Skype for Slack - Move your slack discussions to a group skype call
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.
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Slack - A messaging app for teams who see through the Earth!
Better Uptime - We call you when your website goes down