Unless you 've been living in a cave for the last year, you know that server side (better: 'general purpose') JavaScript is all the rage. Everything started with CommonJS: the emerging standard spawned an ecosystem of compatible implementations competing against each other while advancing the JavaScript state of the art.

Then, NodeJS happened: An async only JavaScript platform, powered by V8, not really interested in CommonJS conformance. RY (the new DHH) managed to grab the attention of the developer community with cool marketing, leaving other implementations in the shadows. One such great implementation that deserves more attention is RingoJS.

Some time ago I switched from Narwhal to Ringo and never looked back. I strongly believe that Ringo is the preeminent CommonJS implementation. Here is why:

• Ringo is quite possibly the most conformant CommonJS implementation, certainly more conformant than Narwhal and Node.
• Ringo is fast. If you tried Narwhal/Rhino and found start up times lacking or module reloading unacceptably slow check out Ringo! You will be pleasantly surprised. And while v8 may be faster than Rhino, the JVM is still quite optimized for server side environments. (And btw, in a modern Web application, time spent running the server side script is a negligible percentage of the total request/response cycle. You should probably work on optimizing network issues, database interactions, client side rendering, etc).
• Ringo is mature, stable and crash free. Ringo is the evolution of Helma, one of the first server side JavaScript platforms (more than 10 years in development). It's also based on the mature Java platform. Contrast this to reports of NodeJS crashes.
• Access to the gazillion of Java libraries. There is no merit in reinventing the wheel, just reuse code from the Java ecosystem. The integration between Java and JavaScript is seamless.
• Windows compatibility. OK, Windows sucks, but still, a lot of engineers use Windows as a development platform. Ringo apps work on Windows out of the box.
• Support for synchronous and asynchronous APIs. Use what's best for your application.
• Thanks to AppengineJS you can run your Ringo applications on Google's scalable infrastructure.
• The lead developer is extremely talented and friendly.
• Stop drinking the Kool-Aid! Engineer your application on top of a mature, conformant and compatible platform: RingoJS.

Update: Removed a controversial link.