Domain Expert's Guide
Domain experts (DEs) are subject matter experts (SMEs) in some knowledge or problem domain. They are the authority on the language used to describe both problems and solutions within their domain or field of expertise. These individuals are recognized authorities, and they influence an organization’s product, service or strategic direction.
Domain experts may or may not be in leadership positions, but they are people who are broadly trusted for their knowledge of business rules, processes, technical details, and system requirements.
These are the EF_Huttons of the organization.
While not a comprehensive list, these people may be Architects, Analysts, Developers, Managers, QA Engineers, or even Call Center Agents, and line workers from the warehouse.
Domain Experts do not need to be well versed in DDD or Reactive Architecture initially. It is the job of the Author to act as a guide and mentor through these topics. But Domain Experts must be open to change what is for what could be. Reactive Architectures can be very challenging for people to digest. More specifically, quite often techniques used to implement distributed and reactive systems will change user experiences, expectations of consistency and availability, the means used to monitor and maintain systems and processes, and so on. Domain experts will need to come to understand the reasons for these changes and be able to evangelize them as they interact with their peers.