Churnzero - ChurnZero is the Customer Success Platform built for growing SaaS and subscription businesses.
StatusOk (Open source) - Get notified through Slack/email when your website is down
Totango - Totango is a Customer Success Software Platform
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
Gainsight - Customer Success for the New Enterprise
Get Notified - Get Notified when something happens