It's possible to create neural networks from raw code. But there are many code libraries you can use to speed up the process. These libraries include Microsoft CNTK, Google TensorFlow, Theano, PyTorch ...

For the sake of completeness, I’ve also included Keras in the figure below ... particularly in the world of Python. Developed by Google, TensorFlow might have been one of the first frameworks ...

On the compatibility and flexibility stage, TensorFlow 1.0 introduces a high level API including tf.layers, tf.metrics, and tf.losses. The Python APIs ... also included a Keras compatibility ...