This research aims to examine the relationship between banking apps and their influence on customer trust and retention. Given the increasing reliance on digital platforms, the study understands how mobile apps influence customer behavior for the long-term growth of these institutions. Data was gathered from a sample of 400 clients through a survey and analyzed using SPSS 26 and structural equation modeling (SEM) with AMOS 25 to draw conclusive suggestions. The findings indicate that several important qualities of a website, including customer interaction, aesthetics, ease of use, personalization, and trust, favorably impact customer retention. The study will provide insight into the specific challenges faced by Islamic banks in aligning mobile app features while maintaining usability and security standards. It represents the initial attempt to investigate the impact of fundamental website characteristics on customer engagement. It is a completely novel insight for bank marketers, using empirical evidence to foster loyalty in Bangladesh.