Strategic DDD

Domain discovery and boundary definition at the organizational level. Strategic DDD answers: "Where are the boundaries?" and "How do contexts relate?"

Subdomain Classification

Subdomains exist in the problem space. Classify before modeling.

Type	Competitive advantage	Build or buy	DDD investment	Staffing
Core	Yes, unique differentiator	Build in-house	Full strategic + tactical	Senior talent
Supporting	No, enables core	Build (simplified) or outsource	Pragmatic tactical	Mid-level
Generic	No, commodity	Buy/integrate (Stripe, Auth0)	Minimal/none	Junior/integration

Decision heuristic: If two competitors solve this the same way, it's Generic. If your approach gives you an edge, it's Core. Everything else is Supporting.

Bounded Context Discovery

A bounded context is a software boundary within which a model is consistent. Different from subdomains (problem-space). They should align but are independent concepts.

Discovery Techniques

Language divergence (primary signal): When the same word means different things to different groups, you've found a boundary. "Account" in billing vs. "Account" in identity. "Product" in catalog vs. "Product" in inventory.

Organizational structure: Teams that communicate frequently often share a context. Teams with formal handoffs often have separate contexts. Conway's Law applies.

Consistency requirements: Where true invariants must be maintained transactionally defines aggregate boundaries, which cluster into contexts.

EventStorming Big Picture: Domain events placed on timeline. When events cluster into distinct swimlanes with different actors and vocabulary, those are context candidates.

Domain Storytelling: Actors perform activities on work objects. When actors, activities, or work objects change meaning, you've crossed a boundary.