What Mattermost receives
Every new finding can go to this channel according to your alert rules: minimum severity, finding types, specific rules, projects. Only new findings are notified; a known, reopened or resolved finding generates nothing. Messages are written in English. The channel can be tested from the application with a fictitious event.
How to connect it
In “Settings”, “Integrations” tab, “Notifications” sub-tab, add the channel with its incoming connector address. Then, in the “Notifications” tab, create an alert rule targeting it. System events (service, scan failure), end-of-scan and assistant summary events only go out if you tick them explicitly.
For Mattermost, you provide the incoming webhook address. A private or internal address is refused: the server must be publicly reachable by your instance.