AppFog vs tsuru: What are the differences?

Developers describe AppFog as "Simple PaaS for Java, Python, Node, .Net, Ruby, PHP, MySQL, Mongo, and PostgreSQL". AppFog provides the infrastructure web developers need to build apps without worrying about IT tasks or having to wait days to get servers ready for writing code. AppFog’s web application technologies include PHP, NodeJS, Ruby, Python, Java, .NET, MySQL, and PostgreSQL. On the other hand, tsuru is detailed as "Extensible and open source Platform as a Service software". tsuru is an open source polyglot cloud application platform (PaaS). With tsuru, you don’t need to think about servers at all. You can write apps in the programming language of your choice, back it with add-on resources such as SQL and NoSQL databases, memcached, redis, and many others. You manage your app using the tsuru command-line tool and you deploy code using the Git revision control system, all running on the tsuru infrastructure.

AppFog and tsuru can be primarily classified as "Platform as a Service" tools.

Some of the features offered by AppFog are:

• Launches fast, runs fast- Varnish Cache and op-code caching run applications with less server load and accelerated performance.
• Reduces ops work- No more configuring servers, firewalls, Apache, security, or installing frameworks.
• Plays well with any SCM- Versioning is critical. AppFog is compatible with code management systems like git, svn, and mercurial.

On the other hand, tsuru provides the following key features:

• Fast and secure. The entire process is really simple with no special tools needed, just a simple git push.
• Scaling in Tsuru is completely painless. Just add a unit and Tsuru will take care of everything else.
• Tsuru is built to be extensible. Through services you can provide anything your application needs.

"The basic plan is free" is the top reason why over 3 developers like AppFog, while over 4 developers mention "Very receptive to contributions" as the leading cause for choosing tsuru.

tsuru is an open source tool with 3.14K GitHub stars and 421 GitHub forks. Here's a link to tsuru's open source repository on GitHub.