NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.
UptimeRobot - Free Website Uptime Monitoring
Splunk - Splunk's operational intelligence platform helps unearth intelligent insights from machine data.
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.
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.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring