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.
Memory Cleaner - Memory optimization and monitoring solution for Mac.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Dr. Cleaner - Dr. Cleaner for Mac helps you keep your computer running smoothly by removing unwanted files and optimizing your available memory. It also works quickly, so
Better Uptime - We call you when your website goes down
CleanMem - CleanMem keeps memory use in check on the system without the memory being pushed to the page file.