UptimeRobot - Free Website Uptime Monitoring
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Netformx - Netformx helps Cisco partners & Solution Providers deliver multi-vendor IT solutions quickly & effectively while improving profitability & customer success.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Super Monitoring - Affordable uptime monitoring service for webmasters and website owners. Have your website or server checked every minute and get alerted instantly.
Dynatrace - Cloud-based quality testing, performance monitoring and analytics for mobile apps and websites. Get started with Keynote today!