Statically - The free optimization & CDN for images, CSS, JavaScript, and open source.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
jsDelivr - A free, fast, and reliable Open Source CDN for npm and GitHub with the largest network and best performance from all OSS CDNs. Serving 100 billion requests per month.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
raw.githack.com - raw.githack.com serves raw files from github.com with proper Content-Type headers (like rawgit.
Nagios - Complete monitoring and alerting for servers, switches, applications, and services