PagerDuty

PagerDuty generates phone call and SMS alerts from any monitoring software that sends emails, including Nagios. Simply configure Nagios to forward a copy of its alert emails to a PagerDuty provided email address.

Features:
* Graphical creation of on-call schedules.
* Multi-level escalation chains with both automatic escalation after a timeout and manual escalation.
* Customized per-user notification sequences. Each user can receive alerts using any combination of phone calls, SMSes, and emails.
* Alarms can be suppressed, escalated, or resolved directly from the phone. No need to pull out a laptop if an alert comes in at a bad time.
* Full incident logging shows all actions taken in response to an alarm.
* Email based triggering supports integration with nearly all monitoring systems. Allows for centralized alert management across all of your monitoring tools.
* Regex email filtering ensures alarms are only triggered when appropriate.