Heroku - Agile deployment platform for Ruby, Node.js, Clojure, Java, Python, and Scala. Setup takes only minutes and deploys are instant through git. Leave tedious server maintenance to Heroku and focus on your code.

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.

Pivotal - Pivotal Software provides enterprise PaaS-based solutions.

Platypus - Realtime server monitoring and reporting

Google App Engine - A powerful platform to build web and mobile apps that scale automatically.

Nagios - Complete monitoring and alerting for servers, switches, applications, and services