The Deep Neural Nets (DNN) library is a deep learning framework designed to be small in size, computationally efficient and portable. We started the project as a fork of the popular OpenCV library, while removing some components that is not tightly related to the deep learning framework. Comparing to Caffe and many other implements, DNN is relatively independent to third-party libraries, (Yes, we don't require Boost and Database systems to be install before crafting your own network models) and it can be more easily portable to mobile systems, like iOS, Android and RaspberryPi etc. And more importantly, DNN is powerful! It supports both convolutional networks and recurrent networks, as well as combinations of the two.