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.
TestFlight - iOS beta testing on the fly.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
TestApp.io - A platform that helps both mobile app developers and owners to easily share their apps with everyone to get feedback before reaching publicly to Google and App stores.
Better Uptime - We call you when your website goes down
AppHost - Free iOS and Android (IPA and APK) app hosting for enterprise and internal mobile apps.