PennyLane
PennyLane is the cross-platform Python framework for quantum computing, quantum machine learning, and quantum chemistry maintained by Xanadu. It provides automatic differentiation of hybrid quantum-classical computations across PyTorch, JAX, TensorFlow, and NumPy with a device-agnostic plugin model so the same circuit runs against simulators (Lightning, default.qubit) and hardware (IBM Q, IonQ, Rigetti, AWS Braket, Strawberry Fields). Apache-2.0, latest version 0.45.0 (May 2026), 3.2k+ stars.