Mattermost and Rocket.Chat are both open-core, self-hostable team chat platforms with unpublished enterprise pricing, but they emphasize different things.…
Best for Mattermost: Mattermost fits teams that want built-in incident-response workflow automation (Playbooks) and Kanban-style project boards alongside chat, especially regulated organizations needing FIPS 140-3/STIG-hardened images.
Best for Rocket.Chat: Rocket.Chat fits teams needing the broadest published compliance certification list — SOC 2, ISO 27001, GDPR, HIPAA, and DoD ATO up to IL6 — or cross-organization federation, including government and defense deployments.
At a Glance
Mattermost
Rocket.Chat
Primary category
Team Chat
Team Chat
Rating
Not documented
Not documented
Pricing model
Freemium
Freemium (free self-hosted Community edition, plus paid Pro and Enterprise plans)
Starting price
Free (Starter, self-hosted); Professional from $10/user/month
Free (Community); Pro from $8/user/month billed annually
Free plan
Yes
Yes
Free trial
Not documented
Not documented
Platforms
Web, iOS, Android, Mac, Windows
Web, iOS, Android, Mac, Windows
Team collaboration
Not documented
Not documented
AI features
Not documented
Not documented
Public API
Not documented
Yes
Key Differences
Licensing Model
Mattermost: Mattermost is open-core: a compiled edition is released monthly under MIT, with separately licensed enterprise features on top (38.5k GitHub stars).
Rocket.Chat: Rocket.Chat is fully MIT-licensed with 45.8k GitHub stars.
A fully open-source license avoids feature gating tied to a separate enterprise license.
Compliance Certifications
Mattermost: Mattermost documents FIPS 140-3 compliance and STIG-hardened images on its Enterprise Advanced tier; SOC 2/ISO 27001/HIPAA certification isn't documented in the facts.
Rocket.Chat: Rocket.Chat documents SOC 2, ISO/IEC 27001, GDPR, HIPAA, and DoD ATO up to IL6.
Regulated industries need to match specific certification requirements before adopting a platform.
Built-in Workflow & Project Tools
Mattermost: Mattermost includes Playbooks (workflow automation for incident response) and Kanban boards built into the platform.
Rocket.Chat: Rocket.Chat offers an Apps-Engine for building custom apps and integrations, but no built-in Kanban or Playbooks-style workflow feature is documented.
Built-in workflow tools reduce the need for separate incident-response or project-tracking software.
AI Features
Mattermost: Mattermost's Enterprise tier adds 'Sovereign AI and contextual summarization,' plus AI summarization on recorded audio calls.
Rocket.Chat: Rocket.Chat has no AI feature documented in the facts.
AI summarization can reduce time spent catching up on missed discussions and calls.
Federation
Mattermost: Mattermost documents Microsoft Teams interoperability (shared channels) on Enterprise plans, not a native federation feature.
Rocket.Chat: Rocket.Chat documents Federation as a native feature for communicating across separate Rocket.Chat organizations.
Federation lets separate organizations communicate without merging into one workspace.
Feature-by-Feature
Deployment & Licensing
Feature
Mattermost
Rocket.Chat
Self-hosted free edition
Available
Available
Air-gapped deployment
Available
Available
Fully open-source (no open-core split)
Limited
Available
Public cloud deployment (AWS/Azure/GCP)
Available
Not documented
Collaboration Features
Feature
Mattermost
Rocket.Chat
Built-in workflow automation/playbooks
Available
Not documented
Kanban boards
Available
Not documented
Federation across separate organizations
Not documented
Available
Built-in video calling
Not documented
Available
Compliance & Enterprise
Feature
Mattermost
Rocket.Chat
FIPS 140-3 compliance
Available
Not documented
SOC 2 / ISO 27001 / HIPAA certification
Not documented
Available
DoD Authorization to Operate
Not documented
Available
Microsoft Teams interoperability
Available
Not documented
Pricing Compared
Starting price reflects the lowest paid tier, not the full cost for every team size or usage level.
Mattermost
Starter — Free N/A
Professional — $10/user/month annual
Enterprise — Custom annual
Rocket.Chat
Community — Free N/A
Pro — $8/user/month annual
Enterprise / Government / Defense — Custom custom
Pros & Cons
Mattermost
Pros
Fully open-source core with self-hosted and air-gapped deployment options
Strong fit for regulated industries, government and defense customers
Playbooks provide built-in workflow automation not native to Slack
Deep integrations with developer and DevOps tooling
Lightweight architecture (single Go binary) makes self-hosting comparatively simple
Cons
Smaller app/integration marketplace than Slack or Microsoft Teams
Enterprise pricing is custom-quoted and not publicly transparent
Self-hosting requires ongoing server maintenance and updates
UI and mobile experience is generally considered less polished than Slack
Annual prepaid billing only for official Professional and Enterprise licenses, no monthly option
Rocket.Chat
Pros
Free, self-hosted Community edition with no user-count-based licensing cost beyond infrastructure
Full source code access supports auditing and customization
Flexible deployment options including air-gapped and sovereign cloud for regulated industries
Combines internal team chat and customer-facing omnichannel support in one platform
Cons
Self-hosting requires infrastructure management and technical expertise the hosted competitors don't demand
Enterprise, Government, and Defense pricing is not published and requires a sales conversation
Community edition caps out at fifty users before requiring a paid plan
UI and performance can lag behind polished proprietary competitors like Slack for casual users
Use Cases
Choose Mattermost: Mattermost fits teams that want built-in incident-response workflow automation (Playbooks) and Kanban-style project boards alongside chat, especially regulated organizations needing FIPS 140-3/STIG-hardened images.
Choose Rocket.Chat: Rocket.Chat fits teams needing the broadest published compliance certification list — SOC 2, ISO 27001, GDPR, HIPAA, and DoD ATO up to IL6 — or cross-organization federation, including government and defense deployments.
Need both: There's little realistic scenario for running both in production for the same team — both are alternative self-hosted chat platforms serving the same core communication need, so an organization would typically pilot one against the other during evaluation rather than deploy both as its primary chat tool.
Mattermost
Incident response and DevOps workflows — Engineering teams use Playbooks to coordinate incident response with automated checklists and dedicated channels.
Regulated and government communication — Public-sector and financial-services organizations need self-hosted or air-gapped messaging to meet compliance requirements.
Secure internal team chat — Organizations that want Slack-like messaging while keeping full control of where data is stored.
Rocket.Chat
Privacy-focused team messaging — Organizations that need to keep chat data within their own infrastructure self-host Rocket.Chat's Community edition.
Regulated government and defense communication — Public-sector and defense organizations use Rocket.Chat's air-gapped and sovereign cloud deployment options for secure communication.
Combined internal and customer chat — Businesses use Rocket.Chat for both internal team collaboration and customer-facing omnichannel support in a single platform.
Frequently Asked Questions
Is Mattermost fully open source?
It's open-core: a compiled edition is released monthly under the MIT license, with separately licensed enterprise features layered on top.
Is Rocket.Chat fully open source?
Yes, Rocket.Chat is open source under the MIT license.
Which tool has published compliance certifications?
Rocket.Chat documents SOC 2, ISO/IEC 27001, GDPR, HIPAA, and DoD ATO up to IL6. Mattermost documents FIPS 140-3 compliance and STIG-hardened images but not the same certification list.
Does either tool publish pricing for paid plans?
No. Both Mattermost's Professional/Enterprise/Enterprise Advanced tiers and Rocket.Chat's Commercial/Government/Defense plans require contacting sales for pricing.
Which tool includes built-in workflow automation?
Mattermost, via its Playbooks feature for automating recurring workflows and incident response.
Does either support government or defense deployments?
Rocket.Chat has a dedicated Defense plan with DoD ATO up to IL6. Mattermost's Enterprise Advanced tier supports air-gapped and classified deployments but doesn't document a specific DoD ATO rating.