Despite the enthusiasm for engaging in interorganizational collaboration to enable digital product innovation, firms often face challenges in integrating knowledge across organizational boundaries. Our research examines how collaborating firms use Interorganizational Systems (IOS) tools and project coordinators to overcome knowledge boundaries in different types of ideation tasks. Drawing on boundary-spanning theory, we conceptualize IOS tools as boundary objects, project coordinators as boundary spanners, and the interdependence of ideation tasks as moderators of the impacts of boundary objects and spanners on knowledge integration. Our findings suggest that IOS tools help overcome syntax and semantic knowledge boundaries by transferring and sharing information when the interdependence of idea implementation tasks is high, and project coordinators help overcome pragmatic knowledge boundaries by building reciprocity of innovation participants when the interdependence of idea generation tasks is high. Our research contributes to value co-creation literature by developing a boundary-spanning mechanism to explain the roles of boundary objects and boundary spanners in overcoming different knowledge boundaries to enable digital product innovation at the inter-firm level.