django-services-selectors

Governs the service and selector layer: writing business logic, validation placement, transactions, and update helpers. Use when writing or changing a service or selector, a refund or similar multi-step write, row-level filtering or ownership checks, model validation, or deciding where a business rule belongs, including when asked to duplicate a rule in a serializer or view. Do not use for API classes that call them (django-apis-serializers) or for task retry and scheduling mechanics (django-celery).