Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Circonus - Circonus combines multiple monitoring, alerting, event processing, and analytics tools into one unified solution.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
10Duke Enterprise - Powerful cloud-based licensing solution designed for fast-growing software businesses looking to scale up software licensing & minimize friction.
Better Uptime - We call you when your website goes down
pgBadger - pgBadger is a PostgreSQL log analyzer.