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.
Quick License Manager - Quick License Manager (QLM) is a license protection framework that creates professional and secure license keys to protect software against piracy.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Labs64 NetLicensing - Monetize your digital products and services
Better Uptime - We call you when your website goes down
LicenseSpring - Reliable and easy to use License-As-A-Service (LaaS) for for any software application