Slack API message.im event is not triggered for other users

Question

I am trying to make my app watch for every kind of messages (public/private channels and direct messages) using event subscriptions, no bot. I made my app subscribe to mes

Answer 1

It is not supposed to work. Even if you subscribe to "Workspace Events" you should only be able to see messages of conversations that the user that installed the Slack app is invited in. Including private channels and IM.

I just tested this on my Slack. Installed the Slack app with an owner user, but still can only see messages from private channels, that that user is a member of.

So this works "as designed" and according to the security architecture of Slack.