PT. Perkebunan Nusantara IV Regional III manages academic activity submissions, such as internships, educational visits, and research, through administrative processes that are still partially manual. This condition results in inefficiencies in data verification, documentation management, and information distribution. This study aims to design and develop a back-end system for academic activity submissions using a REST API architecture as part of an integrated Management Information System (MIS). The system is developed using the Laravel framework with the Agile Kanban methodology to visualize workflow, manage development tasks, and control Work-in-Progress (WIP). The REST API architecture enables modular, scalable, and platform-independent communication between the server and client applications. The system provides several key features, including digital submission of academic activities, real-time status validation, automated response letter generation via email, and management of internship activities such as attendance tracking and mentor task assignment. System evaluation is conducted using black-box testing to verify functional correctness, unit testing to validate individual modules of the API services, and performance testing to measure system responsiveness under concurrent requests. The results indicate that the developed system functions correctly according to the defined requirements and is capable of handling multiple requests with stable response times. Therefore, the proposed system contributes to improving efficiency, transparency, and accuracy in managing academic activity submissions at PT. Perkebunan Nusantara IV Regional III.