Empire vs Google App Engine: What are the differences?

Developers describe Empire as "A Self-Hosted PaaS Built on Docker and Amazon ECS". Empire is a control layer on top of Amazon EC2 Container Service (ECS) that provides a Heroku like workflow. It conforms to a subset of the Heroku Platform API, which means you can use the same tools and processes that you use with Heroku, but with all the power of EC2 and Docker. On the other hand, Google App Engine is detailed as "Build web applications on the same scalable systems that power Google applications". Google has a reputation for highly reliable, high performance infrastructure. With App Engine you can take advantage of the 10 years of knowledge Google has in running massively scalable, performance driven systems. App Engine applications are easy to build, easy to maintain, and easy to scale as your traffic and data storage needs grow.

Empire and Google App Engine can be categorized as "Platform as a Service" tools.

Empire is an open source tool with 2.53K GitHub stars and 156 GitHub forks. Here's a link to Empire's open source repository on GitHub.