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oneOf JSON Schema Keyword

Use oneOf when exactly one schema in a list must match.

Composition

Schema template

Try in Validator

JSON Schema

{
  "oneOf": [
    {
      "type": "string"
    },
    {
      "type": "boolean"
    }
  ]
}

Valid example JSON

true

Invalid example JSON

42

Fields

FieldTypeRequiredDescription
oneOfschema[]YesValidation passes only when exactly one schema matches. Ambiguous matches fail.

How to use this schema

Use oneOf for mutually exclusive payload variants. Add const discriminator fields when object branches could otherwise overlap.

Version support and combinations

This keyword or pattern is commonly supported across modern JSON Schema workflows. Check your validator for Draft-04, Draft-07, 2019-09, and 2020-12 behavior before relying on newer composition or conditional features.

Common combination: pair this reference with type, required, and properties so validation errors are specific enough for API clients and form users.

Batch validation seed

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Related reference pages

anyOf JSON Schema KeywordUse anyOf when a value may satisfy one or more schemas from a list.allOf JSON Schema KeywordUse allOf when a value must satisfy every schema in a list.const JSON Schema KeywordUse const when a value must match exactly one JSON value, such as a discriminator, version marker, or fixed feature flag.