StatusPage.io - StatusPage.io is the best way for web infrastructure, developer API, and SaaS companies to get set up with their very own status page in minutes. Integrate public metrics and allow your customers to subscribe to be updated automatically.
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.
404 Illustrations - Open-source catchy illustrations for perfect error pages
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
500 error - Your server can crash anytime. Don't miss important leads!
Better Uptime - We call you when your website goes down