The rapid growth of information technology has encouraged digital transformation in service-based businesses, including photography services. J_ART Photography currently uses an online booking application; however, its promotional activities are still conducted manually through individual WhatsApp messages, while payment confirmation relies on manual bank transfer verification. These processes reduce operational efficiency, increase administrative workload, and slow customer service. Therefore, this study aims to develop a Marketing Broadcast System and integrate the Midtrans Payment Gateway into the photography service booking application to improve promotional effectiveness, automate payment processing, and enhance service quality. This research employed the Research and Development (R&D) method using the Waterfall software development model, which consists of requirement analysis, system design, implementation, testing, and evaluation. Data were collected through observation, interviews, and literature review. System functionality was evaluated using the Black Box Testing method. The results indicate that the Marketing Broadcast System successfully automates promotional message delivery to customers, while the Midtrans Payment Gateway enables real-time payment processing and automatic transaction verification. Black Box Testing showed that all system features functioned according to the specified requirements. The developed system significantly improves operational efficiency, accelerates payment confirmation, reduces manual administrative tasks, and enhances customer service quality. In conclusion, integrating automated marketing and digital payment features into a single application provides an effective solution for optimizing business processes in photography service management and supports the digital transformation of small and medium-sized enterprises.