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.
NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.
Graylog - Graylog is an open source log management platform for collecting, indexing, and analyzing both structured and unstructured data.
Splunk - Splunk's operational intelligence platform helps unearth intelligent insights from machine data.
Prometheus - An open-source systems monitoring and alerting toolkit.
logstash - logstash is a tool for managing events and logs.