Abstract
The GRAPEjl package (https://github.com/JuliaQuantumControl/GRAPE.jl) implements Gradient Ascent Pulse Engineering, a widely used method of quantum optimal control. Its purpose is to find controls that steer a quantum system in a particular way. This is a prerequisite for next-generation quantum technology, such as quantum computing or quantum sensing. GRAPEjl exploits the unique strengths of the Julia programming language to achieve both flexibility and numerical performance. It builds on the QuantumControljl framework.