Purpose The provision of Industry 4.0 solutions demands a vast range of technology domains. To provide these solutions, small and medium-sized enterprises (SMEs) may need the support of different supply chain actors through an inbound open innovation strategy. The authors study the contribution of four types of supply chain actors for inbound open innovation: suppliers, competitors with complementary technologies, R&D centers and customers. The authors analyze how these four actors moderate the effect of integrated Industry 4.0 solutions on three main competitive strategies: cost, focalization and differentiation. Design/methodology/approach The authors conducted a survey on 77 SMEs from the automation sector, using OLS regression with moderating effects. They considered the integration of 15 technologies and 7 classic automation activities in the provision of Industry 4.0 solutions. The authors also studied three competitive outputs – technology cost reduction (cost), customer loyalty (focalization) and technology innovation (differentiation) – as well as four supply chain actors (moderators). Findings Expanding the provision of Industry 4.0 technologies increases customer loyalty and technology innovation. Collaboration with competitors (complementary technologies) leverage these results and reduce technology costs. Integration between customers and R&D centers elevates costs but R&D centers can foster long-run innovation. Originality/value This study is the first to empirically investigate inbound open innovation in the supply chain for technology development in the context of Industry 4.0. The authors discuss how these actors contribute to four inbound open innovation activities: technology scouting; horizontal technology collaboration; vertical technology collaboration; and technology sourcing.