Is It Down Right Now? - Network & Admin
WrapAPI - Build an API on top of any website
Site Down - Site down outage and downtime reports from SiteDown.co
StatusPage.io - StatusPage.io is the best way for web infrastructure, developer API, and SaaS companies to get set up with their very own status page in minutes. Integrate public metrics and allow your customers to subscribe to be updated automatically.
Is it Down? - Is it down can check if a website is down or is it just your PC that can not access it.
Directus - Free and Open-Source Headless CMS