UptimeRobot - Free Website Uptime Monitoring
Incapsula DDoS - Incapsula DDoS is a platform that comes with multiple DDoS protection options and mitigates attacks without incurring latency.
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
StackPath Web Application Firewall - StackPath Web Application Firewall is a cloud-delivered security service that provides layered security for web applications that is based on the best practices of Enterprise Security.
UptimeRobot App - Web, SSL, ports & Cron-jobs monitoring
Arbor DDoS - Arbor DDoS is a platform which helps the users in understanding their environments along with their threat actors and delivers powerful visibility and traffic intelligence at internet scale.