Healthchecks.io - Monitor your cron jobs and scheduled tasks, get notified when they fail.
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.
Pingbreak - Pingbreak is an original and free monitoring service.
Hosted Status Page - Incident Management with Automated Downtime Detection
DownDetector - A simple service to tell you whether a website is down.
Status.io - Status.io is a platform for system status pages and status notifications. Companies rely on Status.io to track outages, schedule planned maintenances, broadcast status notifications, and much more; and their customers love the transparency.