In built environment design, involving immediate stakeholders is essential for an inclusive and democratic design decision-making process. Traditional public engagement methods, such as in-person meetings, focus groups, and town halls, often fail to democratize the design process, leading to unresponsive or undesirable outcomes. These methods face challenges in inclusivity, accessibility, and balancing time and scope, often resulting in mistrust and a lack of motivation among participants. These limitations emphasize the need for innovative tools that enable more inclusive and transparent community input. This paper presents D-DEM, an interactive web-based platform to democratize public engagement in built environment design. We also present the results of our mixed-method study with 20 participants evaluating D-DEM’s usability, utility, and adaptability across three hypothetical design proposals. Preliminary results show that D-DEM simplifies complex design data, fosters meaningful engagement, and empowers specialists and non-specialists to engage in data-informed discourse.