The Network Exposure Function (NEF) is a key component of the 5G and Beyond 5G (B5G) network, providing standardized access for third-party applications to network data and capabilities. Among these capabilities is the Event Monitoring API, which allows external applications to subscribe to specific network events. One such event is the reporting of user equipment (UE) location changes, enabling services that rely on real-time location awareness. In this context, this paper presents the design and implementation of an open-source, cloudbased NEF Event Monitoring Application Programming Interface (API) that adheres to relevant 3rd Generation Partnership Project (3GPP) standards. The proposed architecture minimizes integration complexity and provides a flexible framework for efficient deployment and utilization of future 6G location services, fostering innovation in intelligent environments and enabling a wide range of third-party applications.