Cassandra is a distributed, wide-column database built for write-heavy, multi-datacentre workloads. It prioritises availability and scalability over consistency. It requires upfront schema design aligned to access patterns. It was developed at Facebook for inbox search and released open-source in July 2008.
PyTorch is a Python-first deep learning library built by Meta in 2016 as Torch's successor. It enables rapid model prototyping via dynamic computation graphs (Autograd), tensor abstractions, and CUDA-accelerated training. As of 2025, it remains one of the most popular deep learning libraries—alongside TensorFlow and Keras—but its design prioritises researcher agility over production robustness, scalability, or deployment tooling.