Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
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.
Dokku - Docker powered mini-Heroku in around 100 lines of Bash
NodeChef - NodeChef provides managed hosting for Node.js and MongoDB apps.
Google Cloud Functions - A serverless platform for building event-based microservices.
Microsoft Azure - Windows Azure and SQL Azure enable you to build, host and scale applications in Microsoft datacenters.