PagerDuty - Cloud based monitoring service
One Call Now - One Call Now's message notification delivers automated phone calls, SMS text messages and emails within moments to any group.
VictorOps - We make on-call suck less & help teams to solve problems faster.
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.
Notifuse - A 1-to-many notification API that's simple to use
xMatters - xMatters transforms event data into intelligent communication IT teams, avoiding outages and disruptions