Guard your code with a domain layer
Numerous architectural models (Clean Architecture, Hexagonal, Onion, Domain‑Driven Design) present different terminology and slightly different structure, yet they converge on a single principle: Place business rules in their own layer. This inner layer is variously called entities, core, domain model, or business‑logic layer. I will refer to it as the domain layer. Without it, engineers must guess which mutations are legal and every feature starts with code‑base archaeology. A fictionalized crypto example The scenario below is distilled from common industry issues; the company, schema, and code are illustrative. ...