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.
Clearbit - Clearbit provides Business Intelligence APIs
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Amobee DSP - Cross-Channel Advertising
Better Uptime - We call you when your website goes down
DataXu - Marketing analytics for brands and agencies.