Welby develops and operates PHR (Personal Health Record) platform services that enable patients with chronic diseases—including lifestyle-related diseases such as diabetes and hypertension, as well as cancer and other conditions—to self-manage their health and share medical information with healthcare providers via smartphone apps and web services. The company's primary revenue stream is its Disease Solution Service, where pharmaceutical companies commission the development of disease-specific PHR platforms to promote appropriate drug use and support patient treatment adherence, accounting for approximately 80% of total revenues. Welby also leverages accumulated patient-reported outcome (PRO) data for pharmaceutical marketing and clinical research purposes, with total cumulative app downloads reaching approximately 1.18 million as of December 2024.