PreFlight - Preflight is an Automated Web Testing tool. Allows everyone to automate Web UI tests.
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.
AbTest.io - A free url shortener with A/B testing features
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.
Marpipe - Automate Your Ad Testing, Optimize Your Creative
Zabbix - Track, record, alert and visualize performance and availability of IT resources