PyTorch Lightning is an open-source Python library that provides a high-level interface for PyTorch. It serves as a lightweight high-performance framework that organizes PyTorch projects to decouple the research code from the engineering code, making deep learning experiments easier to read and reproduce. It is designed to create scalable deep learning models that can easily run on distributed hardware while keeping the models hardware agnostic.

In 2019, PyTorch Lightning was adopted by the NeurIPS Reproducibility Challenge as a standard for submitting PyTorch code.