With the widespread adoption of mobile payment technologies, their rapid and convenient nature has enhanced the ease of consumption but has also exacerbated the phenomenon of impulsive buying. Addressing the lack of digital intervention tools (DBCIs) to limit spending in the current market, this study explores how the design approaches of digital self-control tools (DSCTs) can be applied in payment scenarios, analyzing the effects of payment limits and interference designs on user experience and behavior. This study adopts the Design Science Research (DSR) methodology, developing a payment scenario prototype and conducting tests with 40 mobile payment users. The study examines design variables in the payment process, including limit display and payment interference designs (e.g., numerical input tasks or waiting tasks), to evaluate their effectiveness in mitigating impulsive buying behavior. The findings reveal that while interference designs can prolong users’ decision-making time, their actual effectiveness is limited. Participants generally emphasized the importance of providing clear prompts about the gap between spending amounts and predefined limits, as this effectively heightens financial awareness and promotes rational consumption. Based on these insights, future designs should prioritize optimizing limit display and prompt mechanisms, supplemented by moderate interference designs. This approach aims to balance the needs of users with varying levels of impulsive buying tendencies and ultimately achieve the goal of enhancing financial self-discipline through design.