WebGazer is an uptime monitoring platform that checks if your website is up as it should be and notifies you if anything goes wrong
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.
UptimeRobot - Free Website Uptime Monitoring
Uilicious Snippet - Free testing platform to replicate & share website bugs 🐞
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
DocRaptor - As the only API powered by the Prince HTML-to-PDF engine, DocRaptor provides the best support for complex PDFs with powerful support for headers, page breaks, page numbers, flexbox, watermarks, accessible PDFs, and much more
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.