Infoblox - Infoblox is a development platform that offers multiple services.
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Apica.io - Limitless Data, Control and Insights
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Better Uptime - We call you when your website goes down
WebSitePulse - WebSitePulse monitoring service. Test your site and server. Design your own monitoring service.