title: JSON Schema Media Types abbrev: docname: draft-ietf-httpapi-jsonschema-mediatypes-latest category: info
ipr: trust200902 area: Applications and Real-Time workgroup: HTTPAPI keyword: Internet-Draft
stand_alone: yes pi: [toc, tocindent, sortrefs, symrefs, strict, compact, comments, inline, docmapping]
venue: group: HTTPAPI type: Working Group home: https://datatracker.ietf.org/wg/httpapi/about/ mail: [email protected] arch: https://mailarchive.ietf.org/arch/browse/httpapi/ repo: rest-api github-issue-label: rest-api
ins: R. Polli
name: Roberto Polli
org: Digital Transformation Department, Italian Government
email: [email protected]
country: Italy
- ins: J. Desrosiers name: Jason Desrosiers org: Postman email: [email protected] country: USA
normative: YAML: title: YAML Ain't Markup Language Version 1.2 date: 2021-10-01 author: - ins: Oren Ben-Kiki - ins: Clark Evans - ins: Ingy dot Net target: https://yaml.org/spec/1.2/spec.html OAS: title: OpenAPI Specification 3.1.0 date: 2021-02-15 target: https://spec.openapis.org/oas/latest author: - ins: Darrel Miller - ins: Jeremy Whitlock - ins: Marsh Gardiner - ins: Mike Ralphson - ins: Ron Ratovsky - ins: Uri Sarid jsonschema: title: JSON Schema Core date: 2020-01-28 target: "https://json-schema.org/specification.html" author: - ins: A. Wright - ins: H. Andrews - ins: B. Hutton - ins: G. Dennis
informative:
--- abstract
This document registers the following media types used in APIs on the IANA Media Types registry: application/schema+json, and application/schema-instance+json,
--- middle
OpenAPI Specification [OAS] version 3 and above is a consolidated standard for describing HTTP APIs using the JSON {{!JSON=RFC8259}} and YAML [YAML] data format.
YAML media type registration is addressed in {{!YAML-MEDIATYPES=I-D.ietf-httpapi-yaml-mediatypes}}, which provides interoperability and security considerations.
OpenAPI media type registration is addressed in {{!OAS-MEDIATYPES=I-D.ietf-httpapi-rest-api-mediatypes}}, which provides interoperability and security considerations.
To increase interoperability when processing API specifications
and leverage content negotiation mechanisms when exchanging
OpenAPI Specification resources
this specification register the following media types:
application/schema+json,
and application/schema-instance+json,
{::boilerplate bcp14+}
This document uses the Augmented BNF defined in {{!RFC5234}} and updated by {{!RFC7405}}.
The terms "content", "content negotiation", "resource", and "user agent" in this document are to be interpreted as in {{!HTTP=RFC9110}}.
This section describes the information required to register the above media types according to {{!MEDIATYPE=RFC6838}}.
JSON Schema is a declarative domain-specific language for validating and annotating JSON documents (see {{jsonschema}}).
This document registers the media types associated with JSON Schema.
There are many dialects of JSON Schema in wide use today. The JSON Schema maintainers have released several dialects including draft-04, draft-07, and draft 2020-12. There are also several third-party JSON Schema dialects in wide use including the ones defined for use in [OAS] and MongoDB.
This specification defines little more than how to identify the dialect while leaving most of the semantics of the schema up to the dialect to define.
Clients MUST use the following order of precedence for determining the dialect of a schema:
- the
$schemakeyword ({{schema-keyword}}) - the "schema" media type parameter ({{schema-parameter}})
- the context of the enclosing document. This applies only when a schema is embedded within a document. The enclosing document could be another schema in the case of a bundled schema or it could be another type of document that includes schemas such as an OpenAPI document.
If none of the above result in identifying the dialect, client behavior is undefined.
The $schema keyword is used as a JSON Schema dialect identifier.
The value of this keyword MUST be a URI {{!RFC3986}}.
This URI SHOULD identify a meta-schema
that can be used to validate that the schema is syntactically correct according
to the dialect the URI identifies.
The dialect SHOULD define where the $schema keyword is allowed and/or
recognized in a schema,
but it is RECOMMENDED that dialects do not allow the schema to change within the same Schema Resource.
Media types MAY allow for a schema media type parameter, to support content
negotiation based on schema identifier (see {{Section 12 of HTTP}}).
The schema media type parameter MUST be a URI-reference {{!RFC3986}}.
The schema parameter identifies a schema that provides semantic information
about the resource the media type represents. When using the
application/schema+json media type, the schema parameter identifies the
dialect of the schema the media type represents.
The schema URI is opaque and SHOULD NOT automatically be dereferenced. Since
schema doesn't necessarily point to a network location, the "describedby"
relation is used for linking to a downloadable schema.
The following is an example of content negotiation where a user agent can accept two different versions of a "pet" resource. Each resource version is identified by a unique JSON Schema.
Request:
NOTE: '\' line wrapping per RFC 8792
GET /pet/1234 HTTP/1.1
Host: foo.example
Accept: \
application/schema-instance+json; schema="/schemas/v2/pet"; q=0.2, \
application/schema-instance+json; schema="/schemas/v1/pet"; q=0.1
Response:
NOTE: '\' line wrapping per RFC 8792
HTTP/1.1 200 Ok
Content-Type: \
application/schema-instance+json; schema="/schemas/v2/pet"
{
"petId": "1234",
"name": "Pluto",
...
}
In the following example, the user agent is able to accept two possible dialects of JSON Schema and the server replies with the latest one.
Request:
NOTE: '\' line wrapping per RFC 8792
GET /schemas/v2/pet HTTP/1.1
Host: foo.example
Accept: application/schema+json; \
schema="https://json-schema.org/draft/2020-12/schema", \
application/schema+json; \
schema="http://json-schema.org/draft-07/schema#"
Response:
NOTE: '\' line wrapping per RFC 8792
HTTP/1.1 200 OK
Content-Type: \
application/schema+json; \
schema="https://json-schema.org/draft/2020-12/schema"
{
"$id": "https://json-schema.org/draft/2020-12/schema",
"$schema": "https://json-schema.org/draft/2020-12/schema",
...
}
It is RECOMMENDED that instances described by a schema provide a link to a
downloadable JSON Schema using the link relation describedby, as defined by
Linked Data Protocol 1.0, section 8.1 {{!W3C.REC-ldp-20150226}}.
In HTTP, such links can be attached to any response using the Link header field
{{!LINK=RFC8288}}.
Link: <https://example.com/my-hyper-schema#>; rel="describedby"
Two fragment identifier structures are supported: JSON Pointers and plain-names.
The use of JSON Pointers as URI fragment identifiers is described in
{{!JSON-POINTER=RFC6901}}.
Fragment identifiers that are empty or start with a /, MUST be
interpreted as JSON Pointer fragment identifiers.
Plain-name fragment identifiers reference locally named locations in the document. The dialect determines how plain-name identifiers map to locations within the document. All fragment identifiers that do not match the JSON Pointer syntax MUST be interpreted as plain name fragment identifiers.
The media type for JSON Schema documents is application/schema+json.
This schema can be an official dialect or a third-party dialect.
The following information serves as the registration form for the application/schema+json media type.
Type name: : application
Subtype name: : schema+json
Required parameters: : N/A
Optional parameters:
- schema: A URI identifying the JSON Schema dialect the schema was written
for. If this value conflicts with the value of the
$schemakeyword in the schema, the$schemakeyword takes precedence.
Encoding considerations: : Same as "application/json"
Security considerations: : See the "Security Considerations" section of {{jsonschema}}
Interoperability considerations: : See the "General Considerations" section of {{jsonschema}}
Published specification: : this document
Applications that use this media type: : JSON Schema is used in a variety of applications including API servers and clients that validate JSON requests and responses, IDEs that valid configuration files, databases that store JSON.
Fragment identifier considerations: : See {{schema-fragment}}
Additional information:
-
Deprecated alias names for this type: N/A
-
Magic number(s): N/A
-
File extension(s): json, schema.json
-
Macintosh file type code(s): N/A
Person and email address to contact for further information: : See Authors' Addresses section.
Intended usage: : COMMON
Restrictions on usage: : N/A.
Author: : See Authors' Addresses section.
Change controller: : N/A
The application/schema-instance+json media type is an extension of the
{{JSON}} media type that just adds the schema media type parameter and
fragment identification.
The following information serves as the registration
form for the application/schema-instance+json media type.
Type name: : application
Subtype name: : schema-instance+json
Required parameters: : N/A
Optional parameters:
- schema: : A URI identifying a JSON Schema that provides semantic information about this JSON representation.
Encoding considerations: : Same as {{JSON}}
Security considerations: : Same as {{JSON}}
Interoperability considerations: : Same as {{JSON}}
Published specification: : this document
Applications that use this media type: : JSON Schema is used in a variety of applications including API servers and clients that validate JSON requests and responses, IDEs that valid configuration files, databases that store JSON, and more.
Fragment identifier considerations: : See {{schema-fragment}}
Additional information:
- Deprecated alias names for this type: N/A
- Magic number(s): N/A
- File extension(s): json
- Macintosh file type code(s): N/A
Person and email address to contact for further information: : See Authors' Addresses section.
Intended usage: : COMMON
Restrictions on usage: : N/A
Author: : See Authors' Addresses section.
Change controller: : N/A
Interoperability requirements for media type registrations are discussed in Section 4.6 of {{!MEDIATYPE=RFC6838}}.
Security requirements for media type registrations are discussed in Section 4.6 of {{!MEDIATYPE=RFC6838}}.
All JSON Schema Media Types might reference nested or external resources, as well as processable information like HTML.
Implementations that try to dereference or process those resource automatically might be subject to various security risks, from resource exhaustion (e.g., caused by cyclic references) to retrieval and processing of malicious code (e.g., embedded as markup language).
This specification defines the following new Internet media types {{MEDIATYPE}}.
IANA is asked to update the "Media Types" registry at https://www.iana.org/assignments/media-types with the registration information provided in the sections below.
|--------------------------------------|---------------------------------------------|
| Media Type | Registration Information Section |
|---|---|
| application/schema+json | {{schema-json}} of this document |
| application/schema-instance+json | {{schema-instance-json}} of this document |
| -------------------------------------- | --------------------------------------------- |
--- back
{: numbered="false"}
Thanks to Erik Wilde and David Biesack for being the initial contributors of this specification, and to Darrel Miller and Rich Salz for their support during the adoption phase.
In addition to the people above, this document owes a lot to the extensive discussion inside and outside the HTTPAPI workgroup. The following contributors have helped improve this specification by opening pull requests, reporting bugs, asking smart questions, drafting or reviewing text, and evaluating open issues:
Austin Wright, Ben Hutton and Jason Desrosiers.
{: numbered="false" removeinrfc="true"}
Q: Why this document? : After all these years, we still lack a proper media type for REST related document types. This has some security implications too (eg. wrt on identifying parsers or treat downloads)
{: numbered="false" removeinrfc="true"}
RFC EDITOR PLEASE DELETE THIS SECTION.
{:numbered="false" removeinrfc="true"}
- Split YAML registrations in a separate I-D.