Maintain Your Brain (MYB)i is a randomised controlled trial (RCT) of multiple online interventions designed to target modifiable risk factors for Alzheimer's disease and dementia. Traditional clinical trial management systems (CTMS) requirements consist of features such as management of the study, site, subject (participant), clinical outcomes, external and internal requests, education, data extraction and reporting, security, and privacy. In addition to fulfilling these traditional requirements, MYB has a specific set of features that needs to be fulfilled. These specific requirements include: (i) support for multiple interventions within a study, (ii) flexible interoperability options with third-party software providers, (iii) study participants being able to engage in online activities via web-based interfaces throughout the trial (from screening to follow-up), (iv) ability to algorithmically personalize trial activities based on the needs of the participant, and (v) the ability to handle large volumes of data over a long period. This paper outlines how the existing CTMSs fall short in meeting these specific requirements. The presented system architecture, development approach and lessons learned in the implementation of the MYB digital platform will inform researchers attempting to implement CTMSs for trials comparable to MYB in the future.