In this article, we present the blue-c application programming interface (API) and discuss some of its performance characteristics. The blue-c API is a software toolkit for media-rich, collaborative, immersive virtual reality applications. It provides easy to use interfaces to all blue-c technology, including immersive projection, live 3D video acquisition and streaming, audio, tracking, and gesture recognition. We emphasize on our performance-optimized 3D video handling and rendering pipeline, which is capable of rendering 3D video inlays consisting of up to 30,000 fragments updated at 10 Hz in real time, enabling remote users to meet inside our virtual environment.