Custom Integration

I am using a bash script with curl that does something similar:

local/share/check_mk/notifications/my-custom-notify.sh

#!/bin/bash
# Custom Notify by JSON HTTP
# In the second line after the comment character # is a Title for the script.
# As a rule this will be shown when selecting the notification method.
....

timeout 5 curl \
	--silent \
	--request POST \
	--header 'Content-type: application/json' \
	--data '{"text":'"'$msg'"'}' \
	--connect-timeout 3 \
        "${hook_url}"