project-root/
├── cmd/                # Main application entry points (binaries)
├── internal/           # Core domain logic (optional, restricts access to internal packages)
│   ├── domain/         # Domain layer (Entities, Value Objects, Aggregates, Interfaces)
│   ├── application/    # Application layer (Use cases, orchestrates domain logic)
│   ├── infrastructure/ # Infrastructure layer (Database, gRPC, HTTP, external APIs)
│   ├── interfaces/     # Interface adapters (Controllers, Repositories, Gateways)
│   └── config/         # Application configuration and settings
├── pkg/                # Shared libraries (reusable, domain-independent)
├── api/                # Protobuf/gRPC or OpenAPI definitions
└── docs/               # Documentation (e.g., architecture, API specs)