The growth in e-commerce has led to increased demand for logistics services. This puts a pressure on third-party logistics (3PL) providers who struggle with increasing operating costs and heightened competition. These providers could potentially exploit the advantages of modularisation, but few studies address the design of modular logistics services. This study explores modular design of logistics services and proposes a model to describe logistics service architecture based on product architecture. A case study shows that warehousing services can be described in three domains.