This master’s thesis explores the potential of the service design approach in facilitating common communication, internal alignment, and collaboration among cross-functional teams within mature startups. The research focuses on a corporate travel startup that has been actively involved as both a collaboration partner and a client. To address the challenge of alignment within cross-functional teams at the onset of new projects, we have developed a solution called the ‘Project Roadmap Framework’. Throughout the study, various service design methods and tools are employed to facilitate the exploration and implementation of service design principles. Drawing upon existing literature in service design, startups, cross-functional team collaboration, communication, and organizational change, the research establishes a strong theoretical foundation and gains valuable insights into the factors influencing effective internal alignment and collaboration within a startup context. Following a mixed-method approach and leveraging the five stages of the design thinking framework, this study systematically addresses the research question and ensures the credibility and accuracy of the findings. The research employs diverse data collection methods, including workshops, interviews, prototyping, desk research, and surveys. The research results in the development of the Project Roadmap Framework, specifically tailored to meet the collaboration partner’s requirements and offer them a more holistic approach to their project management. This framework provides cross-functional teams with actionable steps, guidelines, and resources to establish a common communication ground and enhance collaboration at the beginning of projects. This thesis significantly contributes to both the theoretical understanding and practical application of service design in startup environments. It serves as an inspirational resource for individuals working in the field, offering insights and strategies to overcome common internal challenges faced in startup settings. By emphasizing the importance of service design, this research aims to foster improved collaboration and alignment within startups.