Healthchecks is a great service! Not sure if you tried it too but https://cronitor.io/ https://cronitor.io/ supports more complex alerting rules like the one y

Healthchecks is a great service! Not sure if you tried it too but https://cronitor.io/ https://cronitor.io/ supports more complex alerting rules like the one you describe. As a bonus, you can also create uptime checks and status pages under the same roof. Full-disclosure: I work at Cronitor, happy to help if you have any questions :)