Mattermost is an open-core collaboration platform for channels, direct messages, files and technical workflows. It can be self-hosted and connected to other tools through APIs, webhooks and integrations. The commercial editions add administration, automation and support features beyond the open-source foundation.
The free Entry mode limits visible and searchable channel history to 10,000 messages across the server. Team Edition is a separate free open-source offering intended for small teams without SSO requirements. Professional, Enterprise and Enterprise Advanced have different capabilities; self-hosting alone does not include every enterprise feature.
Sources: Plans · Product overview
