I have built a slack slash command which is up and running and which currently displays an image using an attachment (https://api.slack.com/docs/message-attachments). Instead of an image, I'd like it to have an audio player. It does not need to be my custom audio player, it can be a simple play button but it should be playable within slack. Is there a way to provide the URL to an audio file and let slack show a player (like for images)?
I contacted the Slack devs support and they confirmed that what I'm trying to do is not possible. They only support playing files within the Slack conversation from some 3rd party service integrations. Too bad :S