self-hosted architecture for controlling data and compliance boundaries. It supports SAML, OAuth, and can offer end-to-end encryption in certain deployments. With correct setup, Mattermost can help organizations meet higher-stakes requirements like HIPAA and FINRA—though compliance readiness is partly your responsibility as the operator.
Authentication and Data Retention
Slack’s authentication options include SSO and MFA, primarily on paid plans. Data retention is configurable for paid customers, aligning with internal policies and regional laws.
Mattermost supports enterprise authentication options such as SAML and OAuth as standard even in core self-hosted. Retention management is entirely under your control, allowing for strict data governance or custom purging as needed. End-to-end encryption is possible depending on your deployment choices.
Use Cases and Decision Factors
You’ll get quick value from Slack if you:
- Need a feature-rich, hosted messaging tool with a wide integration library and minimal setup.
- Want rapid employee onboarding and proven reliability without infrastructure overhead.
- Prefer company-managed compliance and support for SOC 2 and GDPR out of the box.
Mattermost is often the better choice when:
- Your organization needs full control over hosting, customization, or compliance boundaries—like government, defense, or regulated industries.
- You want open-source software for extensibility, source transparency, or to avoid vendor lock-in.
- Message history and data retention cannot be restricted or must be managed on-premises for regulatory reasons.
When to Choose Slack vs Mattermost
Choose Slack if your main priorities are ease of use, rich app integrations, and managed cloud services. Slack is ideal for businesses that want reliability without the expense or complexity of self-hosting or software maintenance.
Choose Mattermost if control, privacy, regulatory compliance, or code-level customizability are more important than having a vast integrations marketplace or instant cloud deployment. Mattermost makes sense for organizations with a capable IT staff and strict data requirements.
Conclusion
Both Slack and Mattermost excel as enterprise messaging platforms but target different needs. Slack’s strengths are in user experience and plug-and-play integrations, while Mattermost offers open-source freedom, self-hosting, and robust compliance control. Your choice depends less on messaging basics and more on IT resources, regulatory demands, and how much you value control versus convenience.
Which is better for enterprise use, Slack or Mattermost?
If ease of management and a rich integrations library matter most, Slack is better. If you require open-source, self-hosting, or strict compliance, Mattermost excels.
Does Mattermost offer open-source deployment options compared to Slack?
Yes—Mattermost’s core version is open source and can be self-hosted, while Slack is cloud-only and proprietary.
How do the security and compliance features of Slack and Mattermost compare?
Slack offers compliance with SOC 2 and GDPR (on paid plans). Mattermost enables greater control and meets stricter requirements like HIPAA with proper setup, but the responsibility falls more on you.
What are the main integration differences between Slack and Mattermost?
Slack has a larger marketplace of built-in integrations. Mattermost allows custom integrations and APIs but with more setup required.
Which platform provides better value for money: Slack or Mattermost?
Mattermost’s self-hosted plan can be more cost-effective at scale or for long-term use, but requires IT investment. Slack has simpler pricing and less maintenance overhead.
Can Mattermost match Slack’s user experience and scalability?
Not publicly specified in current evidence. Mattermost is highly customizable but may require more setup for similar usability and scale.
What are the biggest drawbacks of switching from Slack to Mattermost?
You may lose access to Slack’s out-of-the-box integrations, established user experience, and managed cloud services. Mattermost also requires more technical resources to deploy and maintain.