OBJECTIVES: The European RHAPSODY project sought to develop and test an online information and support programme for caregivers of individuals diagnosed with young onset dementia. The objectives were to assess user acceptability and satisfaction with the programme and to test outcome measures for a larger effectiveness study. DESIGN: A pilot randomised controlled trial in England, France, and Germany was conducted with 61 caregivers for adults with young onset Alzheimer's disease or frontotemporal degeneration.