Best Self Hosted Alternatives to Mattermost (Cloud)

Rocket.Chat is an open-source communications platform for team messaging and customer engagement. It provides persistent chat (channels and direct messages), collaboration features, and enterprise-grade controls, and can be extended via apps, integrations, and APIs.

Key Features

• Public/private channels, direct messages, threads, reactions, mentions, and file sharing
• Omnichannel inbox for customer support (live chat widget, queueing/routing, agents, transcripts)
• Audio/video meetings and screen sharing (deployment-dependent), plus voice messages
• Federation support (Rocket.Chat Federation) to connect separate Rocket.Chat servers
• Strong administration features: roles/permissions (RBAC), audit logs, retention policies, and compliance tooling (plan-dependent)
• SSO/identity integrations (e.g., SAML/OIDC/LDAP) and granular access controls
• Extensive integrations and automation: webhooks, REST APIs, bots, and a marketplace/app framework
• Multi-platform clients (web, desktop, mobile) and localization support

Use Cases

• Internal team chat for organizations that need control over deployment and data
• Customer support and sales chat using an embedded website live-chat widget
• Cross-organization collaboration via federation between independently operated servers

Limitations and Considerations

• Some advanced security/compliance and omnichannel features may be gated by licensing/plan
• Real-time performance and search depend on sizing and backing services (notably MongoDB)

Rocket.Chat is a mature, widely deployed Slack alternative that combines team chat with customer messaging workflows. It is best suited to organizations that want extensibility, admin controls, and optional omnichannel support in one platform.