Antimatter
Antimatter is an open-source community fork of Mattermost, rebuilt under AGPL and Apache licenses. It removes paywalls, promotional pop-ups, and telemetry features present in the upstream project, and independently implements enterprise-grade authentication capabilities including LDAP, SAML, and OIDC. The project is focused on self-hosted deployment scenarios.
Timeline (last 90 days)
Antimatter is a fork based on Mattermost's open-source code, aiming to provide self-hosted open-source chat software without paywalls or promotional pop-ups.
Antimatter is based entirely on Mattermost's free and open-source code (AGPL / Apache license) and does not touch any of the enterprise edition's closed-source components.
Antimatter rebuilt from scratch features that previously only existed in the enterprise edition, including LDAP, SAML, and OIDC authentication, as well as multilingual translation.
The author removed more than 400 feature-flag conditionals (if branches) in the FOSS code that distinguished between the free and paid versions, deleted all promotional pop-ups, and removed telemetry functionality.
Features planned for Antimatter include voice channels, disappearing messages, a role system with colors, full XMPP-style federation, self-hosted GIF search, and Groupware integration.
Antimatter's code is hosted on GitHub (under the AntimatterChat organization) and a Docker image ghcr.io/antimatterchat/antimatter is provided.
The Antimatter author describes it as a drop-in replacement for Mattermost, and existing users can theoretically migrate smoothly.
The docker compose configuration example provided by Antimatter pairs with a PostgreSQL 17 database; after startup, access it at http://localhost:8065, and the first account created automatically becomes the system administrator.
Antimatter is still in an early stage, and many highlights on the feature roadmap have yet to be implemented.
All Facts (8)
Antimatter is a fork based on Mattermost's open-source code, aiming to provide self-hosted open-source chat software without paywalls or promotional pop-ups.
50%UnverifiedAntimatter is based entirely on Mattermost's free and open-source code (AGPL / Apache license) and does not touch any of the enterprise edition's closed-source components.
50%UnverifiedAntimatter rebuilt from scratch features that previously only existed in the enterprise edition, including LDAP, SAML, and OIDC authentication, as well as multilingual translation.
50%UnverifiedThe author removed more than 400 feature-flag conditionals (if branches) in the FOSS code that distinguished between the free and paid versions, deleted all promotional pop-ups, and removed telemetry functionality.
50%UnverifiedThe Antimatter author describes it as a drop-in replacement for Mattermost, and existing users can theoretically migrate smoothly.
50%UnverifiedThe docker compose configuration example provided by Antimatter pairs with a PostgreSQL 17 database; after startup, access it at http://localhost:8065, and the first account created automatically becomes the system administrator.
50%UnverifiedFeatures planned for Antimatter include voice channels, disappearing messages, a role system with colors, full XMPP-style federation, self-hosted GIF search, and Groupware integration.
50%UnverifiedAntimatter's code is hosted on GitHub (under the AntimatterChat organization) and a Docker image ghcr.io/antimatterchat/antimatter is provided.
50%