Octopus mini alternatives

PingPing is a simple to use website and certificate monitoring service. Get notified by the simplest uptime monitoring service in the world, when your website is down or your certificate becomes invalid. No more, no less.

Nodeify allows you to keep track of and monitor any website's SSL certificate. When you register and add a domain into monitoring the app will alert you, based on the notifications you setup, of any updates, issues, and/or upcoming expirations.