As @timotree pointed out in a comment you should be able to initiate a call to a “channel” using: <team api url>/call/<channel id>. To automate this, have the call be initiated by a server you own. There you can simply set up a cron job something like 45 10 * * 1-5 <your script> >/dev/null 2>&1 You could use a bash script using a curl request for this, or use the programming language you like.
