SpecialJson

SpecialJson is a JSON-like data interchange format designed to embed explicit type information and rich metadata within a JSON-compatible structure. It seeks to preserve JSON’s readability and widespread tool support while adding optional typing, references, and descriptive annotations that can aid validation, serialization, and application logic.

In SpecialJson, data remains expressed as standard JSON values, but developers may employ wrappers or profile fields to convey non-native types. A common convention is to represent typed values as objects such as { "$type": "date", "$value": "2025-12-25" }. Optional top-level fields like "$special" and "$schema" can declare the document version and the profile in use. This design maintains interoperability with existing JSON parsers while enabling specialized tooling to interpret the extended semantics.

Key features include explicit type annotations, support for advanced scalar types (date, time, decimal, binary), nullable and optional fields, and metadata blocks. SpecialJson also offers lightweight mechanisms for referencing other objects via identifiers (for example, { "$id": "user1" } and { "$ref": "user1" }), which can describe graphs or linked data without duplicating payloads.

Validation and tooling are centered on a schema concept, analogous to JSON Schema, that defines permitted types and structures. Converters and validators can translate between SpecialJson and standard JSON, or between SpecialJson and domain-specific models, enabling gradual adoption.

Example: {"$special":"profile-v1","$schema":"https://example.org/specialjson/schema.json","data":{"name":"Alice","birthDate":{"$type":"date","$value":"1990-01-01"}}}.

See also: JSON, JSON Schema, JSON-LD.