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JSON Schema

A vocabulary for annotating and validating JSON documents, defining structure, data types, and constraints.

Data ValidationAlso called: "json validation", "schema validation"

JSON Schema provides a contract for JSON data, enabling validation and documentation.

Core capabilities

  • Define required and optional fields.
  • Specify data types (string, number, boolean, array, object).
  • Set value constraints (min/max, patterns, enums).
  • Nest schemas for complex structures.
  • Reference and reuse schema definitions.

Example schema

{
  "type": "object",
  "properties": {
    "name": {"type": "string"},
    "age": {"type": "integer", "minimum": 0}
  },
  "required": ["name"]
}

Use cases

  • API request/response validation.
  • Configuration file validation.
  • Form generation and validation.
  • Documentation generation.
  • Code generation from schemas.

Benefits

  • Catch data errors early.
  • Self-documenting data structures.
  • Consistent validation across systems.
  • IDE autocomplete and hints.