Compare / Mattermost vs Rocket.Chat
Mattermost vs Rocket.Chat
Pick Rocket.Chat if you are leaving Slack (the published Slack stack). Pick Mattermost if you are leaving Microsoft Teams (playbooks and calls) — /stacks/mattermost-teams.
Facts checked 17 Oct 2026. License, language, and GitHub activity come from the catalog or the project's own repo. "Not in the catalog row" means the public catalog dump does not store that number.
Mattermost in the catalog Rocket.Chat in the catalogStart on Railway
How they compare
| Mattermost | Rocket.Chat | |
|---|---|---|
| License | AGPLv3 source; compiled binaries MIT; commercial option (LICENSE.txt) source | Open-source workspace chat (catalog row does not list a license) source |
| Language | TypeScript (catalog) | Not listed in the catalog row |
| GitHub activity | 39,359 stars in the catalog source | Star count is not listed in the catalog source |
| Self-host | Postgres + volume. Published as /stacks/mattermost-teams. | Mongo + uploads. Published as /stacks/rocket-chat. |
| Best for | Chat, playbooks, and calls — the Teams off-ramp. | Channels, DMs, and files — the Slack off-ramp. |
Self-hosting and resource needs
Rocket.Chat is /stacks/rocket-chat: persist Mongo/uploads, set ROOT_URL. Mattermost is /stacks/mattermost-teams: Postgres + a volume, set SiteURL. Mattermost source is AGPLv3 (compiled binaries ship under MIT; commercial license available). Neither has a one-click c17 Railway template yet.
FAQ
- Why two stacks?
- /replace/slack is Rocket.Chat only. /replace/microsoft-teams is Mattermost first. Same chat job, different vendor you are leaving. That is the Mattermost stack FAQ.
- What about Zulip?
- See /compare/zulip-vs-mattermost if you want topic threads instead of channels.
- Are these free?
- Mattermost source is AGPLv3. Rocket.Chat is the catalog product. You pay hosting.
- How do I deploy it?
- Open /stacks/rocket-chat or /stacks/mattermost-teams. Persist the database and set the public URL.
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