We provide insights that will inform the realisation of larger, more sophisticated quantum computers. The rapid increase in the power of today’s quantum computers has highlighted an issue critical to their use. Conventional approaches for detecting faults in a quantum computer are not keeping up with the demands of hardware. Opacity brings a fresh approach to take quantum computing beyond benchmarking. Our software, Quiver, maps out a detailed error landscape across a device, to pinpoint and suppress errors and verify operation across the full quantum stack.