PyTorch

Open-source deep learning framework featuring dynamic computation graphs (eager mode) and a Python-first design. 87K+ GitHub stars. Transferred to the Linux Foundation (PyTorch Foundation) in September 2022.

PyTorch became the dominant framework for AI research and production, used by virtually every frontier lab. Its eager execution model, autograd system, and ecosystem (TorchVision, TorchAudio, TorchServe) made it the standard for model development. BSD License.