Value Objects

When to use

• The user wraps a primitive (money, email, coordinate) in an immutable type with invariants.
• The user needs two domain values to be considered equal when their contents match, not their identity.
• The user passes bare strings or ints for domain concepts and wants a dedicated type to stop mix-ups.

When NOT to use

• Do not model something with a distinct identity and mutable lifecycle (a User, an Order) as a value object.
• Do not build a value object when the value is simply one of a small closed set of named options.

Core guidance