A build starts with a question about data
Most architecture conversations begin with a shape: services, storage, integration. The questions that actually decide the outcome come later, and they are all about data. Which system holds the record of truth, how fresh it is, and who is allowed to say so.
What the map is for
- Naming the system of record for each entity
- Recording how fresh each source is
- Marking the owner who can confirm it
The map is not documentation for its own sake. It is the artifact that stops two teams building the same integration twice, and it is usually the first thing a reviewer asks for and the hardest thing to produce.