CarerHelp is an online resource supporting Australian family carers providing palliative care to loved ones at home. To confidently care for a dying person, family carers require access to evidence-based resources, accessible day or night when healthcare professionals or services are unavailable. Given carer diversity, usability evaluations assist online developers in shaping information experiences to family carer's needs and abilities. This study aimed to use a comprehensive usability testing protocol to evaluate the prototype, with a sample involving six family carers aged 36-74 years. A concurrent think-aloud approach generated quantitative and qualitative feedback from scenario-based tasks. Single ease questions (SEQ) and computer satisfaction usability questionnaire (CSUQ) assessed end-user attitudes. Performance, SEQ, and CSUQ were calculated, errors were analyzed, and severity rating applied. Overall, family carers identified 54 errors. All carers detected highly severe errors impacting critical function
technical ability influenced error detection, affecting navigation, utility, and content. Language modification was guided by family carers' narratives, contextualizing interface use with real-life experiences. For the multidisciplinary development team, formal reporting of findings was advantageous in informing meaningful reiterative interface changes and giving a voice to family carers. This approach was essential to assist as many carers as possible in accessing palliative care information when needed.