LogTailApp - LogTail is a local and remote (SSH) log file viewer and monitoring application for Mac OS X. It is a pure, modern, document-based Cocoa App
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.
Hawk - Hawk provides visual user tracking and error reporting with live screen view, deep filtering and robust access control.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
AppSignal - We monitor the software that makes your customers happy.
Better Uptime - We call you when your website goes down