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.
Google Payment API - Enable an easy-to-use checkout experience for customers
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Giftcard Zen - Buy a gift card at a discount
Better Uptime - We call you when your website goes down
Wirize - Payment checkout for freelancers