The world is rapidly urbanising, and urban informality is a central feature of our times. Conventional thinking views informality as corrosive to clean government, but new scholarship illuminates the complex relations between informality, power, and governance in cities. New technologies offer opportunities to disrupt entrenched power networks, tackle corruption, and ease the precarious lives of city dwellers. We look at how anti-corruption policies should be designed and implemented in urban settings marked by high levels of informality.