An increase in shipping quantities has put its strain on incumbent integration mechanisms in third-party outbound logistics. Therefore, Application Programming Interfaces (APIs) have recently witnessed increasing attention from practitioners in the logistics industry. However, implementing so-called Shipping APIs has proven to be difficult. With the goal of overcoming barriers to API adoption in outbound logistics, factors influencing logistics buyers’ adoption motivations are determined by adopting the case study methodology. It involved nine interviews with logistics buyers, fulfilment companies and integrators, after which findings were validated by means of a focus group with industry experts. Key challenges were found to be mainly technological; a lack of relative advantage when comparing it to the status quo and the risk of potential downtime were indicated by participants numerous times. Furthermore, among organizational factors, available resources were identified to play a moderate role and regarding environmental factors, the lack of marketing efforts surrounding Shipping APIs was argued to be of marginal impact. From this unique view of different stakeholders in the outbound logistics chain, this study hopes to promote API adoption and provide insights into the new emerging API paradigm within the supply chain network. The insights gained from this research can help to better formulate implementation strategies concerning integration technology, in an industry that is adapting to a new composition of consumer buying behaviour.