During cargo handling between individual transport modes at seaport and hinterland terminals, high load fluctuations can often be observed during the course of the day. As a result, waiting times and congestion of trucks as well as suboptimal utilization of handling equipment can occur. In order to improve the flow, an increasing number of terminals are introducing so-called time window booking systems (ZFBS) to smooth out peak loads. However, practical experience has gradually shown that a rigid allocation of time slots does not lead to an overall optimum (optimum utilization of the terminal with minimum waiting times for the trucks). This is where the FLEXIKING project comes in. The goal is to demonstrate how a collaborative and flexible ZFBS can meet the interests of both the terminal and the trucking companies. A flexible time window booking system will be used to continuously optimize the number of handling windows at the transshipment point. At the same time, distributed artificial intelligence will enable collaborative adjustment of previously booked time slots.