2019-09 Dialect

JSON Schema 2019-09 is a JSON media type for defining the structure of JSON data. JSON Schema asserts what a JSON document must look like, ways to extract information from it, and how to interact with it.

Specification	https://json-schema.org/draft/2019-09/draft-handrews-json-schema-02
Authors	Austin Wright Henry Andrews Ben Hutton Greg Dennis
Metaschema	https://json-schema.org/draft/2019-09/schema
Implementations	https://bowtie.report/#/dialects/draft2019-09
Release Notes	https://json-schema.org/draft/2019-09/release-notes

Using this dialect

To make use of this dialect, declare your schemas to have the dialect metaschema using the $schema keyword. For example:

{
  "$schema": "https://json-schema.org/draft/2019-09/schema" 
}

Citing this dialect

The recommended way to cite the JSON Schema 2019-09 dialect using BibTex is as follows:

@techreport{json-schema-2019-09,
  title = { JSON Schema: A Media Type for Describing JSON Documents },
  author = { Wright, Austin and Andrews, Henry and Hutton, Ben and Dennis, Greg },
  organization = { JSON Schema },
  year = { 2019 },
  url = { https://json-schema.org/draft/2019-09/draft-handrews-json-schema-02 }
}

Vocabularies

A curated set of vocabularies defined for this JSON Schema dialect.

Core Official Included By Default

A mandatory vocabulary that defines keywords that are either required in order to process any schema or meta-schema, including those split across multiple documents, or exist to reserve keywords for purposes that require guaranteed interoperability. Read more about this vocabulary.

Keyword	Kind	Instance	Summary
$schema	Identifier	Any	This keyword is both used as a JSON Schema dialect identifier and as a reference to a JSON Schema which describes the set of valid schemas written for this particular dialect.
$id	Identifier	Any	This keyword declares an identifier for the schema resource.
$ref	Applicator	Any	This keyword is used to reference a statically identified schema.
$defs	Reserved Location	Any	This keyword reserves a location for schema authors to inline re-usable JSON Schemas into a more general schema.
$comment	Reserved Location	Any	This keyword reserves a location for comments from schema authors to readers or maintainers of the schema.
$recursiveAnchor	Identifier	Any	This keyword is used to dynamically identify a base URI at runtime by marking where such a calculation can start, and where it stops.
$recursiveRef	Applicator	Any	This keyword is used to reference an identified schema, deferring the full resolution until runtime, at which point it is resolved each time it is encountered while evaluating an instance.
$anchor	Identifier	Any	This keyword is used to create plain name fragments that are not tied to any particular structural location for referencing purposes, which are taken into consideration for static referencing.
$vocabulary	Identifier	Any	This keyword is used in meta-schemas to identify the required and optional vocabularies available for use in schemas described by that meta-schema.

Applicator Official Included By Default

A vocabulary that defines applicator keywords that are recommended for use as the basis of other vocabularies. Read more about this vocabulary.

Keyword	Kind	Instance	Summary
allOf	Applicator	Any	An instance validates successfully against this keyword if it validates successfully against all schemas defined by this keyword’s value.
anyOf	Applicator	Any	An instance validates successfully against this keyword if it validates successfully against at least one schema defined by this keyword’s value.
oneOf	Applicator	Any	An instance validates successfully against this keyword if it validates successfully against exactly one schema defined by this keyword’s value.
if	Applicator	Any	This keyword declares a condition based on the validation result of the given schema.
then	Applicator	Any	When `if` is present, and the instance successfully validates against its subschema, then validation succeeds against this keyword if the instance also successfully validates against this keyword’s subschema.
else	Applicator	Any	When `if` is present, and the instance fails to validate against its subschema, then validation succeeds against this keyword if the instance successfully validates against this keyword’s subschema.
not	Applicator	Any	An instance is valid against this keyword if it fails to validate successfully against the schema defined by this keyword.
properties	Applicator Annotation	Object	Validation succeeds if, for each name that appears in both the instance and as a name within this keyword’s value, the child instance for that name successfully validates against the corresponding schema.
patternProperties	Applicator Annotation	Object	Validation succeeds if, for each instance name that matches any regular expressions that appear as a property name in this keyword’s value, the child instance for that name successfully validates against each schema that corresponds to a matching regular expression.
additionalProperties	Applicator Annotation	Object	Validation succeeds if the schema validates against each value not matched by other object applicators in this vocabulary.
propertyNames	Applicator	Object	Validation succeeds if the schema validates against every property name in the instance.
dependentSchemas	Applicator	Object	This keyword specifies subschemas that are evaluated if the instance is an object and contains a certain property.
additionalItems	Applicator Annotation	Array	If `items` is set to an array of schemas, validation succeeds if each element of the instance not covered by it validates against this schema.
items	Applicator Annotation	Array	If set to a schema, validation succeeds if each element of the instance validates against it, otherwise validation succeeds if each element of the instance validates against the schema at the same position, if any
contains	Applicator	Array	Validation succeeds if the instance contains an element that validates against this schema.
unevaluatedItems	Applicator Annotation	Array	Validates array elements that did not successfully validate against other standard array applicators.
unevaluatedProperties	Applicator Annotation	Object	Validates object properties that did not successfully validate against other standard object applicators.

Validation Official Included By Default

A vocabulary that defines keywords that impose requirements for successful validation of an instance. Read more about this vocabulary.

Keyword	Kind	Instance	Summary
type	Assertion	Any	Validation succeeds if the type of the instance matches the type represented by the given type, or matches at least one of the given types.
enum	Assertion	Any	Validation succeeds if the instance is equal to one of the elements in this keyword’s array value.
const	Assertion	Any	Validation succeeds if the instance is equal to this keyword’s value.
minLength	Assertion	String	A string instance is valid against this keyword if its length is greater than, or equal to, the value of this keyword.
maxLength	Assertion	String	A string instance is valid against this keyword if its length is less than, or equal to, the value of this keyword.
pattern	Assertion	String	A string instance is considered valid if the regular expression matches the instance successfully.
maximum	Assertion	Number	Validation succeeds if the numeric instance is less than or equal to the given number.
exclusiveMinimum	Assertion	Number	Validation succeeds if the numeric instance is greater than the given number.
multipleOf	Assertion	Number	A numeric instance is valid only if division by this keyword’s value results in an integer.
exclusiveMaximum	Assertion	Number	Validation succeeds if the numeric instance is less than the given number.
minimum	Assertion	Number	Validation succeeds if the numeric instance is greater than or equal to the given number.
dependentRequired	Assertion	Object	Validation succeeds if, for each name that appears in both the instance and as a name within this keyword’s value, every item in the corresponding array is also the name of a property in the instance.
minProperties	Assertion	Object	An object instance is valid if its number of properties is greater than, or equal to, the value of this keyword.
maxProperties	Assertion	Object	An object instance is valid if its number of properties is less than, or equal to, the value of this keyword.
required	Assertion	Object	An object instance is valid against this keyword if every item in the array is the name of a property in the instance.
minItems	Assertion	Array	An array instance is valid if its size is greater than, or equal to, the value of this keyword.
maxItems	Assertion	Array	An array instance is valid if its size is less than, or equal to, the value of this keyword.
minContains	Assertion	Array	The number of times that the `contains` keyword (if set) successfully validates against the instance must be greater than or equal to the given integer.
maxContains	Assertion	Array	The number of times that the `contains` keyword (if set) successfully validates against the instance must be less than or equal to the given integer.
uniqueItems	Assertion	Array	If this keyword is set to the boolean value true, the instance validates successfully if all of its elements are unique.

Meta Data Official Included By Default

A vocabulary to defines general-purpose annotation keywords that provide commonly used information for documentation and user interface display purposes. Read more about this vocabulary.

Keyword	Kind	Instance	Summary
title	Annotation	Any	A preferably short description about the purpose of the instance described by the schema.
description	Annotation	Any	An explanation about the purpose of the instance described by the schema.
default	Annotation	Any	This keyword can be used to supply a default JSON value associated with a particular schema.
deprecated	Annotation	Any	This keyword indicates that applications should refrain from using the declared property.
examples	Annotation	Any	This keyword is used to provide sample JSON values associated with a particular schema, for the purpose of illustrating usage.
readOnly	Annotation	Any	This keyword indicates that the value of the instance is managed exclusively by the owning authority, and attempts by an application to modify the value of this property are expected to be ignored or rejected by that owning authority.
writeOnly	Annotation	Any	This keyword indicates that the value is never present when the instance is retrieved from the owning authority.

Format Official Included By Default

A vocabulary to defines semantic information about string-encoded values. Read more about this vocabulary.

Keyword	Kind	Instance	Summary
format	Annotation	String	Define semantic information about a string instance.

Content Official Included By Default

A vocabulary that defines keywords for annotating instances that contain non-JSON data encoded in JSON strings. Read more about this vocabulary.

Keyword	Kind	Instance	Summary
contentEncoding	Annotation	String	The string instance should be interpreted as encoded binary data and decoded using the encoding named by this property.
contentMediaType	Annotation	String	This keyword declares the media type of the string instance.
contentSchema	Annotation	String	This keyword declares a schema which describes the structure of the string.