The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. products accessed via digital interfaces and devices to examine practices of interface design and the operation of digitally mediated power. Utilising interviews with HCSTC website designers and users of these products, the paper shows how these interfaces are designed and tested to manage frictions: practical, affective or emotional blocks that interrupt or stop users from applying for these products and entering into credit and debt. We suggest that the key role of interface design is to manage these frictions by guiding action in such a way to minimise intentional or propositional thought and negative affective states at key thresholds of the application process. The management of friction is enabled by practices of data driven design, where the contingency of human response is engineered through analytics in order to increase rates of application. Working through the example of HCSTC, the paper complicates a notion of control as a smooth or automatic operation of power, instead emphasising the necessity of both continuity and discontinuity as key to modulating action in a digital age. To understand the specificity of interface interactions and move beyond existing work on control, we offer a vocabulary of friction, thresholds, and transitions.