According to the GitHub repository for the project, the listed features of the API are:
- Very Fast: It runs efficiently even on phones. 60 fps on my 2 year-old phone!
- Free and Open: It is completely open source and free of charge!
- Pure Standards: It works on any phone with webgl and webrtc
One reason this is an amazing accomplishment is that, historically, web-based 3D is not fast. While people have been trying 3D in web browsers since the mid-'90s with VRML, it is only in recent years that processors have sped up enough, and that the code has become optimized enough, to make web-based 3D experiences that were more than very basic objects.