Lowdown - Lowdown unleashes the valuable content locked within Slack and emails it to your members so they don't miss key information.
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.
Scrumbot - A summary of all team data in Slack before your daily scrum
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Marketplace Hacks - A slack community of marketplace founders & operators
Better Uptime - We call you when your website goes down