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 | |
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 is used in meta-schemas to identify the required and optional vocabularies available for use in schemas described by that meta-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. |