I only run 2 docker containers in a server, so I don't need anything complex.
I couldn't really fine a simple alerting tool, so I wrote a script that periodically checks if my docker containers are alive or not, and ping me on Telegram if one of them dies.
Maybe I'm a little too inexperienced to understand how this works - how does your app access Mailchimp without their permission? Are you using their API? Sorry if it's a silly question