alt Hacker NewsSecurityBot.dev is an all-in-one uptime, performance, security, and SEO monitoring tool. I launched it a few months ago and have been iterating on it ever since. Later this week SecurityBot.dev will log its 1 millionth uptime check which is pretty cool to see.
It includes the usual uptime monitoring service that you see everywhere else, but also features such as a PageSpeed Insights monitor (https://securitybot.dev/pagespeed-insights) and a broken link checker (https://securitybot.dev/broken-link-checker). I continue adding new monitor types as I personally need them (and also based on use feedback).