kindrecord

Kindrecord is a data modeling pattern used to represent a heterogeneous collection of entities within a single record by embedding a kind or type discriminator and a corresponding payload. The idea is to allow a single field to indicate what shape the rest of the data takes, enabling polymorphic records in serialized forms.

A kindrecord typically includes at least two parts: a kind field that names the variant, and a payload or fields that vary by kind. In strongly typed contexts this often maps to a discriminated union or sum type, while in loosely typed stores it functions as a dynamic schema indicator. Validation rules enforce that the payload matches the declared kind.

Common examples appear in API payloads that must support multiple resource kinds in a single endpoint, or log/event records where a single log line may encode different event types, such as user_created or item_purchased. Formats like JSON or protobuf are well-suited, because the kind field can be serialized alongside the type-specific data.

Benefits include schema evolution flexibility, forward and backward compatibility, and simplified transport of heterogeneous data. Drawbacks include potential data validation complexity, the risk of invalid kind values, and performance considerations for dynamic dispatch and unpacking.

Related concepts include discriminated unions, sum types, tagged unions, polymorphic records, and type fields in data schemas.