Abstract Background Co-creation aims to democratize research and bridge the gap between research and practice. Key characteristics like empowerment and meaningful participation shape sustainable outcomes. However, existing frameworks like Arnstein’s Ladder of Citizen Participation broadly overlook individual method contributions. This study aims to address this gap by creating and validating a framework for intrinsic evaluation, guiding stakeholders and researchers in genuine co-creation of public health interventions. Methods We systematically screened and extracted frameworks aligned with five key co-creation characteristics to identify and evaluate methods. Through iterative testing, we identified key features for distinguishing methods and integrated them into a novel framework. Co-creation experts validated and refined this framework using the closed card sort method, qualitative assessment, and group discussions. Results The Co-Creation Rainbow framework includes key features from 20 existing frameworks, with an Individual-to-Collective Continuum, five sections (Informing, Understanding, Stimulating, Collaborating, and Collective Decision-making), and three overarching themes (Engage, Participate, and Empower). Analysis showed successful categorization of 436 methods and revealed a significant disparity in co-creation practices between researchers and practitioners. Conclusions The Co-Creation Rainbow framework provides a structured approach to evaluating and reporting co-creation processes. Acknowledging co-creation’s diversity, the framework aids in tailoring approaches for meaningful participation. By offering a unified language for diverse co-creation methods, the framework also facilitates transparent evaluation, enhancing the reliability and reproducibility of co-created public health interventions. Key messages • Employing a universal language across diverse co-creation methods is pivotal in fostering transparent evaluation, thereby bolstering the reliability of co-created public health interventions. • Effective collaboration of key stakeholders necessitates the use of suitable methods. By integrating diverse perspectives, public health interventions gain relevance, efficacy, and sustainability.