The Dutch Municipal Personal Records Database is an IT-innovation that enables the use of the civil registry by hundreds of (semi-)public organisations. Literature review and a case study show how this ‘basis registration’ creates a deep tension between system and lifeworld: citizens who do not fit the system’s criteria lose their access to the major part of public services. The instrumental rationality of the system simplifies the use of addresses for service delivery to one single definition, turns the consequences of address mutations into a black box, and reduces the discretionary space of street-level bureaucrats to handle with social complexities and unintended consequences of the system. This type of IT-innovations can, therefore, come to resemble a ‘digital cage’: a highly disciplining system that hinges on hardware and software design instead of Weberian rules and procedures.