In our daily lives, we constantly participate in service processes, such as withdrawing money from an ATM or self-scanning in the supermarket. These examples illustrate value co-creation, where customers are involved in the creation of value through shared inventiveness and co-design. This doctoral research focuses on the conditions under which companies and their stakeholders benefit from a co-creation strategy. The first chapter discusses the characteristics of co-creation and its advantages and disadvantages as a strategy for customer engagement. Subsequently, a co-creation framework is presented, linking the success of co-creation to the characteristics of service interfaces. Three empirical studies investigate how companies can generate successful co-creation through service interfaces, the impact of customer engagement on employees, and the conditions for unique customer experiences. The final chapter summarizes the theoretical, methodological, and practical implications and offers suggestions for future research.