It can be the bane of a SysAdmin or software engineer's world: those late night notices that a server's crashed, that a key process is suddenly returning critical errors. Even worse, arguably, is a lack of notifications. Then you get in to work on Monday to find that the person on call "didn't get the message" and things have been broken since 5:01 Friday night.
PagerDuty also sends notifications when things go awry. But the service doesn't just send emails and hope that someone will notice and fix things. With PagerDuty, you can configure your notification chain, sending emails and texts to the right people. And if they don't respond, the issue can be escalated, again to the right person.
PagerDuty works with email notifications but also offers an API, which makes it easy to integrate PagerDuty with other services. Crashing servers aside, Alex Solomon, PagerDuty's CEO and founder, told me today that there's a municipality in Canada that uses PagerDuty's API to monitor ice on the roads.
As Canadian-ice-alerts suggests, PagerDuty offers international notifications. There's a 30-day free trial for the service, and monthly fees depend on how many users in your team.