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.

Netflow Network Forensics - Netflow Network Forensics is an application monitoring tool that monitors packets and analyzes traffic activity for intrusion or malware detection.

eG Enterprise - From application performance to user experience to infrastructure usage, get performance answers from a single console. Troubleshoot fast with actionable insights.

SolarWinds Pingdom - With website monitoring from Pingdom, you will be the first to know when your website is down. No installation required. 14-day free trial.

Datadog APM - Datadog APM is one of the powerful tools that allows deep visibility into your application with out-of-the-box performance dashboards for web services, queues, and databases to observe requests, errors, or latency.

ScienceLogic - ScienceLogic simplifies data center, cloud, and network monitoring with its all-in-one platform.