Platypus - Realtime server monitoring and reporting
Healthy Servers - Making server monitoring easy
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.
Monitornator - Server monitoring made simple
Nagios - Complete monitoring and alerting for servers, switches, applications, and services
Cloud Functions for Firebase - Serverless / Task Processing