Sitewatch

Sitewatch monitors whether your website actually works, not just whether it responds. Most uptime tools check if your server returns 200 OK, but your site can return 200 while serving broken JavaScript, wrong MIME types, redirect loops, or stale cached content, resulting in a blank page while your monitoring says everything is fine.

Sitewatch goes deeper by verifying that critical assets load correctly, following redirect chains to completion, fingerprinting content to detect silent changes, and checking from multiple regions. When something breaks, it identifies the root cause and tells you how to fix it for your specific tech stack. Free for one site.