tf2onnx is a converter utility that transforms deep learning models from TensorFlow (2.x), Keras, TensorFlow.js, and TFLite formats into the ONNX (Open Neural Network Exchange) standard. It operates via both command-line interface and Python API, enabling interoperability between different ML frameworks and deployment targets. The tool maps TensorFlow operations to ONNX opsets 14-18 and is part of the broader ONNX ecosystem maintained by the ONNX project.