That’s really a good question @karthik. Even I had those doubts when I was introduced into ML and IR. So, to make the explanations simple and understanding for beginners too, I am not going too much into the technical aspects of it.
So Keras is built on Theano or Tensorflow. i.e, it uses them as the backend and makes higher level functions easy to construct. Keras is a ‘programming’ framework, where you actually program the model with parameters and redefine them with newer layers too. Whereas, Kur is a ‘configuration’ framework, where it take a config.yaml file to do everything. In KUR you won’t code rather you define a model in yaml file.
If you have anything more specific to ask, please feel free.