What are some alternatives?
Zabbix - Track, record, alert and visualize performance and availability of IT resources
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.
Nagios - Complete monitoring and alerting for servers, switches, applications, and services
Site24x7 - Site24x7 offers both free & paid website monitoring services. Monitor websites remotely and receive instant email/sms alerts if your website becomes unavailable. View uptime & performance graphs of your website monitors.
AppDynamics - Get real-time insight from your apps using Application Performance Management—how they’re being used, how they’re performing, where they need help.
Sensu - Monitor servers, services, application health, and business KPIs. Get notified about failures before your users do. Collect and analyze custom metrics. Give your business the competitive advantage it deserves.