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.
WebFaction - Hosting for developers: full shell access to fast servers with all your favorite tools pre-installed and maintained for you.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
AceCloudHosting QuickBooks Hosting - Future-Proof Your Business with ACE Cloud and Security Synergy
Better Uptime - We call you when your website goes down
ServerPilot.io - Centralized hosting control panel for Wordpress and PHP web sites