HTTP/1.1 200 OK
Content-Type: application/vnd.api+json; ext="https://jsonapi.org/ext/version"
// ...
  "type": "articles",
  "id": "1",
  "version:id": "42",
  "attributes": {
    "title": "Rails is Omakase"
// ...
 Rules for Profiles

The rules for profile usage are dictated by RFC
6906.
A profile MAY define document members and processing rules that are reserved
for implementors.
A profile MUST NOT define any query parameters except implementation-specific query parameters.
A profile MUST NOT alter or remove processing rules that have been defined
by this specification or by an extension. However, a profile
MAY define processing rules for query parameters whose processing rules
have been reserved for implementors to define at their discretion.
For example, a profile could define rules for interpreting the filter query
parameter, but it could not specify that relationship
names in the include query parameter are
space-separated instead of dot-separated.
Unlike extensions, profiles do not need to define a namespace for document
members because profiles cannot define specification semantics and thus cannot
conflict with current or future versions of this specification. However, it is
possible for profiles to conflict with other profiles. Therefore, it is the
responsibility of implementors to ensure that they do not support conflicting
profiles.
In the following example, a profile has defined a timestamps
attribute. According to the profile, the attribute must be an
object containing a created member and a modified member and these members’
values must use the RFC 3339 format.
With such a profile applied, a response might appear as follows:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json; profile="https://example.com/resource-timestamps"
// ...
  "type": "articles",
  "id": "1",
  "attributes": {
    "title": "Rails is Omakase",
    "timestamps": {
      "created": "2020-07-21T12:09:00Z",
      "modified": "2020-07-30T10:19:01Z"
// ...
 Content Negotiation

 Universal Responsibilities

Clients and servers MUST send all JSON:API payloads using the JSON:API media
type in the Content-Type header.
Clients and servers MUST specify the ext media type parameter in the
Content-Type header when they have applied one or more extensions to a
JSON:API document.
Clients and servers MUST specify the profile media type parameters in the
Content-Type header when they have applied one or more profiles to a JSON:API
document.
 Client Responsibilities

When processing a JSON:API response document, clients MUST ignore any
parameters other than ext and profile parameters in the server’s
Content-Type header.
A client MAY use the ext media type parameter in an Accept header to
require that a server apply all the specified extensions to the response
document.
A client MAY use the profile media type parameter in an Accept header
to request that the server apply one or more profiles to the response document.
  
Note: A client is allowed to send more than one acceptable media type in the
Accept header, including multiple instances of the JSON:API media type. This
allows clients to request different combinations of the ext and profile
media type parameters. A client can use quality values
to indicate that some combinations are less preferable than others. Media types
specified without a qvalue are equally preferable to each other, regardless of
their order, and are always considered more preferable than a media type with a
qvalue less than 1.




    

 Server Responsibilities

If a request specifies the Content-Type header with the JSON:API media type,
servers MUST respond with a 415 Unsupported Media Type status code if
that media type contains any media type parameters other than ext or
profile.
If a request specifies the Content-Type header with an instance of
the JSON:API media type modified by the ext media type parameter and that
parameter contains an unsupported extension URI, the server MUST respond
with a 415 Unsupported Media Type status code.
  
Note: JSON:API servers that do not support version 1.1 of this specification
  will respond with a 415 Unsupported Media Type client error if the ext or
  profile media type parameter is present.
If a request’s Accept header contains an instance of the JSON:API media type,
servers MUST ignore instances of that media type which are modified by a
media type parameter other than ext or profile. If all instances of that
media type are modified with a media type parameter other than ext or profile,
servers MUST respond with a 406 Not Acceptable status code. If every
instance of that media type is modified by the ext parameter and each contains
at least one unsupported extension URI, the server MUST also respond with a
406 Not Acceptable.
If the profile parameter is received, a server SHOULD attempt to apply any
requested profile(s) to its response. A server MUST ignore any profiles
that it does not recognize.
  
Note: The above rules guarantee strict agreement on extensions between the
  client and server, while the application of profiles is left to the discretion
  of the server.
Servers that support the ext or profile media type parameters SHOULD
specify the Vary header with Accept as one of its values. This applies to
responses with and without any profiles or extensions applied.
  
Note: Some HTTP intermediaries (e.g. CDNs) may ignore the Vary header
unless specifically configured to respect it.
 Document Structure

This section describes the structure of a JSON:API document, which is identified
by the JSON:API media type. JSON:API documents are
defined in JavaScript Object Notation (JSON) [RFC8259].
Although the same media type is used for both request and response documents,
certain aspects are only applicable to one or the other. These differences are
called out below.
Extensions MAY define new members within the document structure. These
members MUST comply with the naming requirements specified
below.
Unless otherwise noted, objects defined by this specification or any applied
extensions MUST NOT contain any additional members. Client and server
implementations MUST ignore non-compliant members.
  
Note: These conditions allow this specification to evolve through additive
changes.
 Top Level

A JSON object MUST be at the root of every JSON:API request and response
document containing data. This object defines a document’s “top level”.
A document MUST contain at least one of the following top-level members:
  
data: the document’s “primary data”.
  
errors: an array of error objects.
  
meta: a meta object that contains non-standard
meta-information.
  
a member defined by an applied extension.
The members data and errors MUST NOT coexist in the same document.
A document MAY contain any of these top-level members:
  
jsonapi: an object describing the server’s implementation.
  
links: a links object related to the primary data.
  
included: an array of resource objects that are related to the primary
data and/or each other (“included resources”).
If a document does not contain a top-level data key, the included member
MUST NOT be present either.
The top-level links object MAY contain the following members:
  
self: the link that generated the current response document. If a
document has extensions or profiles applied to it, this link SHOULD be
represented by a link object with the type target attribute specifying the
JSON:API media type with all applicable parameters.
  
related: a related resource link when the primary data represents a
resource relationship.
  
describedby: a link to a description document (e.g. OpenAPI or JSON
Schema) for the current document.
  
pagination links for the primary data.
  
Note: The self link in the top-level links object allows a client to
refresh the data represented by the current response document. The client
should be able to use the provided link without applying any additional
information. Therefore the link must contain the query parameters provided
by the client to generate the response document. This includes but is not
limited to query parameters used for [inclusion of related resources][fetching resources],
[sparse fieldsets][fetching sparse fieldsets], [sorting][fetching sorting],
[pagination][fetching pagination] and [filtering][fetching filtering].
The document’s “primary data” is a representation of the resource or collection
of resources targeted by a request.
Primary data MUST be either:
  
a single resource object, a single resource identifier object, or null,
for requests that target single resources
  
an array of resource objects, an array of
resource identifier objects, or
an empty array ([]), for requests that target resource collections
For example, the following primary data is a single resource object:
  "data": {
    "type": "articles",
    "id": "1",
    "attributes": {
      // ... this article's attributes
    "relationships": {
      // ... this article's relationships
The following primary data is a single resource identifier object that
references the same resource:
  "data": {
    "type": "articles",
    "id": "1"
A logical collection of resources MUST be represented as an array, even if
it only contains one item or is empty.
 Resource Objects

“Resource objects” appear in a JSON:API document to represent resources.
A resource object MUST contain at least the following top-level members:
Exception: The id member is not required when the resource object originates
at the client and represents a new resource to be created on the server. In that
case, a client MAY include a lid member to uniquely identify the resource
by type locally within the document.
In addition, a resource object MAY contain any of these top-level members:
  
attributes: an attributes object representing some of the resource’s data.
  
relationships: a relationships object describing relationships between
 the resource and other JSON:API resources.
  
links: a links object containing links related to the resource.
  
meta: a meta object containing non-standard meta-information about a
resource that can not be represented as an attribute or relationship.
Here’s how an article (i.e. a resource of type “articles”) might appear in a document:
// ...
  "type": "articles",
  "id": "1",
  "attributes": {
    "title": "Rails is Omakase"
  "relationships": {
    "author": {
      "links": {
        "self": "/articles/1/relationships/author",
        "related": "/articles/1/author"
      "data": { "type": "people", "id": "9" }
// ...
 Identification

As noted above, every resource object MUST contain a
type member. Every resource object MUST also contain an id member,
except when the resource object originates at the client and represents a new
resource to be created on the server. If id is omitted due to this exception,
a lid member MAY be included to uniquely identify the resource by type
locally within the document. The value of the lid member MUST be
identical for every representation of the resource in the document, including
resource identifier objects.
The values of the id, type, and lid members MUST be strings.
Within a given API, each resource object’s type and id pair MUST
identify a single, unique resource. (The set of URIs controlled by a server,
or multiple servers acting as one, constitute an API.)




    

The type member is used to describe resource objects that share common
attributes and relationships.
The values of type members MUST adhere to the same constraints as
member names.
  
Note: This spec is agnostic about inflection rules, so the value of type
can be either plural or singular. However, the same value should be used
consistently throughout an implementation.
 Fields

A resource object’s attributes and its relationships are collectively called
its “fields”.
Fields for a resource object MUST share a common namespace with each
other and with type and id. In other words, a resource can not have an
attribute and relationship with the same name, nor can it have an attribute
or relationship named type or id.
 Attributes

The value of the attributes key MUST be an object (an “attributes
object”). Members of the attributes object (“attributes”) represent information
about the resource object in which it’s defined.
Attributes may contain any valid JSON value, including complex data structures
involving JSON objects and arrays.
Keys that reference related resources (e.g. author_id) SHOULD NOT appear
as attributes. Instead, relationships SHOULD be used.
  
Note: See fields and member names for more restrictions on this container.
 Relationships

The value of the relationships key MUST be an object (a “relationships
object”). Each member of a relationships object represents
a “relationship” from the resource object
in which it has been defined to other resource objects.
Relationships may be to-one or to-many.
A relationship’s name is given by its key. The value at that key MUST be an
object (“relationship object”).
A “relationship object” MUST contain at least one of the following:

  
links: a links object containing at least one of the following:
      
self: a link for the relationship itself (a “relationship link”). This
link allows the client to directly manipulate the relationship. For example,
removing an author through an article’s relationship URL would disconnect
the person from the article without deleting the people resource itself.
When fetched successfully, this link returns the linkage
for the related resources as its primary data.
(See Fetching Relationships.)
      
related: a related resource link
      
a member defined by an applied extension.
  
data: resource linkage
  
meta: a meta object that contains non-standard meta-information about the
relationship.
  
a member defined by an applied extension.
A relationship object that represents a to-many relationship MAY also contain
pagination links under the links member, as described below. Any
pagination links in a relationship object MUST paginate the relationship
data, not the related resources.
  
Note: See fields and member names for more restrictions on this container.
 Related Resource Links

A “related resource link” provides access to resource objects linked
in a relationship. When fetched, the related resource object(s)
are returned as the response’s primary data.
For example, an article’s comments relationship could
specify a link that returns a collection of comment resource objects
when retrieved through a GET request.
If present, a related resource link MUST reference a valid URL, even if the
relationship isn’t currently associated with any target resources. Additionally,
a related resource link MUST NOT change because its relationship’s content
changes.
 Resource Linkage

Resource linkage in a compound document allows a client to link together all
of the included resource objects without having to GET any URLs via links.
Resource linkage MUST be represented as one of the following:
  
null for empty to-one relationships.
  
an empty array ([]) for empty to-many relationships.
  
a single resource identifier object for non-empty to-one relationships.
  
an array of resource identifier objects for non-empty to-many relationships.
  
Note: The spec does not impart meaning to order of resource identifier
objects in linkage arrays of to-many relationships, although implementations
may do that. Arrays of resource identifier objects may represent ordered
or unordered relationships, and both types can be mixed in one response
object.
For example, the following article is associated with an author:
// ...
  "type": "articles",
  "id": "1",
  "attributes": {
    "title": "Rails is Omakase"
  "relationships": {
    "author": {
      "links": {
        "self": "http://example.com/articles/1/relationships/author",
        "related": "http://example.com/articles/1/author"
      "data": { "type": "people", "id": "9" }
  "links": {
    "self": "http://example.com/articles/1"
// ...
The author relationship includes a link for the relationship itself (which
allows the client to change the related author directly), a related resource
link to fetch the resource objects, and linkage information.
 Resource Links

The optional links member within each resource object contains links
related to the resource.
If present, this links object MAY contain a self link that
identifies the resource represented by the resource object.
// ...
  "type": "articles",
  "id": "1",
  "attributes": {
    "title": "Rails is Omakase"
  "links": {
    "self": "http://example.com/articles/1"
// ...
A server MUST respond to a GET request to the specified URL with a
response that includes the resource as the primary data.
 Resource Identifier Objects

A “resource identifier object” is an object that identifies an individual
resource.
A “resource identifier object” MUST contain a type member. It MUST
also contain an id member, except when it represents a new resource to be
created on the server. In this case, a lid member MUST be included that
identifies the new resource.
The values of the id, type, and lid members MUST be strings.
A “resource identifier object” MAY also include a meta member, whose value is a meta object that
contains non-standard meta-information.
 Compound Documents

Servers MAY allow responses that include related resources along with the
requested primary resources. Such responses are called “compound documents”.
In a compound document, all included resources MUST be represented as an
array of resource objects in a top-level included member.
Every included resource object MUST be identified via a chain of
relationships originating in a document’s primary data. This means that
compound documents require “full linkage” and that no resource object can be
included without a direct or indirect relationship to the document’s primary
data.
The only exception to the full linkage requirement is when relationship fields
that would otherwise contain linkage data are excluded due to
sparse fieldsets requested by the client.
A complete example document with multiple included relationships:
  "data": [{
    "type": "articles",
    "id": "1",
    "attributes": {
      "title": "JSON:API paints my bikeshed!"
    "links": {
      "self": "http://example.com/articles/1"
    "relationships": {
      "author": {
        "links": {
          "self": "http://example.com/articles/1/relationships/author",
          "related": "http://example.com/articles/1/author"
        "data": { "type": "people", "id": "9" }
      "comments": {
        "links": {
          "self": "http://example.com/articles/1/relationships/comments",
          "related": "http://example.com/articles/1/comments"
        "data": [
          { "type": "comments", "id": "5" },
          { "type": "comments", "id": "12" }
  "included": [{
    "type": "people",
    "id": "9",
    "attributes": {
      "firstName": "Dan",
      "lastName": "Gebhardt",
      "twitter": "dgeb"
    "links": {
      "self": "http://example.com/people/9"
  }, {
    "type": "comments",
    "id": "5",
    "attributes": {
      "body": "First!"
    "relationships": {
      "author": {
        "data": { "type": "people", "id": "2" }
    "links": {
      "self": "http://example.com/comments/5"
  }, {
    "type": "comments",
    "id": "12",
    "attributes": {
      "body": "I like XML better"
    "relationships": {
      "author": {
        "data": { "type": "people", "id": "9" }
    "links": {
      "self": "http://example.com/comments/12"
A compound document MUST NOT include more than one resource object for
each type and id pair.




    

  
Note: In a single document, you can think of the type and id as a
composite key that uniquely references resource objects in another part of
the document.
  
Note: For resources that do not contain an id member but do contain a lid,
the lid is sufficient to establish resource identity and thus linkage between
resource objects and resource identifier objects throughout the document.
  
Note: This approach ensures that a single canonical resource object is
returned with each response, even when the same resource is referenced
multiple times.
 Meta Information

Where specified, a meta member can be used to include non-standard
meta-information. The value of each meta member MUST be an object (a
“meta object”).
Any members MAY be specified within meta objects.
For example:
  "meta": {
    "authors": [
      "Yehuda Katz",
      "Steve Klabnik",
      "Dan Gebhardt",
      "Tyler Kellen"
  "data": {
    // ...
 Links

Where specified, a links member can be used to represent links. The value
of this member MUST be an object (a “links object”).
Within this object, a link MUST be represented as either:

  
a string whose value is a URI-reference [RFC3986 Section 4.1]
pointing to the link’s target,
  
a link object or
  
null if the link does not exist.
A link’s relation type SHOULD be inferred from the name of the link unless the
link is a link object and the link object has a rel member.
A link’s context is the top-level object, resource
object, or relationship object in which it
appears.
In the example below, the self link is a string whereas the related link is
a link object. The related link object provides additional information
about the targeted related resource collection as well as a schema that serves
as a description document for that collection:
"links": {
  "self": "http://example.com/articles/1/relationships/comments",
  "related": {
    "href": "http://example.com/articles/1/comments",
    "title": "Comments",
    "describedby": "http://example.com/schemas/article-comments",
    "meta": {
      "count": 10
 Link objects

A “link object” is an object that represents a web link.
A link object MUST contain the following member:
  
href: a string whose value is a URI-reference [RFC3986 Section 4.1]
pointing to the link’s target.
A link object MAY also contain any of the following members:
  
rel: a string indicating the link’s relation type. The string MUST be a
valid link relation type.
  
describedby: a link to a description document (e.g. OpenAPI or JSON
Schema) for the link target.
  
title: a string which serves as a label for the destination of a link
such that it can be used as a human-readable identifier (e.g., a menu
entry).
  
type: a string indicating the media type of the link’s target.
  
hreflang: a string or an array of strings indicating the language(s) of the
link’s target. An array of strings indicates that the link’s target is
available in multiple languages. Each string MUST be a valid language tag
[RFC5646].
  
meta: a meta object containing non-standard meta-information about the
link.
  
Note: the type and hreflang members are only hints; the target resource
is not guaranteed to be available in the indicated media type or language
when the link is actually followed.
 JSON:API Object

A JSON:API document MAY include information about its implementation
under a top level jsonapi member. If present, the value of the jsonapi
member MUST be an object (a “jsonapi object”).
The jsonapi object MAY contain any of the following members:
  
version - whose value is a string indicating the highest JSON:API version
supported.
  
ext - an array of URIs for all applied extensions.
  
profile - an array of URIs for all applied profiles.
  
meta - a meta object that contains non-standard meta-information.
Clients and servers MUST NOT use an ext or profile member for content
negotiation. Content negotiation MUST only happen based on media type
parameters in Content-Type header.
A simple example appears below:
  "jsonapi": {
    "version": "1.1",
    "ext": [
      "https://jsonapi.org/ext/atomic"
    "profile": [
      "http://example.com/profiles/flexible-pagination",
      "http://example.com/profiles/resource-versioning"
If the version member is not present, clients should assume the server
implements at least version 1.0 of the specification.
  
Note: Because JSON:API is committed to making additive changes only, the
version string primarily indicates which new features a server may support.
 Member Names

Implementation and profile defined member names used in a JSON:API document
MUST be treated as case sensitive by clients and servers, and they MUST
meet all of the following conditions:




    

  
Member names MUST contain at least one character.
  
Member names MUST contain only the allowed characters listed below.
  
Member names MUST start and end with a “globally allowed character”,
as defined below.
To enable an easy mapping of member names to URLs, it is RECOMMENDED that
member names use only non-reserved, URL safe characters specified in RFC 3986.
 Allowed Characters

The following “globally allowed characters” MAY be used anywhere in a member name:
  
U+0061 to U+007A, “a-z”
  
U+0041 to U+005A, “A-Z”
  
U+0030 to U+0039, “0-9”
  
U+0080 and above (non-ASCII Unicode characters; not recommended, not URL safe)
Additionally, the following characters are allowed in member names, except as the
first or last character:
  
U+002D HYPHEN-MINUS, “-“
  
U+005F LOW LINE, “_”
  
U+0020 SPACE, “ “ (not recommended, not URL safe)
 Reserved Characters

The following characters MUST NOT be used in implementation and
profile defined member names:
  
U+002B PLUS SIGN, “+” (has overloaded meaning in URL query strings)
  
U+002C COMMA, “,” (used as a separator between relationship paths)
  
U+002E PERIOD, “.” (used as a separator within relationship paths)
  
U+005B LEFT SQUARE BRACKET, “[” (used in query parameter families)
  
U+005D RIGHT SQUARE BRACKET, “]” (used in query parameter families)
  
U+0021 EXCLAMATION MARK, “!”
  
U+0022 QUOTATION MARK, ‘”’
  
U+0023 NUMBER SIGN, “#”
  
U+0024 DOLLAR SIGN, “$”
  
U+0025 PERCENT SIGN, “%”
  
U+0026 AMPERSAND, “&”
  
U+0027 APOSTROPHE, “’”
  
U+0028 LEFT PARENTHESIS, “(“
  
U+0029 RIGHT PARENTHESIS, “)”
  
U+002A ASTERISK, “*”
  
U+002F SOLIDUS, “/”
  
U+003A COLON, “:”
  
U+003B SEMICOLON, “;”
  
U+003C LESS-THAN SIGN, “<”
  
U+003D EQUALS SIGN, “=”
  
U+003E GREATER-THAN SIGN, “>”
  
U+003F QUESTION MARK, “?”
  
U+0040 COMMERCIAL AT, “@” (except as first character in @-Members)
  
U+005C REVERSE SOLIDUS, “\”
  
U+005E CIRCUMFLEX ACCENT, “^”
  
U+0060 GRAVE ACCENT, “`”
  
U+007B LEFT CURLY BRACKET, “{“
  
U+007C VERTICAL LINE, “|”
  
U+007D RIGHT CURLY BRACKET, “}”
  
U+007E TILDE, “~”
  
U+007F DELETE
  
U+0000 to U+001F (C0 Controls)
 @-Members

Member names MAY also begin with an at sign (U+0040 COMMERCIAL AT, “@”).
Members named this way are called “@-Members”. @-Members MAY appear
anywhere in a document.
This specification provides no guidance on the meaning or usage of @-Members,
which are considered to be implementation semantics. @-Members
MUST be ignored when interpreting this specification’s definitions and
processing instructions given outside of this subsection. For example, an
attribute is defined above as any member of the attributes object.
However, because @-Members must be ignored when interpreting that definition, an
@-Member that occurs in an attributes object is not an attribute.
  
Note: Among other things, “@” members can be used to add JSON-LD data to a
JSON:API document. Such documents should be served with an extra header
to convey to JSON-LD clients that they contain JSON-LD data.
 Extension Members

The name of every new member introduced by an extension MUST be prefixed
with the extension’s namespace followed by a colon (:).
The remainder of the name MUST adhere to the rules for implementation
defined member names.
 Fetching Data

Data, including resources and relationships, can be fetched by sending a
GET request to an endpoint.
Responses can be further refined with the optional features described below.
 Fetching Resources

A server MUST support fetching resource data for every URL provided as:
  
a self link as part of the top-level links object
  
a self link as part of a resource-level links object
  
a related link as part of a relationship-level links object
For example, the following request fetches a collection of articles:
GET /articles HTTP/1.1
Accept: application/vnd.api+json
The following request fetches an article:
GET /articles/1 HTTP/1.1
Accept: application/vnd.api+json
And the following request fetches an article’s author:
GET /articles/1/author HTTP/1.1
Accept: application/vnd.api+json
 Responses

 200 OK

A server MUST respond to a successful request to fetch an individual
resource or resource collection with a 200 OK response.
A server MUST respond to a successful request to fetch a resource
collection with an array of resource objects or an empty array ([]) as
the response document’s primary data.
For example, a GET request to a collection of articles could return:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "http://example.com/articles"
  "data": [{
    "type": "articles",
    "id": "1",
    "attributes": {
      "title": "JSON:API paints my bikeshed!"
  }, {
    "type": "articles",
    "id": "2",
    "attributes": {
      "title": "Rails is Omakase"
A similar response representing an empty collection would be:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "http://example.com/articles"
  "data": []
A server MUST respond to a successful request to fetch an individual
resource with a resource object or null provided as
the response document’s primary data.

null is only an appropriate response when the requested URL is one that
might correspond to a single resource, but doesn’t currently.
  
Note: Consider, for example, a request to fetch a to-one related resource link.
This request would respond with null when the relationship is empty (such that
the link is corresponding to no resources) but with the single related resource’s
resource object otherwise.
For example, a GET request to an individual article could return:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "http://example.com/articles/1"
  "data": {
    "type": "articles",
    "id": "1",
    "attributes": {
      "title": "JSON:API paints my bikeshed!"
    "relationships": {
      "author": {
        "links": {
          "related": "http://example.com/articles/1/author"
If the above article’s author is missing, then a GET request to that related
resource would return:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "http://example.com/articles/1/author"
  "data": null
 404 Not Found

A server MUST respond with 404 Not Found when processing a request to
fetch a single resource that does not exist, except when the request warrants a
200 OK response with null as the primary data (as described above).
 Other Responses

A server MAY respond with other HTTP status codes.




    

A server MAY include error details with error responses.
A server MUST prepare responses, and a client MUST interpret
responses, in accordance with
HTTP semantics.
 Fetching Relationships

A server MUST support fetching relationship data for every relationship URL
provided as a self link as part of a relationship’s links object.
For example, the following request fetches data about an article’s comments:
GET /articles/1/relationships/comments HTTP/1.1
Accept: application/vnd.api+json
And the following request fetches data about an article’s author:
GET /articles/1/relationships/author HTTP/1.1
Accept: application/vnd.api+json
 Responses

 200 OK

A server MUST respond to a successful request to fetch a relationship
with a 200 OK response.
The primary data in the response document MUST match the appropriate
value for resource linkage, as described above for
relationship objects.
The top-level links object MAY contain self and related links,
as described above for relationship objects.
For example, a GET request to a URL from a to-one relationship link could
return:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "/articles/1/relationships/author",
    "related": "/articles/1/author"
  "data": {
    "type": "people",
    "id": "12"
If the above relationship is empty, then a GET request to the same URL would
return:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "/articles/1/relationships/author",
    "related": "/articles/1/author"
  "data": null
A GET request to a URL from a to-many relationship link could return:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "/articles/1/relationships/tags",
    "related": "/articles/1/tags"
  "data": [
    { "type": "tags", "id": "2" },
    { "type": "tags", "id": "3" }
If the above relationship is empty, then a GET request to the same URL would
return:
HTTP/1.1 200 OK
Content-Type: application/vnd.api+json
  "links": {
    "self": "/articles/1/relationships/tags",
    "related": "/articles/1/tags"
  "data": []
 404 Not Found

A server MUST return 404 Not Found when processing a request to fetch
a relationship link URL that does not exist.
  
Note: This can happen when the parent resource of the relationship
does not exist. For example, when /articles/1 does not exist, request to
/articles/1/relationships/tags returns 404 Not Found.
If a relationship link URL exists but the relationship is empty, then
200 OK MUST be returned, as described above.
 Other Responses

A server MAY respond with other HTTP status codes.
A server MAY include error details with error responses.
A server MUST prepare responses, and a client MUST interpret
responses, in accordance with
HTTP semantics.
 Inclusion of Related Resources

An endpoint MAY return resources related to the primary data by default.
An endpoint MAY also support an include query parameter to allow the
client to customize which related resources should be returned.
If an endpoint does not support the include parameter, it MUST respond
with 400 Bad Request to any requests that include it.
If an endpoint supports the include parameter and a client supplies it:
  
The server’s response MUST be a compound document with an included key — even if that included key holds an empty array (because the requested relationships are empty).
  
The server MUST NOT include unrequested resource objects in the included
section of the compound document.
The value of the include parameter MUST be a comma-separated (U+002C
COMMA, “,”) list of relationship paths. A relationship path is a dot-separated
(U+002E FULL-STOP, “.”) list of relationship names. An empty
value indicates that no related resources should be returned.
If a server is unable to identify a relationship path or does not support
inclusion of resources from a path, it MUST respond with 400 Bad Request.
  
Note: For example, a relationship path could be comments.author, where
comments is a relationship listed under a articles resource object, and
author is a relationship listed under a comments resource object.
For instance, comments could be requested with an article:
GET /articles/1?include=comments HTTP/1.1
Accept: application/vnd.api+json
In order to request resources related to other resources, a dot-separated path
for each relationship name can be specified:
GET /articles/1?include=comments.author HTTP/1.1
Accept: application/vnd.api+json
  
Note: Because compound documents require full linkage
(except when relationship linkage is excluded by sparse fieldsets), intermediate
resources in a multi-part path must be returned along with the leaf nodes. For
example, a response to a request for comments.author should include comments
as well as the author of each of those comments.
  
Note: A server may choose to expose a deeply nested relationship such as
comments.author as a direct relationship with an alternative name such as
commentAuthors. This would allow a client to request
/articles/1?include=commentAuthors instead of
/articles/1?include=comments.author. By exposing the nested relationship with
an alternative name, the server can still provide full linkage in compound
documents without including potentially unwanted intermediate resources.
Multiple related resources can be requested in a comma-separated list:
GET /articles/1?include=comments.author,ratings HTTP/1.1
Accept: application/vnd.api+json
Furthermore, related resources can be requested from a relationship endpoint:
GET /articles/1/relationships/comments?include=comments.author HTTP/1.1
Accept: application/vnd.api+json
In this case, the primary data would be a collection of
resource identifier objects that represent linkage to comments for an article,
while the full comments and comment authors would be returned as included data.
  
Note: This section applies to any endpoint that responds with primary
data, regardless of the request type. For instance, a server could support
the inclusion of related resources along with a POST request to create a
resource or relationship.
 Sparse Fieldsets

A client MAY request that an endpoint return only specific fields in the
response on a per-type basis by including a fields[TYPE] query parameter.
The value of any fields[TYPE] parameter MUST be a comma-separated (U+002C
COMMA, “,”) list that refers to the name(s) of the fields to be returned.
An empty value indicates that no fields should be returned.




    

If a client requests a restricted set of fields for a given resource type,
an endpoint MUST NOT include additional fields in resource objects of
that type in its response.
If a client does not specify the set of fields for a given resource type, the
server MAY send all fields, a subset of fields, or no fields for that
resource type.
GET /articles?include=author&fields[articles]=title,body&fields[people]=name HTTP/1.1
Accept: application/vnd.api+json
  
Note: The above example URI shows unencoded [ and ] characters simply for
readability. In practice, these characters should be percent-encoded. See
“Square Brackets in Parameter Names”.
  
Note: This section applies to any endpoint that responds with resources as
primary or included data, regardless of the request type. For instance, a
server could support sparse fieldsets along with a POST request to create
a resource.
 Sorting

A server MAY choose to support requests to sort resource collections
according to one or more criteria (“sort fields”).
  
Note: Although recommended, sort fields do not necessarily need to
correspond to resource attribute and relationship names.
  
Note: It is recommended that dot-separated (U+002E FULL-STOP, “.”) sort
fields be used to request sorting based upon relationship attributes. For
example, a sort field of author.name could be used to request that the
primary data be sorted based upon the name attribute of the author
relationship.
An endpoint MAY support requests to sort the primary data with a sort
query parameter. The value for sort MUST represent sort fields.
GET /people?sort=age HTTP/1.1
Accept: application/vnd.api+json
An endpoint MAY support multiple sort fields by allowing comma-separated
(U+002C COMMA, “,”) sort fields. Sort fields SHOULD be applied in the
order specified.
GET /people?sort=age,name HTTP/1.1
Accept: application/vnd.api+json
The sort order for each sort field MUST be ascending unless it is prefixed
with a minus (U+002D HYPHEN-MINUS, “-“), in which case it MUST be descending.
GET /articles?sort=-created,title HTTP/1.1
Accept: application/vnd.api+json
The above example should return the newest articles first. Any articles
created on the same date will then be sorted by their title in ascending
alphabetical order.
If the server does not support sorting as specified in the query parameter
sort, it MUST return 400 Bad Request.
If sorting is supported by the server and requested by the client via query
parameter sort, the server MUST return elements of the top-level
data array of the response ordered according to the criteria specified.
The server MAY apply default sorting rules to top-level data if
request parameter sort is not specified.
  
Note: This section applies to any endpoint that responds with a resource
collection as primary data, regardless of the request type.
 Pagination

A server MAY choose to limit the number of resources returned in a response
to a subset (“page”) of the whole set available.
A server MAY provide links to traverse a paginated data set (“pagination
links”).
Pagination links MUST appear in the links object that corresponds to a
collection. To paginate the primary data, supply pagination links in the
top-level links object. To paginate an included collection returned in
a compound document, supply pagination links in the corresponding links
object.
The following keys MUST be used for pagination links:
  
first: the first page of data
  
last: the last page of data
  
prev: the previous page of data
  
next: the next page of data
Keys MUST either be omitted or have a null value to indicate that a
particular link is unavailable.
Concepts of order, as expressed in the naming of pagination links, MUST
remain consistent with JSON:API’s sorting rules.
The page query parameter family is reserved for pagination. Servers and
clients SHOULD use these parameters for pagination operations.
  
Note: JSON API is agnostic about the pagination strategy used by a server, but
the page query parameter family can be used regardless of the strategy
employed. For example, a page-based strategy might use query parameters such
as page[number] and page[size], while a cursor-based strategy might use
page[cursor].
  
Note: This section applies to any endpoint that responds with a resource
collection as primary data, regardless of the request type.
 Filtering

The filter query parameter family is reserved for filtering data. Servers
and clients SHOULD use these parameters for filtering operations.
  
Note: JSON API is agnostic about the strategies supported by a server.
 Creating, Updating and Deleting Resources

A server MAY allow resources of a given type to be created. It MAY
also allow existing resources to be modified or deleted.
A request MUST completely succeed or fail (in a single “transaction”). No
partial updates are allowed.
  
Note: The type member is required in every resource object throughout requests and
responses in JSON:API. There are some cases, such as when POSTing to an
endpoint representing heterogeneous data, when the type could not be inferred
from the endpoint. However, picking and choosing when it is required would be
confusing; it would be hard to remember when it was required and when it was
not. Therefore, to improve consistency and minimize confusion, type is
always required.
 Creating Resources

A resource can be created by sending a POST request to a URL that represents
a collection of resources. The request MUST include a single resource object
as primary data. The resource object MUST contain at least a type member.
For instance, a new photo might be created with the following request:
POST /photos HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": {
    "type": "photos",
    "attributes": {
      "title": "Ember Hamster",
      "src": "http://example.com/images/productivity.png"
    "relationships": {
      "photographer": {
        "data": { "type": "people", "id": "9" }
If a relationship is provided in the relationships member of the
resource object, its value MUST be a relationship object with a data
member. The value of this key represents the linkage the new resource is to
have.
 Client-Generated IDs

A server MAY accept a client-generated ID along with a request to create
a resource. An ID MUST be specified with an id key, the value of
which MUST be a universally unique identifier. The client SHOULD use
a properly generated and formatted UUID as described in RFC 4122
[RFC4122].
  
NOTE: In some use-cases, such as importing data from another source, it
may be possible to use something other than a UUID that is still guaranteed
to be globally unique. Do not use anything other than a UUID unless you are
100% confident that the strategy you are using indeed generates globally
unique identifiers.
For example:
POST /photos HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": {
    "type": "photos",
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "attributes": {
      "title": "Ember Hamster",
      "src": "http://example.com/images/productivity.png"
A server MUST return 403 Forbidden in response to an unsupported request
to create a resource with a client-generated ID.
 Responses

 201 Created

If the requested resource has been created successfully and the server changes
the resource in any way (for example, by assigning an id), the server MUST
return a 201 Created response and a document that contains the resource as
primary data.
The response SHOULD include a Location header identifying the location
of the newly created resource, in order to comply with RFC
7231.
If the resource object returned by the response contains a self key in its
links member and a Location header is provided, the value of the self
member MUST match the value of the Location header.
HTTP/1.1 201 Created
Location: http://example.com/photos/550e8400-e29b-41d4-a716-446655440000
Content-Type: application/vnd.api+json
  "data": {
    "type": "photos",
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "attributes": {
      "title": "Ember Hamster",
      "src": "http://example.com/images/productivity.png"
    "links": {
      "self": "http://example.com/photos/550e8400-e29b-41d4-a716-446655440000"
A server MAY return a 201 Created response with a document that contains
no primary data if the requested resource has been created successfully and the
server does not change the resource in any way (for example, by assigning an
id or createdAt attribute). Other top-level members, such as meta, could
be included in the response document.




    

  
Note: Only servers that accept Client-Generated
IDs can avoid assigning an id to a new resource.
 202 Accepted

If a request to create a resource has been accepted for processing, but the
processing has not been completed by the time the server responds, the
server MUST return a 202 Accepted status code.
 204 No Content

If the requested resource has been created successfully and the server does not
change the resource in any way (for example, by assigning an id or createdAt
attribute), the server MUST return either a 201 Created status code and
response document (as described above) or a 204 No Content status code with no
response document.
 403 Forbidden

A server MAY return 403 Forbidden in response to an unsupported request
to create a resource.
 404 Not Found

A server MUST return 404 Not Found when processing a request that
references a related resource that does not exist.
 409 Conflict

A server MUST return 409 Conflict when processing a POST request to
create a resource with a client-generated ID that already exists.
A server MUST return 409 Conflict when processing a POST request in
which the resource object’s type is not among the type(s) that constitute the
collection represented by the endpoint.
A server SHOULD include error details and provide enough information to
recognize the source of the conflict.
 Other Responses

A server MAY respond with other HTTP status codes.
A server MAY include error details with error responses.
A server MUST prepare responses, and a client MUST interpret
responses, in accordance with
HTTP semantics.
 Updating Resources

A resource can be updated by sending a PATCH request to the URL that
represents the resource.
The URL for a resource can be obtained in the self link of the resource
object. Alternatively, when a GET request returns a single resource object as
primary data, the same request URL can be used for updates.
The PATCH request MUST include a single resource object as primary data.
The resource object MUST contain type and id members.
For example:
PATCH /articles/1 HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": {
    "type": "articles",
    "id": "1",
    "attributes": {
      "title": "To TDD or Not"
 Updating a Resource’s Attributes

Any or all of a resource’s attributes MAY be included in the resource
object included in a PATCH request.
If a request does not include all of the attributes for a resource, the server
MUST interpret the missing attributes as if they were included with their
current values. The server MUST NOT interpret missing attributes as null
values.
For example, the following PATCH request is interpreted as a request to
update only the title and text attributes of an article:
PATCH /articles/1 HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": {
    "type": "articles",
    "id": "1",
    "attributes": {
      "title": "To TDD or Not",
      "text": "TLDR; It's complicated... but check your test coverage regardless."
 Updating a Resource’s Relationships

Any or all of a resource’s relationships MAY be included in the resource
object included in a PATCH request.
If a request does not include all of the relationships for a resource, the server
MUST interpret the missing relationships as if they were included with their
current values. It MUST NOT interpret them as null or empty values.
If a relationship is provided in the relationships member of a resource
object in a PATCH request, its value MUST be a relationship object
with a data member. The relationship’s value will be replaced with the
value specified in this member.
For instance, the following PATCH request will update the author relationship of an article:
PATCH /articles/1 HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": {
    "type": "articles",
    "id": "1",
    "relationships": {
      "author": {
        "data": { "type": "people", "id": "1" }
Likewise, the following PATCH request performs a complete replacement of
the tags for an article:
PATCH /articles/1 HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": {
    "type": "articles",
    "id": "1",
    "relationships": {
      "tags": {
        "data": [
          { "type": "tags", "id": "2" },
          { "type": "tags", "id": "3" }
A server MAY reject an attempt to do a full replacement of a to-many
relationship. In such a case, the server MUST reject the entire update,
and return a 403 Forbidden response.
  
Note: Since full replacement may be a very dangerous operation, a server
may choose to disallow it. For example, a server may reject full replacement if
it has not provided the client with the full list of associated objects, and
does not want to allow deletion of records the client has not seen.
 Responses

 200 OK

If a server accepts an update but also changes the targeted resource in ways
other than those specified by the request (for example, updating the
updatedAt attribute or a computed sha), it MUST return a 200 OK
response and a document that contains the updated resource as primary data.




    

A server MAY return a 200 OK response with a document that contains no
primary data if an update is successful and the server does not change the
targeted resource in ways other than those specified by the request. Other
top-level members, such as meta, could be included in the response document.
 202 Accepted

If an update request has been accepted for processing, but the processing
has not been completed by the time the server responds, the server MUST
return a 202 Accepted status code.
 204 No Content

If an update is successful and the server doesn’t change the targeted
resource in ways other than those specified by the request, the server
MUST return either a 200 OK status code and response document (as
described above) or a 204 No Content status code with no response document.
 403 Forbidden

A server MUST return 403 Forbidden in response to an unsupported request
to update a resource or relationship.
 404 Not Found

A server MUST return 404 Not Found when processing a request to modify
a resource that does not exist.
A server MUST return 404 Not Found when processing a request that
references a related resource that does not exist.
 409 Conflict

A server MAY return 409 Conflict when processing a PATCH request to
update a resource if that update would violate other server-enforced
constraints (such as a uniqueness constraint on a property other than id).
A server MUST return 409 Conflict when processing a PATCH request in
which the resource object’s type or id do not match the server’s endpoint.
A server SHOULD include error details and provide enough information to
recognize the source of the conflict.
 Other Responses

A server MAY respond with other HTTP status codes.
A server MAY include error details with error responses.
A server MUST prepare responses, and a client MUST interpret
responses, in accordance with
HTTP semantics.
 Updating Relationships

Although relationships can be modified along with resources (as described
above), JSON:API also supports updating of relationships independently at
URLs from relationship links.
  
Note: Relationships are updated without exposing the underlying server
semantics, such as foreign keys. Furthermore, relationships can be updated
without necessarily affecting the related resources. For example, if an article
has many authors, it is possible to remove one of the authors from the article
without deleting the person itself. Similarly, if an article has many tags, it
is possible to add or remove tags. Under the hood on the server, the first
of these examples might be implemented with a foreign key, while the second
could be implemented with a join table, but the JSON:API protocol would be
the same in both cases.
  
Note: A server may choose to delete the underlying resource if a
relationship is deleted (as a garbage collection measure).
 Updating To-One Relationships

A to-one relationship can be updated by sending a PATCH request to a URL
from a to-one relationship link.
The PATCH request MUST include a top-level member named data containing
one of:
  
a resource identifier object corresponding to the new related resource.
  
null, to remove the relationship.
For example, the following request updates the author of an article:
PATCH /articles/1/relationships/author HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": { "type": "people", "id": "12" }
And the following request clears the author of the same article:
PATCH /articles/1/relationships/author HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": null
If the relationship is updated successfully then the server MUST return
a successful response.
 Updating To-Many Relationships

A to-many relationship can be updated by sending a PATCH, POST, or
DELETE request to a URL from a to-many relationship link.
For all request types, the body MUST contain a data member whose value
is an empty array or an array of resource identifier objects.
If a client makes a PATCH request to a URL from a to-many
relationship link, the server MUST either completely
replace every member of the relationship, return an appropriate error response
if some resources cannot be found or accessed, or return a 403 Forbidden
response if complete replacement is not allowed by the server.
For example, the following request replaces every tag for an article:
PATCH /articles/1/relationships/tags HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": [
    { "type": "tags", "id": "2" },
    { "type": "tags", "id": "3" }
And the following request clears every tag for an article:
PATCH /articles/1/relationships/tags HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": []
If a client makes a POST request to a URL from a
relationship link, the server MUST add the specified
members to the relationship unless they are already present. If a given type
and id is already in the relationship, the server MUST NOT add it again.
  
Note: This matches the semantics of databases that use foreign keys for
has-many relationships. Document-based storage should check the has-many
relationship before appending to avoid duplicates.
If all of the specified resources can be added to, or are already present
in, the relationship then the server MUST return a successful response.
  
Note: This approach ensures that a request is successful if the server’s
state matches the requested state, and helps avoid pointless race conditions
caused by multiple clients making the same changes to a relationship.
In the following example, the comment with ID 123 is added to the list of
comments for the article with ID 1:
POST /articles/1/relationships/comments HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": [
    { "type": "comments", "id": "123" }
If the client makes a DELETE request to a URL from a
relationship link the server MUST delete the specified
members from the relationship or return a 403 Forbidden response. If all of
the specified resources are able to be removed from, or are already missing
from, the relationship then the server MUST return a successful response.
  
Note: As described above for POST requests, this approach helps avoid
pointless race conditions between multiple clients making the same changes.
Relationship members are specified in the same way as in the POST request.
In the following example, comments with IDs of 12 and 13 are removed
from the list of comments for the article with ID 1:
DELETE /articles/1/relationships/comments HTTP/1.1
Content-Type: application/vnd.api+json
Accept: application/vnd.api+json
  "data": [
    { "type": "comments", "id": "12" },
    { "type": "comments", "id": "13" }
  
Note: RFC 7231 specifies that a DELETE request may include a body, but
that a server may reject the request. This spec defines the semantics of a
server, and we are defining its semantics for JSON:API.




    

 Responses

 200 OK

If a server accepts an update but also changes the targeted relationship in
other ways than those specified by the request, it MUST return a 200 OK
response and a document that includes the updated relationship data as its
primary data.
A server MAY return a 200 OK response with a document that contains no
primary data if an update is successful and the server does not change the
targeted relationship in ways other than those specified by the request. Other
top-level members, such as meta, could be included in the response document.
 202 Accepted

If a relationship update request has been accepted for processing, but the
processing has not been completed by the time the server responds, the
server MUST return a 202 Accepted status code.
 204 No Content

If an update is successful and the server doesn’t change the targeted
relationship in ways other than those specified by the request, the server
MUST return either a 200 OK status code and response document (as
described above) or a 204 No Content status code with no response document.
  
Note: This is the appropriate response to a POST request sent to a URL
from a to-many relationship link when that relationship already
exists. It is also the appropriate response to a DELETE request sent to a URL
from a to-many relationship link when that relationship does
not exist.
 403 Forbidden

A server MUST return 403 Forbidden in response to an unsupported request
to update a relationship.
 Other Responses

A server MAY respond with other HTTP status codes.
A server MAY include error details with error responses.
A server MUST prepare responses, and a client MUST interpret
responses, in accordance with
HTTP semantics.
 Deleting Resources

A resource can be deleted by sending a DELETE request to the URL
that represents the resource:
DELETE /photos/1 HTTP/1.1
Accept: application/vnd.api+json
 Responses

 200 OK

A server MAY return a 200 OK response with a document that contains no
primary data if a deletion request is successful. Other top-level members, such
as meta, could be included in the response document.
 202 Accepted

If a deletion request has been accepted for processing, but the processing has
not been completed by the time the server responds, the server MUST
return a 202 Accepted status code.
 204 No Content

If a deletion request is successful, the server MUST return either a 200
OK status code and response document (as described above) or a 204 No Content
status code with no response document.
 404 NOT FOUND

A server SHOULD return a 404 Not Found status code if a deletion request fails
due to the resource not existing.
 Other Responses

A server MAY respond with other HTTP status codes.
A server MAY include error details with error responses.
A server MUST prepare responses, and a client MUST interpret
responses, in accordance with
HTTP semantics.
 Query Parameters

 Query Parameter Families

Although “query parameter” is a common term in everyday web development, it is
not a well-standardized concept. Therefore, JSON:API provides its own
definition of a query parameter.
For the most part, JSON:API’s definition coincides with colloquial usage, and its
details can be safely ignored. However, one important consequence of this
definition is that a URL like the following is considered to have two distinct
query parameters:
/?page[offset]=0&page[limit]=10
The two parameters are named page[offset] and page[limit]; there is no
single page parameter.
In practice, however, parameters like page[offset] and page[limit] are
usually defined and processed together, and it’s convenient to refer to them
collectively. Therefore, JSON:API introduces the concept of a query parameter
family.
A “query parameter family” is the set of all query parameters whose name starts
with a “base name”, followed by zero or more instances of empty square brackets
(i.e. []), square-bracketed legal member names, or square-bracketed
dot-separated lists of legal member names. The family is referred to
by its base name.
For example, the filter query parameter family includes parameters named:
filter, filter[x], filter[], filter[x][], filter[][], filter[x][y],
filter[x.y], etc. However, filter[_] is not a valid parameter name in the
family, because _ is not a valid member name.
  
Note: Dot separated lists of legal member names are intended to be used for
relationship paths. For example, this allows filtering strategies using
relationship paths as defined for [sorting][fetching sorting] in query parameters
such as GET /posts?sort=author.name&filter[author.status]=active.
 Extension-Specific Query Parameters

The base name of every query parameter introduced by an extension MUST be
prefixed with the extension’s namespace followed by a colon (:). The
remainder of the base name MUST contain only the characters [a-z] (U+0061
to U+007A, “a-z”).
 Implementation-Specific Query Parameters

Implementations MAY support custom query parameters. However, the names of
these query parameters MUST come from a family
whose base name is a legal member name and also contains at least
one non a-z character (i.e., outside U+0061 to U+007A).
It is RECOMMENDED that a capital letter (e.g. camelCasing) be used to
satisfy the above requirement.
If a server encounters a query parameter that does not follow the naming
conventions above, or the server does not know how to process it as a query
parameter from this specification, it MUST return 400 Bad Request.
  
Note: By forbidding the use of query parameters that contain only the characters
[a-z], JSON:API is reserving the ability to standardize additional query
parameters later without conflicting with existing implementations.
 Errors

 Processing Errors

A server MAY choose to stop processing as soon as a problem is encountered,
or it MAY continue processing and encounter multiple problems. For instance,
a server might process multiple attributes and then return multiple validation
problems in a single response.
When a server encounters multiple problems for a single request, the most
generally applicable HTTP error code SHOULD be used in the response. For
instance, 400 Bad Request might be appropriate for multiple 4xx errors
or 500 Internal Server Error might be appropriate for multiple 5xx errors.
 Error Objects

Error objects provide additional information about problems encountered while
performing an operation. Error objects MUST be returned as an array
keyed by errors in the top level of a JSON:API document.
An error object MAY have the following members, and MUST contain at
least one of:
  
id: a unique identifier for this particular occurrence of the problem.
  
links: a links object that MAY contain the following members:
      
about: a link that leads to further details about this
particular occurrence of the problem. When derefenced, this URI SHOULD
return a human-readable description of the error.
      
type: a link that identifies the type of error that this
particular error is an instance of. This URI SHOULD be dereferencable to
a human-readable explanation of the general error.
  
status: the HTTP status code applicable to this problem, expressed as a
string value.  This SHOULD be provided.
  
code: an application-specific error code, expressed as a string value.
  
title: a short, human-readable summary of the problem that SHOULD NOT
change from occurrence to occurrence of the problem, except for purposes of
localization.
  
detail: a human-readable explanation specific to this occurrence of the
problem. Like title, this field’s value can be localized.
  
source: an object containing references to the primary source of the error.
It SHOULD include one of the following members or be omitted:
      
pointer: a JSON Pointer [RFC6901]
to the value in the request document that caused the error [e.g. "/data"
for a primary data object, or "/data/attributes/title" for a specific
attribute]. This MUST point to a value in the request document that
exists; if it doesn’t, the client SHOULD simply ignore the pointer.
      
parameter: a string indicating which URI query parameter caused
the error.
      
header: a string indicating the name of a single request header which
caused the error.
  
meta: a meta object containing non-standard meta-information about the
error.
 Appendix

 Query Parameters Details

 Parsing/Serialization

A query parameter is a name–value pair extracted from, or serialized into, a
URI’s query string.
To extract the query parameters from a URI, an implementation MUST run the
URI’s query string, excluding the leading question mark, through the
application/x-www-form-urlencoded parsing algorithm,
with one exception: JSON:API allows the specification that defines a query
parameter’s usage to provide its own rules for parsing the parameter’s value
from the value bytes identified in steps 3.2 and and 3.3 of the application/x-www-form-urlencoded
parsing algorithm. The resulting value might not be a string.
  
Note: In general, the query string parsing built in to servers and browsers
will match the process specified above, so most implementations do not need
to worry about this.
  
The application/x-www-form-urlencoded format is referenced because it is
the basis for the a=b&c=d style that almost all query strings use today.
  
However, application/x-www-form-urlencoded parsing contains the bizarre
historical artifact that + characters must be treated as spaces, and it
requires that all values be percent-decoded during parsing, which makes it
impossible to use RFC 3986 delimiter characters
as delimiters. These issues motivate the exception that JSON:API defines above.
Similarly, to serialize a query parameter into a URI, an implementation MUST
use the the application/x-www-form-urlencoded serializer,
with the corresponding exception that a parameter’s value — but not its name —
may be serialized differently than that algorithm requires, provided the
serialization does not interfere with the ability to parse back the resulting URI.
 Square Brackets in Parameter Names

With query parameter families, JSON:API allows for
query parameters whose names contain square brackets (i.e., U+005B “[” and
U+005D “]”).
According to the query parameter serialization rules above, a compliant
implementation will percent-encode these square brackets. However, some URI
producers — namely browsers — do not always encode them. Servers SHOULD
accept requests in which these square brackets are left unencoded in a query
parameter’s name. If a server does accept these requests, it MUST treat the
request as equivalent to one in which the square brackets were percent-encoded.