Domains

Domains represent cross-cutting business and infrastructure concerns.

They define rules, data models, and invariants that apply across multiple systems.

Domains are authoritative.

Characteristics

A concern belongs in Domains if:

• it spans more than one system
• it owns business rules
• it has persistence or external dependencies
• multiple teams/features depend on it

Examples

• Billing
• Identity
• Notifications
• Analytics
• Permissions

Rule

Systems consume domains. Domains do not depend on systems.