WebGazer is an uptime monitoring platform that checks if your website is up as it should be and notifies you if anything goes wrong
productboard - Beautiful and powerful product management.
UptimeRobot - Free Website Uptime Monitoring
Hassl - A really great project management app
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.
Arbor - Easily manage product development
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring