Google Stackdriver Error Reporting - Aggregates and displays errors produced by cloud services
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
Million.js - A fast, <1kb virtual DOM
Hawk - Hawk provides visual user tracking and error reporting with live screen view, deep filtering and robust access control.
Sentry.io - From error tracking to performance monitoring, developers can see what actually matters, solve quicker, and learn continuously about their applications - from the frontend to the backend.
AppSignal - We monitor the software that makes your customers happy.