This presentation will showcase a groundbreaking approach to digital mental health through the co-design, development, and evaluation of single-session interventions (SSIs) for early intervention in eating disorders (EDs) among university students. Using the NourishED Mind app, initially developed for a general youth population, we will refine nine SSIs specifically for university students. This research employs a co-design methodology, integrating student feedback to ensure interventions are user-centered, engaging, and clinically effective. SSIs are structured, targeted programs designed to create meaningful change in a single session, delivered through clinics, providers, or digital platforms (Schleider et al., 2020). Although research on SSIs for EDs is still emerging, early findings show promising outcomes, making this a groundbreaking approach to ED prevention (Yeager & Dweck, 2020; Zhou et al., 2020). The intervention content combines psychoeducation, interactive activities, and evidence-based therapeutic approaches that are transdiagnostic i.e., address disordered eating, anxiety, and depression. The co-design process unfolds over four phases: Phase 1: Identifying the top 9 psychological processes for intervention, guided by student feedback and Wade et al.’s (2025) framework. Phase 2: Conducting focus groups to refine SSIs, aligning student preferences with Delphi study findings. Phase 3: Adapting content to ensure cultural relevance and user appropriateness. Phase 4: Testing the refined SSIs, gathering critical feedback on engagement, user experience, and effectiveness. Then, a final expert review ensures the interventions uphold their theoretical and empirical integrity. Despite the growing demand for digital mental health interventions, challenges like attrition and adherence hinder effectiveness. Research shows that personalization, guided support, and interactive features improve engagement and outcomes (Nicolaou et al., 2022; Karekla et al., 2022). By leveraging co-design, this project directly addresses these barriers, ensuring SSIs are clinically robust and user-friendly. A core framework shaping intervention development is the B.E.S.T. model, which enhances engagement and learning: B: Brain science to normalize key concepts E: Empowering students to take on a “helper” or “expert” role S: Saying-is-believing exercises to reinforce learning T: Testimonials and evidence from valued others These structured interventions offer a low-cost, scalable solution for early ED prevention, making them ideal for digital delivery. They seamlessly integrate into students’ daily lives, reducing barriers such as stigma, cost, and accessibility. This presentation will provide a detailed breakdown of the methodology and findings from the co-design process, highlighting key insights from student feedback and expert validation. I will also outline next steps, including two upcoming randomized controlled trials (RCTs) to evaluate the long-term effectiveness and scalability of these interventions. Given the high prevalence of EDs among university students and barriers to traditional treatment, this research offers a practical, evidence-based solution with potential for real-world implementation. This research marks a critical first step in assessing engagement, adherence, and perceived impact, setting the foundation for large-scale application. By emphasizing scalability, personalization, and co-design, this work provides valuable insights into the future of digital mental health care. This presentation will offer actionable strategies for integrating evidence-based digital interventions into university and clinical settings, directly contributing to the advancement of scalable, accessible mental health solutions.