Background <p>Mobile health (mHealth) interventions offer opportunities to improve access to safe, evidence-informed support for people affected by eating disorders (EDs). However, challenges remain around sustained engagement, inclusivity, and integration with care. The co-produced Eating Disorder Support App, developed by the Eating Disorder Health Integration Team (EDHIT) from Bristol Health Partners in the UK, aims to provide trusted, accessible information for individuals with lived experience, supporters, and healthcare professionals. This study examined user engagement, acceptability, and the perceived impact of the app on knowledge, confidence and support-seeking, while identifying opportunities for refinement.</p> Methods <p>A mixed-methods evaluation was conducted using an online survey and follow-up semi-structured interviews. Sixteen participants (people with lived experience, supporters, and healthcare professionals) completed a survey assessing app use, usability, satisfaction, and perceived impact; four took part in qualitative interviews exploring experiences in depth. Quantitative data were analysed descriptively, and qualitative data were analysed using conventional qualitative content analysis.</p> Results <p>Within this sample, participants reported high satisfaction with the app’s accessibility, clarity, and non-judgemental tone, with the majority (93.8%) rating its overall quality as good or excellent. Survey findings indicated perceived improvements in knowledge, confidence, and intentions to seek or support help-seeking. Qualitative content analysis produced four overarching categories, with ten subcategories, providing further insight into how the app functioned as a trusted, accessible adjunct to care, supporting understanding, reassurance, and emotional safety. Participants also highlighted areas for improvement, including the need for greater personalisation, expanded multimedia content, and clearer navigation to manage initial information load. Overall, findings highlighted the app’s perceived value, while identifying opportunities to enhance engagement and inclusivity.</p> Conclusions <p>This evaluation suggests that the Eating Disorder Support App may be an acceptable and useful digital resource that complements clinical care and supports self-management. Future evaluations should include larger and more diverse samples, longitudinal follow-up, and assessment of clinical outcomes to strengthen the understanding of impact. Continued co-production and lived-experience involvement are likely to enhance inclusivity, relevance, and sustained engagement in digital ED support tools.</p>