Background: Mindfulness-based interventions (MBIs) have grown in popularity in recent years and have been shown to reduce stress and increase quality of life among older informal carers. A digital application delivering MBIs has been iteratively designed based on user-centered designed principles and aims to support older informal carers to manage stress and sleep. We describe a qualitative study with older informal carers and the resulting digital application. Methods: A qualitative study with 20 older adults took place over a 2-year period. Requirements gathering consisted of focus groups, interviews, and usability testing with older adults and informal carers. A high-fidelity mock-up of an application was designed and user-testing sessions held with five participants to gauge usability and effectiveness. Results: Focus group participants felt stress reduction is a significant issue which affects overall wellbeing, with a consensus that stress can have an adverse effect on sleep. An overarching theme throughout the informal carer interviews was carer burden and the sense of being overwhelmed. The sense of constant worry was a theme that also emerged, which could be addressed by the present moment focus of mindfulness (Helmes & Ward 2015 https://doi.org/10.1080/13607863.2015.1111862, Visser et al. 2015 https://doi.org/10.1007/s12671-014-0311-5). Usability testing sessions revealed previously overlooked user experience and interface issues, including icons and data visualizations. Analyses of these user interactions and qualitative feedback allowed for further iterations in the design cycle, meeting guidelines for best practice in a user-centred design approach. Conclusion: Insights from the requirements gathering and testing sessions provided an understanding of parameters of health important to older adults, feelings towards selfmonitoring, preferences for data visualizations, and attitudes to MBIs. The resulting application has been designed for older informal carers to manage stress through MBIs as well as monitor activity and sleep through tracking, data visualizations and educational advice.