Mattermost

Connect DevHelm to Mattermost to receive incident notifications in your team channels. DevHelm posts to a Mattermost incoming webhook, so it works with both self-hosted and Mattermost Cloud instances.

Setup

Create a Mattermost incoming webhook

In Mattermost, open Main Menu → Integrations → Incoming Webhooks
Click Add Incoming Webhook
Choose a display name (e.g., “DevHelm”) and a default channel
Click Save and copy the generated webhook URL (e.g., https://mattermost.example.com/hooks/xxxxxxxxxxxx)

If you don’t see Incoming Webhooks, an administrator must enable them in System Console → Integrations → Integration Management.

Create the alert channel in DevHelm

devhelm alert-channels create \
  --name "Mattermost Alerts" \
  --type mattermost \
  --config '{"channelType":"mattermost","webhookUrl":"https://mattermost.example.com/hooks/xxxxxxxxxxxx"}'

alertChannels:
  - name: Mattermost Alerts
    config:
      channelType: mattermost
      webhookUrl: ${MATTERMOST_WEBHOOK_URL}
      channel: incidents
      iconUrl: https://example.com/devhelm-icon.png

Test the channel

devhelm alert-channels test <channel-id>

Configuration

Field	Description	Required
`webhookUrl`	Mattermost incoming webhook URL	Yes
`channel`	Override the webhook’s default channel (e.g. `incidents` or `@username`)	No
`iconUrl`	Publicly accessible URL for a custom bot icon	No

Channel and icon overrides

channel and iconUrl only take effect if your Mattermost server permits webhook overrides. Enable System Console → Integrations → Integration Management → Enable integrations to override usernames and override profile picture icons. The iconUrl must be reachable from your Mattermost server — relative paths or internal-only URLs are ignored.

Troubleshooting

Webhook disabled or returns HTTP 403

Incoming webhooks can be turned off per-server. Confirm an administrator has enabled System Console → Integrations → Integration Management → Enable Incoming Webhooks, and that the webhook itself hasn’t been deleted under Integrations → Incoming Webhooks.

Channel override has no effect

The webhook posts to its configured default channel unless the server allows overrides. Enable Enable integrations to override usernames and icons in the System Console, then re-run devhelm alert-channels test <channel-id>.

Self-hosted server with a self-signed certificate

DevHelm requires a valid TLS certificate for the webhook host. Install a certificate from a trusted CA (e.g. Let’s Encrypt) on your Mattermost instance — self-signed certificates are rejected during delivery.

Overview

Alert Channels

CI/CD

Setup

Configuration

Channel and icon overrides

Troubleshooting

​Setup

​Configuration

​Channel and icon overrides

​Troubleshooting

Setup

Configuration

Channel and icon overrides

Troubleshooting