Servitor.io VS NetVizura NetFlow Analyzer

Observu - Observu offers website, server and API monitoring solutions.

Zabbix - Track, record, alert and visualize performance and availability of IT resources

Nodeping - NodePing Server Monitoring and Web Site Monitoring. Simple but powerful Internet service monitoring.

Abusix - Abusix is a network security company that offers email threat protection and network abuse handling solutions to ISPs, Telcos, and Cloud/Hosting Providers to stop the rapidly growing problem of email-borne threats and other kinds of network abuse.

NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.

FastNetMon - FastNetMon is a very fast DDoS analyzer with sflow/netflow/mirror support.