Mattermost

Prerequisites

1. Enable Outgoing Webhooks in Mattermost System Console → Integrations.
2. Create a Bot Account → obtain a Bot Token.
3. Configure Outgoing Webhook to target https://<your-public-host>/mattermost and copy its Token.

Environment

export MATTERMOST_SERVER_URL=https://mattermost.example.com
export MATTERMOST_BOT_TOKEN=...
export MATTERMOST_WEBHOOK_TOKEN=...
export MATTERMOST_WEBHOOK_HOST=0.0.0.0
export MATTERMOST_WEBHOOK_PORT=16671
export MATTERMOST_WEBHOOK_PATH=/mattermost

Thread semantics

Mattermost root_id is thread key (the root message ID of a thread).

Troubleshooting

• Bot can’t post: ensure the Bot Account has been invited to the target channel.
• 413 on upload: Mattermost limits file size to 50 MB by default; raise it in System Console → File Storage.