ONNX, or Open Neural Network Exchange, is an open-source format designed to facilitate the interoperability of machine learning models. It allows developers to create models in one framework and then transfer them to another for inference or further training, promoting flexibility and collaboration across different tools and platforms. By supporting various frameworks like PyTorch, TensorFlow, and scikit-learn, ONNX simplifies the deployment of machine learning models in diverse environments. This standardization helps streamline workflows, making it easier for data scientists and engineers to share and utilize models without being locked into a single ecosystem.