PurposeThis study aims to explore the interactions between two different and potentially complementary boundary resources in coordinating solution networks in a digital platform context: boundary spanners (those individuals who span interorganizational boundaries) and boundary interfaces (the devices that help coordinate interfirm relationships, e.g. electronic data interchanges, algorithms or chatbots).Design/methodology/approachThe authors conducted a multiple case study of three firms using digital platforms to coordinate solution networks in the information communication technology and lighting facility industries. Data were collected from 30 semi-structured interviews, which are complemented by secondary data.FindingsAs task complexity increases, smarter digital interfaces are adopted. When the intelligence level of interfaces is low or moderate, they are only used as tools by boundary spanners or to support boundary spanners’ functions. When the intelligence level of interfaces is high or very high, boundary spanners design the interfaces and let them perform tasks autonomously. They are also sometimes employed to complement interfaces’ technological limitations and customers’ limited user ability.Research limitations/implicationsThe industry contexts of the cases may influence the results. Qualitative case data has limited generalizability.Practical implicationsThis study offers a practical tool for solution providers to effectively deploy boundary employees and digital technologies to offer diverse customized solutions simultaneously.OriginalityThis study contributes to the solution business literature by putting forward a framework of boundary resource interactions in coordinating solution networks in a digital platform context. It contributes to the boundary spanning literature by revealing the shifting functions of boundary spanners and boundary interfaces.