JSONi

JSONi is a conceptual data-serialization format that extends the JSON data model with optional type annotations and metadata. Designed to preserve JSON's human-readability and broad interoperability, JSONi aims to enable stronger typing, schema awareness, and easier validation without requiring a complete rewrite of existing JSON workflows.

Core ideas include the addition of lightweight type hints and metadata blocks that can be used by validators and runtime engines to enforce constraints, while still allowing standard JSON parsers to consume the core data. JSONi documents are intended to be backwards compatible: any valid JSON document remains valid JSONi, and enhanced tooling can activate additional features when present.

In practice JSONi introduces optional fields or special prefixes to convey types, such as a top-level $schema and a per-value $type tag. For example, a person record might be represented as { "name": "Alice", "age": 30, "$type": "Person" }. This approach allows tooling to infer structure while preserving ordinary JSON data.

The term appears in academic discussions and hobbyist literature as a hypothetical extension to JSON; there is no widely adopted standard, and implementations are limited to experimental libraries and tutorials. Proponents argue it can reduce schema drift in dynamic systems, while opponents cite added complexity and potential confusion.

JSONi remains a niche concept with no formal standard or broad ecosystem. Its success depends on consensus around representation, semantics of types, and security concerns regarding metadata exposure in mixed environments.

Related topics include JSON, JSON Schema, JSON5, and data serialization formats.