Uptime & SSL Monitoring
"PingPing checks your websites and SSL certificates and will notify you when websites are down or certificates become invalid. PingPing offers 30-seconds checks for all your websites. We offer a free plan which allows you to monitor 2 websites.
Everything from PingPing runs on Laravel and Horizon. We use Horizon to process around 75k jobs every 5 minutes to perform all the uptime and SSL checks for all the websites we monitor."