Squadcast - Automate incident response, reduce downtime and enhance your tech teams’ delivery with a unified platform.
One Call Now - One Call Now's message notification delivers automated phone calls, SMS text messages and emails within moments to any group.
PagerDuty - Cloud based monitoring service
DeskAlerts - Send alerts to any corporate device: PCs, phones, tablets, etc.
OpsGenie - Alerting and On-Call Management for Dev&Ops Teams
Sweet Alert - Sweet Alert is a replacement for Javascipt's "Alert".