Theory
Once you've drawn your contexts, the relationships between them become first-class design decisions:
| Pattern | What it means |
|---|---|
| Partnership | Two contexts evolve together, mutual commitment. |
| Customer / Supplier | Upstream serves downstream; downstream has a voice. |
| Conformist | Downstream takes whatever upstream provides — no negotiation. |
| Anti-Corruption Layer (ACL) | Downstream wraps upstream behind its own model. |
| Shared Kernel | A small, jointly owned shared model. Expensive — use sparingly. |
| Open-Host Service / Published Language | Upstream publishes a stable protocol. |