Its actually already supported, I just don’t think its documented.

go to: <your_ha_server>:8123/dev-service

Set “Domain” to “Notify”

Set “Service” to whatever you named the slack integration

Under “Service Data” do something like

{ "message": "testing", "target": "#notifications", "data": { "attachments": [ { "color": "#36a64f", "pretext": "Optional text that appears above the attachment block", "title": "Slack API Documentation", "title_link": "https://api.slack.com/", "text": "Optional text that appears within the attachment", "fields": [ { "title": "Priority", "value": "High", "short": false } ] } ] }

Basically anything in this doc https://api.slack.com/docs/message-attachments can be nested under “data -> attachments” in your payload I believe.

Note looks like you have to supply the “message” part or it won’t send.