With the emergence of Dark Mode as a user interface design trend, it has increasingly been employed in operating systems, websites, and applications. There are several benefits to using Dark Mode: it can save battery life, reduce eye strain, is suitable for dark environments, and can be used as a reason for branding. This study aims to investigate whether Dark Mode applied to mobile commerce platforms impacts user trust and users’ perception of a brand in comparison to Light Mode. This study used a mixed-methods approach, including A/B testing followed by a questionnaire with Likert scale questions and open-ended questions, and involved 24 participants who were split into two groups, one testing a Light Mode version of a mobile commerce prototype and one testing a Dark Mode version. The results showed that while the Light Mode participant group had similar thoughts and feelings of the app which were mostly positive, the Dark Mode participant group was divided in their thoughts and feelings of the application related to trustworthiness and the perception of the brand. Dark Mode negatively impacts user trust and negatively impacts users’ perception of a brand. The findings of this study provide meaningful insights into the field of user interface design and branding and can serve as a reference for future studies within the field.