  The Chopped RAndom Basis (CRAB) ansatz for quantum optimal control has been
proven to be a versatile tool to enable quantum technology applications,
quantum computing, quantum simulation, quantum sensing, and quantum
communication. Its capability to encompass experimental constraints -- while
maintaining an access to the usually trap-free control landscape -- and to
switch from open-loop to closed-loop optimization (including with remote access
-- or RedCRAB) is contributing to the development of quantum technology on many
different physical platforms. In this review article we present the
development, the theoretical basis and the toolbox for this optimization
algorithm, as well as an overview of the broad range of different theoretical
and experimental applications that exploit this powerful technique.
