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.
Salesforce Platform - Salesforce Platform is a comprehensive PaaS solution that paves the way for the developers to test, build, and mitigate the issues in the cloud application before the final deployment.
NodeChef - NodeChef provides managed hosting for Node.js and MongoDB apps.
AWS Lambda - Automatic, event-driven compute service
Render - Render is a unified platform to build and run all your apps and websites with free SSL, a global CDN, private networks and auto deploys from Git.