Mattermost review 2026: the open-source Slack alternative for secure, self-hosted team messaging. Compare pricing, features, pros, cons and alternatives.
Researched and fact-checked by Bartu Cavusoglu · Updated July 18, 2026
Mattermost is an open-source alternative to Slack and Microsoft Teams, built for organizations that need full control over where their communication data lives, whether that is a self-hosted server, an air-gapped environment, or Mattermost's managed cloud.
Founded in 2011 by Corey Hulen and Ian Tien and headquartered in Palo Alto, California, Mattermost has built a strong following among software engineering teams, DevOps organizations and government or regulated-industry customers who need secure, self-hostable messaging.
Core messaging features include channels, direct and group messages, voice calls and screen sharing, alongside deep integrations with developer tools like GitHub, GitLab, Jenkins, Jira and ServiceNow via webhooks, slash commands and bots.
Playbooks, Mattermost's workflow automation feature, lets teams build repeatable, checklist-driven processes for incident response, security operations or onboarding, automatically spinning up a dedicated channel with tasks and status tracking when triggered.
The free Starter tier is self-hosted with unlimited users, channels and message history, making it a capable entry point for small teams or evaluation.
Professional costs 10 dollars per user per month billed annually and adds SSO, LDAP sync, MFA and guest accounts, while Enterprise is custom-priced and adds high-availability clustering, compliance exports and 24x7 support, available either self-hosted or via Mattermost Cloud.
Yes, the Starter tier is free and self-hosted with unlimited users, channels and message history. Paid Professional and Enterprise tiers add security, compliance and support features.
Yes, Mattermost can be fully self-hosted, including in air-gapped environments, or run through Mattermost Cloud as a managed service.
Professional costs 10 dollars per user per month, billed annually.
Playbooks is a workflow automation feature for building repeatable, checklist-driven processes like incident response or onboarding, integrated directly with channels.
Mattermost is popular with software engineering and DevOps teams, as well as government, defense and financial-services organizations that need self-hosted or compliant messaging.
Mattermost offers similar core messaging features to Slack but adds open-source self-hosting, air-gapped deployment and built-in workflow automation, targeting security- and compliance-sensitive organizations.