Google had google colab previously which also had GPU enabled infrastructure to use but somehow i found it too slow and too unstable to get concrete learning done.But Kaggle kernels in their current form should be probably used as learning environments as well as for development.
Learn deep learning with GPU enabled kaggle kernels and fastai MOOC
Shubrashankh Chatterjee

Google Colab has a limit of 12 continuous hours per sesssion. What are the limitations of GPU enabled Kaggle kernels?