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OpenAPI Specification

Version 3.0

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

The OpenAPI Specification is licensed under The Apache License, Version 2.0.

Introduction

The OpenAPI Specification is a project used to describe and document RESTful APIs.

The OpenAPI Specification defines a set of files required to describe such an API. These files can then be used by the Swagger-UI project to display the API and Swagger-Codegen to generate clients in various languages. Additional utilities can also take advantage of the resulting files, such as testing tools.

Table of Contents

Revision History

Version Date Notes
2.0 2015-12-31 Donation of Swagger 2.0 to the Open API Initiative
2.0 2014-09-08 Release of Swagger 2.0
1.2 2014-03-14 Initial release of the formal document.
1.1 2012-08-22 Release of Swagger 1.1
1.0 2011-08-10 First release of the Swagger Specification

Definitions

Path Templating

Path templating refers to the usage of curly braces ({}) to mark a section of a URL path as replaceable using path parameters.

Media Types

Media type definitions are spread across several resources. The media type definitions should be in compliance with RFC 6838.

Some examples of possible media type definitions:

  text/plain; charset=utf-8
  application/json
  application/vnd.github+json
  application/vnd.github.v3+json
  application/vnd.github.v3.raw+json
  application/vnd.github.v3.text+json
  application/vnd.github.v3.html+json
  application/vnd.github.v3.full+json
  application/vnd.github.v3.diff
  application/vnd.github.v3.patch
HTTP Status Codes

The HTTP Status Codes are used to indicate the status of the executed operation. The available status codes are initially defined by RFC 7231 and registered status codes are listed in the IANA Status Code Registry.

Specification

Format

The files describing the RESTful API in accordance with the OpenAPI Specification are represented as JSON objects and conform to the JSON standards. YAML, being a superset of JSON, can be used as well to represent a OAS (OpenAPI Specification) file.

For example, if a field is said to have an array value, the JSON array representation will be used:

{
   "field" : [...]
}

While the API is described using JSON it does not impose a JSON input/output to the API itself.

All field names in the specification are case sensitive.

The schema exposes two types of fields. Fixed fields, which have a declared name, and Patterned fields, which declare a regex pattern for the field name. Patterned fields can have multiple occurrences as long as each has a unique name.

In order to preserve the ability to round-trip between YAML and JSON formats, YAML version 1.2 is recommended along with some additional constraints:

  • Tags MUST be limited to those allowed by the JSON Schema ruleset
  • Keys used in YAML maps MUST be limited to a scalar string, as defined by the YAML Failsafe schema ruleset

File Structure

The OAS representation of the API is made of a single file. However, parts of the definitions can be split into separate files, at the discretion of the user. This is applicable for $ref fields in the specification as follows from the JSON Schema definitions.

By convention, the OpenAPI Specification (OAS) file is named openapi.json or openapi.yaml.

Data Types

Primitive data types in the OAS are based on the types supported by the JSON-Schema Draft 4. Models are described using the Schema Object which is a subset of JSON Schema Draft 4.

Primitives have an optional modifier property format. OAS uses several known formats to more finely define the data type being used. However, the format property is an open string-valued property, and can have any value to support documentation needs. Formats such as "email", "uuid", etc., can be used even though they are not defined by this specification. Types that are not accompanied by a format property follow their definition from the JSON Schema. The formats defined by the OAS are:

Common Name type format Comments
integer integer int32 signed 32 bits
long integer int64 signed 64 bits
float number float
double number double
string string
byte string byte base64 encoded characters
binary string binary any sequence of octets
boolean boolean
date string date As defined by full-date - RFC3339
dateTime string date-time As defined by date-time - RFC3339
password string password Used to hint UIs the input needs to be obscured.

Schema

OpenAPI Object

This is the root document object for the API specification. It combines what previously was the Resource Listing and API Declaration (version 1.2 and earlier) together into one document.

Fixed Fields
Field Name Type Description
openapi OpenAPI Version String Required. Specifies the OpenAPI Specification version being used. It can be used by tooling Specifications and clients to interpret the version. The structure shall be major.minor.patch, where patch versions must be compatible with the existing major.minor tooling. Typically patch versions will be introduced to address errors in the documentation, and tooling should typically be compatible with the corresponding major.minor (3.0.*). Patch versions will correspond to patches of this document.
info Info Object Required. Provides metadata about the API. The metadata can be used by the clients if needed.
servers [Server Object] An optional array of Server Objects which provide connectivity information to a target server.
paths Paths Object Required. The available paths and operations for the API.
components Components Object An element to hold various schemas for the specification.
security [Security Requirement Object] A declaration of which security mechanisms can be used across the API. The list of values includes alternative security requirement objects that can be used. Only one of the security requirement objects need to be satisfied to authorize a request. Individual operations can override this definition.
tags [Tag Object] A list of tags used by the specification with additional metadata. The order of the tags can be used to reflect on their order by the parsing tools. Not all tags that are used by the Operation Object must be declared. The tags that are not declared may be organized randomly or based on the tools' logic. Each tag name in the list MUST be unique.
externalDocs External Documentation Object Additional external documentation.

This object can be extended with Specification Extensions.

OpenAPI Version String

The version string signifies the version of the OpenAPI Specification that the document complies to. The format for this string must be major.minor.patch. The patch may be suffixed by a hyphen and extra alphanumeric characters.

A major.minor shall be used to designate the OpenAPI Specification version, and will be considered compatible with the OpenAPI Specification specified by that major.minor version. The patch version will not be considered by tooling, making no distinction between 3.0.0 and 3.0.1.

In subsequent versions of the OpenAPI Specification, care will be given such that increments of the minor version should not interfere with operations of tooling developed to a lower minor version. Thus a hypothetical 3.1.0 specification should be usable with tooling designed for 3.0.0.

Info Object

The object provides metadata about the API. The metadata can be used by the clients if needed, and can be presented in the Swagger-UI for convenience.

Fixed Fields
Field Name Type Description
title string Required. The title of the application.
description string A short description of the application. CommonMark syntax can be used for rich text representation.
termsOfService string A URL to the Terms of Service for the API.
contact Contact Object The contact information for the exposed API.
license License Object The license information for the exposed API.
version string Required Provides the version of the application API (not to be confused with the specification version).

This object can be extended with Specification Extensions.

Info Object Example:
{
  "title": "Swagger Sample App",
  "description": "This is a sample server Petstore server.",
  "termsOfService": "http://swagger.io/terms/",
  "contact": {
    "name": "API Support",
    "url": "http://www.swagger.io/support",
    "email": "support@swagger.io"
  },
  "license": {
    "name": "Apache 2.0",
    "url": "http://www.apache.org/licenses/LICENSE-2.0.html"
  },
  "version": "1.0.1"
}
title: Swagger Sample App
description: This is a sample server Petstore server.
termsOfService: http://swagger.io/terms/
contact:
  name: API Support
  url: http://www.swagger.io/support
  email: support@swagger.io
license:
  name: Apache 2.0
  url: http://www.apache.org/licenses/LICENSE-2.0.html
version: 1.0.1

Contact Object

Contact information for the exposed API.

Fixed Fields
Field Name Type Description
name string The identifying name of the contact person/organization.
url string The URL pointing to the contact information. MUST be in the format of a URL.
email string The email address of the contact person/organization. MUST be in the format of an email address.

This object can be extended with Specification Extensions.

Contact Object Example:
{
  "name": "API Support",
  "url": "http://www.swagger.io/support",
  "email": "support@swagger.io"
}
name: API Support
url: http://www.swagger.io/support
email: support@swagger.io

License Object

License information for the exposed API.

Fixed Fields
Field Name Type Description
name string Required. The license name used for the API.
url string A URL to the license used for the API. MUST be in the format of a URL.

This object can be extended with Specification Extensions.

License Object Example:
{
  "name": "Apache 2.0",
  "url": "http://www.apache.org/licenses/LICENSE-2.0.html"
}
name: Apache 2.0
url: http://www.apache.org/licenses/LICENSE-2.0.html

Server Object

An object representing a Server.

Fixed Fields
Field Name Type Description
url string A URL to the target host. This URL supports template variables and may be relative, to indicate that the host location is relative to the location where the OpenAPI Specification is being served. Templates are optional and specified by the Host Template Parameter syntax. Template substitutions will be made when a variable is named in {brackets}.
description string An optional string describing the host designated by the URL.
templates Templates Object An object holding templates for substitution in the URL template

This object can be extended with Specification Extensions.

Server Object Example

The following shows how multiple hosts can be described in the Server Object array

servers:
- url: https://development.gigantic-server.com/v1
  description: Development server
- url: https://staging.gigantic-server.com/v1
  description: Staging server
- url: https://api.gigantic-server.com/v1
  description: Production server

The following shows how templates an be used for a server configuration

servers:
- url: https://{username}.gigantic-server.com:{port}/{basePath}
  description: The production API server
  templates:
    username:
      # note! no enum here means it is an open value
      default: demo
      description: this value is assigned by the service provider, in this example `gigantic-server.com`
    port:
      enum:
        - 8443
        - 443
      default: 8443
    basePath:
      # open meaning there is the opportunity to use special base paths as assigned by the provider, default is `v2`
      default: v2

Host Templates Object

Patterned Fields
Field Pattern Type Description
[variable name] Host Template Parameter A parameter to be used for substitution in the URL template.

This object can be extended with Specification Extensions.

Host Template

An object representing a Host URL template

Field Name Type Description
enum [Possible Values] An enumeration of primitive type values to be used if the substitution options are from a limited set.
default [Default Value] Required. The default value to use for substitution if an alternate value is not specified, and will be sent if an alternative value is not supplied.
description string An optional description for the template parameter

This object can be extended with Specification Extensions.

Components Object

Holds a set of reusable objects for different aspects of the OAS. All objects defined within the components object will have no effect on the API unless they are explicitly referenced from properties outside the components object.

Fixed Fields
Field Pattern Type Description
Definitions Object A hash containing payload definitions for the specification.
Responses Definitions Object Reusable responses objects.
Parameters Definitions Object An object to hold parameters to be reused across operations. Parameter definitions can be referenced to the ones defined here.
Request Body Definitions Object An object to hold request body definitions to be reused across operations. Request Body definitions can be referenced to the ones defined here.
Response Headers Definitions Object Response headers to reuse across the specification.
Security Definitions Object Security definitions to reuse across the specification.
Link Definitions Object Link definitions to reuse across the specification.
Callback Definitions Object Callback definitions to reuse across the specification.

All the fixed fields declared above are objects that MUST use keys that match the regular expression: [a-zA-Z0-9.\-_]+.

Paths Object

Holds the relative paths to the individual endpoints. The path is appended to the Server Object in order to construct the full URL. The Paths may be empty, due to ACL constraints.

Patterned Fields
Field Pattern Type Description
/{path} Path Item Object A relative path to an individual endpoint. The field name MUST begin with a slash. The path is appended to the Server Object in order to construct the full URL. Path templating is allowed.

This object can be extended with Specification Extensions.

Paths Object Example
{
  "/pets": {
    "get": {
      "description": "Returns all pets from the system that the user has access to",
      "responses": {
        "200": {          
          "description": "A list of pets.",
          "content" : {
            "application/json" : {
              "schema": {
                "type": "array",
                "items": {
                  "$ref": "#/definitions/pet"
                }
              }
            }
          }
        }
      }
    }
  }
}
/pets:
  get:
    description: Returns all pets from the system that the user has access to
    responses:
      '200':
        description: A list of pets.
        content:
          application/json:
            schema:
              type: array
              items:
                $ref: '#/definitions/pet'

Path Item Object

Describes the operations available on a single path. A Path Item may be empty, due to ACL constraints. The path itself is still exposed to the documentation viewer but they will not know which operations and parameters are available.

Fixed Fields
Field Name Type Description
$ref string Allows for an external definition of this path item. The referenced structure MUST be in the format of a Path Item Object. If there are conflicts between the referenced definition and this Path Item's definition, the behavior is undefined.
summary string An optional, string summary, intended to apply to all operations in this path.
description string An optional, string description, intended to apply to all operations in this path.
get Operation Object A definition of a GET operation on this path.
put Operation Object A definition of a PUT operation on this path.
post Operation Object A definition of a POST operation on this path.
delete Operation Object A definition of a DELETE operation on this path.
options Operation Object A definition of a OPTIONS operation on this path.
head Operation Object A definition of a HEAD operation on this path.
patch Operation Object A definition of a PATCH operation on this path.
trace Operation Object A definition of a TRACE operation on this path.
servers Server Object An alternative server array to service all operations in this path.
parameters [Parameter Object | Reference Object] A list of parameters that are applicable for all the operations described under this path. These parameters can be overridden at the operation level, but cannot be removed there. The list MUST NOT include duplicated parameters. A unique parameter is defined by a combination of a name and location. The list can use the Reference Object to link to parameters that are defined at the OpenAPI Object's parameters.

This object can be extended with Specification Extensions.

Path Item Object Example
{
  "get": {
    "description": "Returns pets based on ID",
    "summary": "Find pets by ID",
    "operationId": "getPetsById",
    "responses": {
      "200": {
        "description": "pet response",
        "content": {
          "*": {
            "schema": {
              "type": "array",
              "items": {
                "$ref": "#/definitions/Pet"
              }
            }
          }
        }
      },
      "default": {
        "description": "error payload",
        "content": {
          "text/html" : {
            "schema": {
              "$ref": "#/definitions/ErrorModel"
            }
          }
        }
      }
    }
  },
  "parameters": [
    {
      "name": "id",
      "in": "path",
      "description": "ID of pet to use",
      "required": true,
      "type": "array",
      "items": {
        "type": "string"
      },
      "style": "commaDelimited"
    }
  ]
}
get:
  description: Returns pets based on ID
  summary: Find pets by ID
  operationId: getPetsById
  responses:
    '200':
      description: pet response
      content:
        *:
          schema:
            type: array
            items:
              $ref: '#/definitions/Pet'
    default:
      description: error payload
      content:
        'text/html':
          schema:
            $ref: '#/definitions/ErrorModel'
parameters:
- name: id
  in: path
  description: ID of pet to use
  required: true
  type: array
  format: form
  items:
    type: string

Operation Object

Describes a single API operation on a path.

Fixed Fields
Field Name Type Description
tags [string] A list of tags for API documentation control. Tags can be used for logical grouping of operations by resources or any other qualifier.
summary string A short summary of what the operation does. For maximum readability in the swagger-ui, this field SHOULD be less than 120 characters.
description string A verbose explanation of the operation behavior. CommonMark syntax can be used for rich text representation.
externalDocs External Documentation Object Additional external documentation for this operation.
operationId string Unique string used to identify the operation. The id MUST be unique among all operations described in the API. Tools and libraries MAY use the operationId to uniquely identify an operation, therefore, it is recommended to follow common programming naming conventions.
parameters [Parameter Object | Reference Object] A list of parameters that are applicable for this operation. If a parameter is already defined at the Path Item, the new definition will override it, but can never remove it. The list MUST NOT include duplicated parameters. A unique parameter is defined by a combination of a name and location. The list can use the Reference Object to link to parameters that are defined at the OpenAPI Object's parameters.
requestBody [Request Body Object | Reference Object] The request body applicable for this operation. The requestBody is only supported in HTTP methods where the HTTP 1.1 specification has explicitly defined semantics for request bodies. In other cases where the HTTP spec is vague, requestBody shall be ignored by consumers.
responses Responses Object Required. The list of possible responses as they are returned from executing this operation.
callback responses Callback Responses Object The list of possible callback responses as they are returned from executing this operation.
deprecated boolean Declares this operation to be deprecated. Usage of the declared operation should be refrained. Default value is false.
security [Security Requirement Object] A declaration of which security mechanisms can be used for this operation. The list of values includes alternative security requirement objects that can be used. Only one of the security requirement objects need to be satisfied to authorize a request. This definition overrides any declared top-level security. To remove a top-level security declaration, an empty array can be used.
servers Server Object An alternative server array to service this operation. If an alternative server object is specified at the Path Item Object or Root level, it will be overridden by this value.

This object can be extended with Specification Extensions.

Operation Object Example
{
  "tags": [
    "pet"
  ],
  "summary": "Updates a pet in the store with form data",
  "description": "",
  "operationId": "updatePetWithForm",
  "parameters": [
    {
      "name": "petId",
      "in": "path",
      "description": "ID of pet that needs to be updated",
      "required": true,
      "type": "string"
    }
  ],
  "requestBody" : {
    "content": {
      "application/x-www-form-urlencoded": {
        "schema": {
          "type": "object",
           "properties": {
              "name": { 
                "description": "Updated name of the pet",
                "type": "string"
              },
              "status": {
                "description": "Updated status of the pet",
                "type": "string"
             }
           },
        "required": ["status"] 
        }
      }
    }
  },
  "responses": {
    "200": {
      "description": "Pet updated.",
      "content" : {
        "application/json" : {},
        "application/xml" : {}
      }
    },
    "405": {
      "description": "Invalid input",
      "content" : {
        "application/json" : {},
        "application/xml" : {}
      }
    }
  },
  "security": [
    {
      "petstore_auth": [
        "write:pets",
        "read:pets"
      ]
    }
  ]
}
tags:
- pet
summary: Updates a pet in the store with form data
description: ''
operationId: updatePetWithForm
parameters:
- name: petId
  in: path
  description: ID of pet that needs to be updated
  required: true
  type: string
requestBody:
  content:
    'application/x-www-form-urlencoded':
      schema:
       properties:
          name: 
            description: Updated name of the pet
            type: string
          status:
            description: Updated status of the pet
            type: string
        required: 
          - status
responses:
  '200':
    description: Pet updated.
    content: 
      'application/json': {}
      'application/xml': {}
  '405':
    description: Invalid input
    content: 
      'application/json': {}
      'application/xml': {}
security:
- petstore_auth:
  - write:pets
  - read:pets

External Documentation Object

Allows referencing an external resource for extended documentation.

Fixed Fields
Field Name Type Description
description string A short description of the target documentation. CommonMark syntax can be used for rich text representation.
url string Required. The URL for the target documentation. Value MUST be in the format of a URL.

This object can be extended with Specification Extensions.

External Documentation Object Example
{
  "description": "Find more info here",
  "url": "https://swagger.io"
}
description: Find more info here
url: https://swagger.io

Parameter Object

Describes a single operation parameter.

A unique parameter is defined by a combination of a name and location.

There are four possible parameter types.

  • Path - Used together with Path Templating, where the parameter value is actually part of the operation's URL. This does not include the host or base path of the API. For example, in /items/{itemId}, the path parameter is itemId.
  • Query - Parameters that are appended to the URL. For example, in /items?id=###, the query parameter is id.
  • Header - Custom headers that are expected as part of the request.
  • Cookie - Used to pass a specific cookie value to the API.
Fixed Fields
Field Name Type Description
name string Required. The name of the parameter. Parameter names are case sensitive.
  • If in is "path", the name field MUST correspond to the associated path segment from the path field in the Paths Object. See Path Templating for further information.
  • For all other cases, the name corresponds to the parameter name used based on the in property.
in string Required. The location of the parameter. Possible values are "query", "header", "path" or "cookie".
description string A brief description of the parameter. This could contain examples of use. CommonMark syntax can be used for rich text representation.
required boolean Determines whether this parameter is mandatory. If the parameter is in "path", this property is required and its value MUST be true. Otherwise, the property MAY be included and its default value is false.
deprecated boolean Specifies that a parameter is deprecated and should be transitioned out of usage.
allowEmptyValue boolean Sets the ability to pass empty-valued parameters. This is valid only for query parameters and allows you to send a parameter with a name only or an empty value. Default value is false.

The rules for serialization of the parameter are specified in one of two ways. For simpler scenarios, a Style and Schema can be used to describe the structure and syntax of the parameter.

Field Name Type Description
style string Describes how the parameter value will be serialized depending on type of the parameter value.
explode boolean When this is true, parameter values of type array or object generate seperate parameters for each value of the array, or key-value-pair of the map. For other types of parameters this property has no effect. The default value is false.
allowReserved boolean Determines whether the parameter value should allow reserved characters, as defined by RFC3986 :/?#[]@!$&'()*+,;= to be included without percent-encoding. This property only applies to parameters with an in value of query. The default value is false.
schema Schema Object The schema defining the type used for the parameter.

For more complex scenarios a content object can be used to define the media-type and schema of the parameter.

Field Name Type Description
content Content Object The content of the request body.

In order to support common ways of serializing simple parameters, a set of style values are defined.

style type in Comments
matrix primitive, array, object path Path-style parameters defined by RFC6570
label primitive, array, object path Label style parameters defined by RFC6570
form primitive, array, object query Form style parameters defined by RFC6570
commaDelimited array query, path Comma seperated array values. This option replaces collectionFormat equal to csv.
spaceDelimited array query Space seperated array values. This option replaces collectionFormat equal to ssv.
pipeDelimited array query Pipe seperated array values. This option replaces collectionFormat equal to pipes.
deepObject object query Provides a simple way of rendering nested objects using form parameters.
Style Examples

Assuming a parameter named color with one of the following values:

   string -> "blue"
   array -> ["blue","black","brown"]
   object -> { "R" : 100, "G" :200, "B" : 150 }

The following table shows examples of how those values would be rendered.

style explode empty string array object
matrix false ;color ;color=blue ;color=blue,black,brown ;color=R,100,G,200,B,150
matrix true ;color ;color=blue ;color=blue;color=black;color=brown ;R=100;G=200;B=150
label false . .blue .blue.black.brown .R.100.G.200.B.150
label true . .blue .blue.black.brown .R=100.G=200.B=150
form false color= color=blue color=blue,black,brown color=R,100,G,200,B,150
form true color= color=blue color=blue&color=black&color=brown R=100&G=200&B=150
commaDelimited false n/a n/a blue,black,brown R,100,G,200,B,150
spaceDelimited false n/a n/a blue%20black%20brown R%20100%20G%20200%20B%20150
pipeDelimited false n/a n/a blue|black|brown R|100|G|200
deepObject true n/a n/a n/a color[R]=100&color[G]=200&color[B]=150

This object can be extended with Specification Extensions.

Parameter Object Examples

A header parameter with an array of 64 bit integer numbers:

{
  "name": "token",
  "in": "header",
  "description": "token to be passed as a header",
  "required": true,
  "schema": {
    "type": "array",
    "items": {
      "type": "integer",
      "format": "int64"
    }
  },
  "style": "commaDelimited"
}
name: token
in: header
description: token to be passed as a header
required: true
schema:
  type: array
  items:
    type: integer
    format: int64
style: commaDelimited

A path parameter of a string value:

{
  "name": "username",
  "in": "path",
  "description": "username to fetch",
  "required": true,
  "schema": {
    "type": "string"
  }
}
name: username
in: path
description: username to fetch
required: true
schema:
  type: string

An optional query parameter of a string value, allowing multiple values by repeating the query parameter:

{
  "name": "id",
  "in": "query",
  "description": "ID of the object to fetch",
  "required": false,
  "schema": {
    "type": "array",
    "items": {
      "type": "string"
    }
  },
  "style": "form",
  "explode": true
}
name: id
in: query
description: ID of the object to fetch
required: false
schema:
  type: array
  items:
    type: string
style: form
explode: true

Request Body Object

Describes a single request body.

Fixed Fields
Field Name Type Description
description string A brief description of the request body. This could contain examples of use. CommonMark syntax can be used for rich text representation.
content Content Object The content of the request body.
required boolean Determines if the request body is required in the request. Defaults to true.
Patterned Fields
Field Pattern Type Description
* Schema Object The schema defining the request body.
^x- Any Allows extensions to the OpenAPI Schema. The field name MUST begin with x-, for example, x-internal-id. The value can be null, a primitive, an array or an object. See Vendor Extensions for further details.
Request Body Examples

A request body with a referenced model definition.

{
  "description": "user to add to the system",
  "content" : {
    "application/json" : {
      "schema": {
          "$ref": "#/definitions/User"
        },
      "examples": [
        { "$ref": 'http://foo.bar#/examples/address-example.json'}
      ]
    },
    "application/xml" : {
       "schema": {
        "$ref": "#/definitions/User"
      },
      "examples": [
        { "$ref": 'http://foo.bar#/examples/address-example.xml'}
      ]
    },
    "text/plain" : {
      "examples": [
        { "$ref": 'http://foo.bar#/examples/address-example.txt'}
      ]
    },
    "*": {
      "example": {
        $ref: "http://foo.bar#/examples/address-example.whatever"
      }
  }
}
description: user to add to the system
content: 
  'application/json':
    schema:
      $ref: '#/definitions/User'
    examples:
      - 'http://foo.bar/examples/user-example.json'
  'application/xml':
    schema:
      $ref: '#/definitions/User'
    examples:
      - 'http://foo.bar/examples/user-example.xml'
  'text/plain':
    examples:
      - 'http://foo.bar/examples/user-example.txt'
  '*':
    schema:
      $ref: 'http://foo.bar/examples/user-example.whatever'

A body parameter that is an array of string values:

{
  "description": "user to add to the system",
  "content": {
    "text/plain": {
      "schema": {
        "type": "array",
        "items": {
          "type": "string"
        }
      }
    }
  }
}
description: user to add to the system
required: true
content:
  text/plain:
    schema:
      type: array
      items:
        type: string

Content Object

Describes a set of supported content types. A content object can be used in requestBody and response objects.

Each key in the content object is the media-type of the Content Type Object.

Content Examples
"content" : {
  "application/json": {
    "schema": {
      "type": "array",
      "items": {
        "type": "string"
      }
    },
    "examples": [
      ["Bob","Diane","Mary","Bill"],
      []
     ]
  },
  "application/xml" : {
    "examples" : [
      "<Users><User name='Bob'/><User name='Diane'/><User name='Mary'/><User name='Bill'/></Users>",
      "<Users/>"
    ]
  },
  "text/plain" : {
    "Bob,Diane,Mary,Bill",
    ""
  }
}
content:
  'application/json': 
    schema:
      type: array
      items:
        type: string
    examples:
      - 
        - Bob
        - Diane
        - Mary
        - Bill
      - {}

  'application/xml': 
    examples:
      - "<Users><User name='Bob'/><User name='Diane'/><User name='Mary'/><User name='Bill'/></Users>"
      - "<Users/>"
  'text/plain':
    examples:
      - "Bob,Diane,Mary,Bill"

Content Type Object

Each content type object provides schema and examples for a the media type identified by its key. Content Type objects can be used in a content object.

Fixed Fields
Field Name Type Description
schema Schema Object The schema defining the type used for the request body.
examples Examples Array Examples of the content type.
example Example Object Example of the content type.
Patterned Fields
Field Pattern Type Description
^x- Any Allows extensions to the OpenAPI Schema. The field name MUST begin with x-, for example, x-internal-id. The value can be null, a primitive, an array or an object. See Vendor Extensions for further details.
Content Type Examples

A content type description.

{
  "application/json": {
    "schema": {
         "$ref": "#/definitions/Pet"
    },
    "examples": [{
                  "name" : "Fluffy",
                  "petType" : "Cat"
                 },
                 { 
                   "name" : "Rover",
                   "petType" : "Frog"
                 }]
  }
}
application/json: 
  schema:
    $ref: "#/definitions/Pet"
  examples:
    - name: Fluffy
      petType: Cat
    - name: Rover
      petType: Frog
Considerations for file uploads

In contrast with the 2.0 specification, describing file input/output content in OpenAPI is described with the same semantics as any other schema type. Specifically:

# content transferred with base64 encoding
schema:
  type: string
  format: base64

# content transfered in binary (octet-stream):
schema:
  type: string
  format: binary

Note that the above examples apply to either input payloads (i.e. file uploads) or response payloads.

A requestBody example for submitting a file in a POST operation therefore may look like the following:

requestBody:
  # any media type is accepted, functionally equivalent to `*/*`
  application/octet-stream:
    content:
      schema:
        # a binary file of any type
        type: string
        format: binary

In addition, specific media types may be specified:

# multiple, specific media types may be specified:
requestBody:
  # a binary file of type png or jpeg
  content:
    'image/png, image/jpeg':
      schema:
        type: string
        format: binary
Support for x-www-form-urlencoded request bodies

To submit content using form url encoding via RFC 1866, the following definition may be used:

requestBody:
  content:
    x-www-form-urlencoded:
      schema:
        type: object
        properties:
          id:
            type: string
            format: uuid
          address:
            # complex types are stringified to support rfc1866
            type: object
            properties: {}

Note that in the above example, the contents in the requestBody must be stringified per RFC1866 when being passed to the server. In addition, the address field complex object will be strigified as well.

When passing complex objects in the x-www-form-urlencoded content type, the default serialization strategy of such properties is described in the parameterContent section as deepObject.

Special Considerations for mutlipart content

It is common to use multipart/form-data as a Content-Type when transferring request bodies to operations. In contrast to 2.0, a schema is required to define the input parameters to the operation when using multipart content. This allows complex structures as well as supports mechanisms for multiple file uploads.

When passing in multipart types, boundaries may be used to separate sections of the content being transferred--thus, the following default Content-Types are defined for multipart/*:

  • If the property is a primitive, or an array of primitive values, the default Content-Type is text/plain
  • If the property is complex, or an array of complex values, the default Content-Type is application/json
  • If the property is a type: string with format: binary or format: base64 (aka a file object), the default Content-Type is application/octet-stream

Examples:

requestBody:
  content:
    multipart/form-data:
      schema:
        type: object
        properties:
          id:
            type: string
            format: uuid
          address:
            # default Content-Type for objects is `application/json`
            type: object
            properties: {}
          profileImage:
            # default Content-Type for string/binary is `application/octet-stream`
            type: string
            format: binary
          children:
            # default Content-Type for arrays is based on the `inner` type (text/plain here)
            type: array
            items:
              type: string
          addresses:
            # default Content-Type for arrays is based on the `inner` type (object shown, so `application/json` in this example)
            type: array
            items:
              type: '#/definitions/Address'

In scenarios where more control is needed over the Content-Type for multipart request bodies, an encoding attribute is introduced. This attribute is only applicable to mulitpart/* and x-www-form-urlencoded request bodies.

Encoding Object

An object representing multipart region encoding for requestBody objects

Patterned Fields
Field Pattern Type Description
The property to apply encoding to Encoding Property | Encoding The field name to apply special encoding attributes to. This field must exist in the schema as a property.

Encoding

A single encoding definition applied to a single schema property

Fixed Fields
Field Name Type Description
contentType string Required. The content-type to use for encoding a specific property.
Headers object A string map allowing additional information to be provided as headers, for example Content-Disposition. Note Content-Type is described separately and will be ignored from this section.
Style string The content-type to use for encoding a specific property. See (#parameterContent) for details on the style property
explode boolean When this is true, property values of type array or object generate seperate parameters for each value of the array, or key-value-pair of the map. For other types of properties this property has no effect. The default value is false.

This object can be extended with Specification Extensions.

Encoding Object Examples
requestBody:
  content:
    multipart/mixed:
      schema:
        type: object
        properties:
          id:
            # default is text/plain
            type: string
            format: uuid
          address:
            # default is application/json
            type: object
            properties: {}
          historyMetadata:
            # need to declare XML format!
            description: metadata in XML format
            type: object
            properties: {}
          profileImage:
            # default is application/octet-stream, need to declare an image type only!
            type: string
            format: binary
encoding:
  historyMetadata:
    # require XML content-type in utf-8 encoding
    contentType: application/xml; charset=utf-8
  profileImage:
    # only accept png/jpeg
    contentType: image/png, image/jpeg

Items Object

A limited subset of JSON-Schema's items object. It is used by parameter definitions.

Fixed Fields
Field Name Type Description
type string Required. The internal type of the array. The value MUST be one of "string", "number", "integer", "boolean", or "array". Files and models are not allowed.
format string The extending format for the previously mentioned type. See Data Type Formats for further details.
items Items Object Required if type is "array". Describes the type of items in the array.
collectionFormat string Determines the format of the array if type array is used. Possible values are:
  • csv - comma separated values foo,bar.
  • ssv - space separated values foo bar.
  • tsv - tab separated values foo\tbar.
  • pipes - pipe separated values foo|bar.
Default value is csv.
default * Declares the value of the item that the server will use if none is provided. (Note: "default" has no meaning for required items.) See http://json-schema.org/latest/json-schema-validation.html#anchor101. Unlike JSON Schema this value MUST conform to the defined type for the data type.
maximum number See http://json-schema.org/latest/json-schema-validation.html#anchor17.
exclusiveMaximum boolean See http://json-schema.org/latest/json-schema-validation.html#anchor17.
minimum number See http://json-schema.org/latest/json-schema-validation.html#anchor21.
exclusiveMinimum boolean See http://json-schema.org/latest/json-schema-validation.html#anchor21.
maxLength integer See http://json-schema.org/latest/json-schema-validation.html#anchor26.
minLength integer See http://json-schema.org/latest/json-schema-validation.html#anchor29.
pattern string See http://json-schema.org/latest/json-schema-validation.html#anchor33.
maxItems integer See http://json-schema.org/latest/json-schema-validation.html#anchor42.
minItems integer See http://json-schema.org/latest/json-schema-validation.html#anchor45.
uniqueItems boolean See http://json-schema.org/latest/json-schema-validation.html#anchor49.
enum [*] See http://json-schema.org/latest/json-schema-validation.html#anchor76.
multipleOf number See http://json-schema.org/latest/json-schema-validation.html#anchor14.

This object can be extended with Specification Extensions.

Items Object Examples

Items must be of type string and have the minimum length of 2 characters:

{
    "type": "string",
    "minLength": 2
}
type: string
minLength: 2

An array of arrays, the internal array being of type integer, numbers must be between 0 and 63 (inclusive):

{
  "type": "array",
  "items": {
    "type": "integer",
    "minimum": 0,
    "maximum": 63
  }
}
type: array
items:
  type: integer
  minimum: 0
  maximum: 63

Responses Object

A container for the expected responses of an operation. The container maps a HTTP response code to the expected response. It is not expected from the documentation to necessarily cover all possible HTTP response codes, since they may not be known in advance. However, it is expected from the documentation to cover a successful operation response and any known errors.

The default MAY be used as a default response object for all HTTP codes that are not covered individually by the specification.

The Responses Object MUST contain at least one response code, and it SHOULD be the response for a successful operation call.

Fixed Fields
Field Name Type Description
default Response Object | Reference Object The documentation of responses other than the ones declared for specific HTTP response codes.
It can be used to cover undeclared responses.
Reference Object can be used to link to a response that is defined at the OpenAPI Object's responses section.
Patterned Fields
Field Pattern Type Description
HTTP Status Code Response Object | Reference Object Any HTTP status code can be used as the property name (one property per HTTP status code). Describes the expected response for that HTTP status code. Reference Object can be used to link to a response that is defined at the OpenAPI Object's responses section. This field must quoted for compatibility between JSON and YAML (i.e. "200"), and may contain the uppercase character, X to designate a wildcard, such as 2XX to represent all response codes between [200-299].

This object can be extended with Specification Extensions.

Responses Object Example

A 200 response for successful operation and a default response for others (implying an error):

{
  "200": {
    "description": "a pet to be returned",
    "content" : {
      "application/json" : {
        "schema": {
          "$ref": "#/definitions/Pet"
        }
      }
    }
  },
  "default": {
    "description": "Unexpected error",
    "content" : {
      "application/json" : {
        "schema": {
          "$ref": "#/definitions/ErrorModel"
        }
      }
    }
  }
}
'200':
  description: a pet to be returned
  content: 
    application/json:
      schema:
        $ref: '#/definitions/Pet'
default:
  description: Unexpected error
  content:
    application/json:
      schema:
        $ref: '#/definitions/ErrorModel'

Response Object

Describes a single response from an API Operation, including design-time, static links to operations based on the response.

Fixed Fields
Field Name Type Description
description string Required. A short description of the response. CommonMark syntax can be used for rich text representation.
headers Headers Object A list of headers that are sent with the response.
content Content Object An object containing descriptions of potential response payloads.
links Links Object An object representing operations related to the response payload.
Patterned Objects
Field Pattern Type Description
* Schema Object| Reference Object A schema describing the response value for a specific Content-Type

Representations may take the form of a wildcard (*) to designate any Content-Type, or a regular expression for matching a specific type

This object can be extended with Specification Extensions.

Response Object Examples

Response of an array of a complex type:

{
  "description": "A complex object array response",
  "content" : {
    "application/json" : {
      "schema": {
        "type": "array",
        "items": {
          "$ref": "#/definitions/VeryComplexType"
        }
      }
    }
  }
}
description: A complex object array response
content: 
  application/json:
    schema: 
      type: array
      items:
        $ref: '#/definitions/VeryComplexType'

Response with a string type:

{
  "description": "A simple string response",
  "content" : {
    "text/plain" : {
      "schema": {
        "type": "string"
      }
    }
  }

}
description: A simple string response
representations:
  text/plain:
    schema:
      type: string

Response with headers:

{
  "description": "A simple string response",
  "content" : {
    "text/plain": {
      "schema": {
        "type": "string"
      }
    }
  },
  "headers": {
    "X-Rate-Limit-Limit": {
      "description": "The number of allowed requests in the current period",
      "type": "integer"
    },
    "X-Rate-Limit-Remaining": {
      "description": "The number of remaining requests in the current period",
      "type": "integer"
    },
    "X-Rate-Limit-Reset": {
      "description": "The number of seconds left in the current period",
      "type": "integer"
    }
  }
}
description: A simple string response
content:
  text/plain:
    schema:
      type: string
    example: 'whoa!'
headers:
  X-Rate-Limit-Limit:
    description: The number of allowed requests in the current period
    type: integer
  X-Rate-Limit-Remaining:
    description: The number of remaining requests in the current period
    type: integer
  X-Rate-Limit-Reset:
    description: The number of seconds left in the current period
    type: integer

Response with no return value:

{
  "description": "object created"
}
description: object created

Callback Object

A container for possible out-of band callbacks from an operation. A callback may be returned from an operation, calling back to the path specified in the operation object.

Patterned Fields
Field Pattern Type Description
Callback name Callback Operation Object | Operation Object An operation object used to define a callback payload structure

This object can be extended with Specification Extensions.

Callback Object Example

A callback to the URL specified by the url parameter in the request

myWebhook:
  '$request.url':
    post:
      body:
        name: postResponse
        schema:
          $ref: '#/definitions/SomePayload'
      responses:
        200:
          description: webhook successfully processed an no retries will be performed

Headers Object

Lists the headers that can be sent as part of a response.

Patterned Fields
Field Pattern Type Description
{name} Header Object The name of the property corresponds to the name of the header. The value describes the type of the header.
Headers Object Example

Rate-limit headers:

{
    "X-Rate-Limit-Limit": {
        "description": "The number of allowed requests in the current period",
        "type": "integer"
    },
    "X-Rate-Limit-Remaining": {
        "description": "The number of remaining requests in the current period",
        "type": "integer"
    },
    "X-Rate-Limit-Reset": {
        "description": "The number of seconds left in the current period",
        "type": "integer"
    }
}
X-Rate-Limit-Limit:
  description: The number of allowed requests in the current period
  type: integer
X-Rate-Limit-Remaining:
  description: The number of remaining requests in the current period
  type: integer
X-Rate-Limit-Reset:
  description: The number of seconds left in the current period
  type: integer

Examples Object

Allows sharing examples for operation requests and responses.

Patterned Fields
Field Pattern Type Description
{media type} Any The name of the property MUST be one of the Operation produces values (either implicit or inherited). The value SHOULD be an example of what such a response would look like.
Examples Array Example

Example representation for application/json media type of a Pet data type:

[
  {
    "name": "Puma",
    "type": "Dog",
    "color": "Black",
    "gender": "Female",
    "breed": "Mixed"
  }
]
-
  name: Puma
  type: Dog
  color: Black
  gender: Female
  breed: Mixed

Links Object

The links object represents a set of possible design-time links for a response. The presence of a link does not guarantee the caller's ability to successfully call invoke it, rather it provides a known relationship and traversal mechanism between responses and other operations.

As opposed to dynamic links--that is, links provided in the response payload, the OAS linking mechanism does not require that link information be provided in a specific response format at runtime.

For computing links, and providing instructions to execute them, a mechanism is defined for accessing values in a response and using them as variables while invoking the linked operation.

Field Name Type Description
$ref string If present, a reference to another Links Object. Note, the presence of $ref in the Links Object will cause all Patterned Objects to be ignored.
Field Pattern Type Description
link name Link Object A short name for the link, following the naming constraints of the definitions name.
The link shall reference a single Link Object, or a JSON Reference to a single link object

Link Object

The Link Object is responsible for defining a possible operation based on a single response.

Field Name Type Description
href url a relative or absolute URL to a linked resource. This field is mutually exclusive with the operationId field.
operationId string the name of an existing, resolvable OAS operation, as defined with a unique operationId. This field is mutually exclusive with the href field. Relative href values may be used to locate an existing Operation Object in the OAS.
parameters Link Parameters Object an Object representing parameters to pass to an operation as specified with operationId or identified via href.
headers Link Headers Object an Object representing headers to pass to the linked resource.
description string a description of the link, supports CommonMark syntax.

This object can be extended with Specification Extensions.

Locating a linked resource may be performed by either a href or operationId. In the case of an operationId, it must be unique and resolved in the scope of the OAS document. Because of the potential for name clashes, consider the href syntax as the preferred method for specifications with external references.

Response Payload Values

Payload values are only available in parseable response payloads which match the advertised media-type. In all cases, if a value does not exist, the parameter will be considered a null value (as opposed to an empty value) and not passed as a parameter to the linked resource. In cases where a value is required, and a parameter is not supplied, the client may choose to not follow the link definition.

Example

Response payload:

{
    "id": "df71a505-07bc-458a-a5c0-73c0340d1ec7",
    "firstname": "Ash",
    "lastname": "Williams"
}

Payload Variables:

id: df71a505-07bc-458a-a5c0-73c0340d1ec7
firstname: Ash
lastname: Williams
missingValue: null

In situations where variables appear in an array, an array of variables will be extracted. For example:

[
  { "color": "red" },
  { "color": "green" },
  { "color": "blue" }
]

will be extracted as such:

color: ["red", "green", "blue"]

The variables generated can be used in locations prescribed by the definition.

Variable substitution

In all cases, variables from request and responses may be substituted for link generation. The table below designates the source of the substitution value and the syntax for accessing it:

Source Location reference identifier example value example reference notes
HTTP Method $method /users/{$method} The allowable values for the $method will be those for the HTTP operation
Requested content type $accepts /users/3?format={$accepts}
Request parameter $request /users/{$request.id} Request parameters must be declared in the parameters section for the operation or they cannot be used in substitution. This includes request headers
Request body $requestBody /users/{$requestBody.user.uuid} For operations which accept payloads, references may be made to portions of the requestBody or the entire body itself
Request URL $url /track?url={$url}
Response value $response {$response.uuid} Only the payload in the response can be accessed with the $response syntax
Response header $responseHeader {$responseHeader.Server} Single header values only are available.

From the request, the parameters used in calling the operation are made available through the $request syntax. For responses, the response payload may be used with the $response syntax. For both requests and responses, values will be substituted in the link in sections designated with the $request or $response keyword, surrounded by curly brackets {}.

Request parameter example

Computing a link from a request operation like such:

paths:
  /users/{id}:
    parameters:
    - name: id
      in: path
      required: true
      description: the user identifier, as userId or username
      schema:
        type: string
    responses:
      200:
        description: the user being returned
        content:
          application/json:
            schema:
              type: object
              properties:
                uuid: the unique user id
                  type: string
                  format: uuid

Can be used in a link like this:

Addresses:
  href: '/users/{$request.id}/department'

Where the $request.id is the value passed in the request to /users/{id}. For a id value of 10101110, the generated link would be:

href: '/users/10101110/department'

Response payload example

Addresses:
  href: '/users/{$response.uuid}/address'

Where the $response.uuid from the example above would yield the target:

href: '/users/df71a505-07bc-458a-a5c0-73c0340d1ec7/address'

And the array example:

ColorSelection:
  href: 'http://colors.my-server.com/colors/{$response.color}'

Would produce the following links:

href: 'http://colors.my-server.com/colors/red'
href: 'http://colors.my-server.com/colors/green'
href: 'http://colors.my-server.com/colors/blue'

As with all links, it at the the clients' discretion to follow them, and permissions and the ability to make a successful call to that link is not guaranteed solely by the existence of a relationship.

Example

The example below shows how relationships in the BitBucket API can be represented with the proposed OAI link scheme. This example uses operationId values to link responses to possible operations.

paths: 
  /2.0/users/{username}: 
    get: 
      operationId: getUserByName
      parameters: 
      - name: username
        type: string
        in: path
        required: true
      responses: 
        200: 
          description: The User
          content:
            application/json:
              schema: 
                $ref: '#/components/definitions/user'
          links:
            userRepositories:
              $ref: '#/components/links/UserRepositories'
  /2.0/repositories/{username}:
    get:
      operationId: getRepositoriesByOwner
      parameters:
        - name: username
          type: string
          in: path
          required: true
      responses:
        200:
          description: repositories owned by the supplied user
          content: 
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/definitions/repository'
          links:
            userRepository:
              $ref: '#/components/links/UserRepository'
  /2.0/repositories/{username}/{slug}: 
    get: 
      operationId: getRepository
      parameters: 
        - name: username
          type: string
          in: path
          required: true
        - name: slug
          type: string
          in: path
          required: true
      responses: 
        200:
          description: The repository
            content:
              application/json: 
                schema: 
                  $ref: '#/components/definitions/repository'
          links:
            repositoryPullRequests:
              $ref: '#/components/links/RepositoryPullRequests'
  /2.0/repositories/{username}/{slug}/pullrequests: 
    get: 
      operationId: getPullRequestsByRepository
      parameters: 
      - name: username
        type: string
        in: path
        required: true
      - name: slug
        type: string
        in: path
        required: true
      - name: state
        type: string
        in: query
        enum: 
          - open
          - merged
          - declined
      responses: 
        200: 
          description: an array of pull request objects
          content:
            application/json: 
              schema: 
                type: array
                items: 
                  $ref: '#/components/definitions/pullrequest'
  /2.0/repositories/{username}/{slug}/pullrequests/{pid}: 
    get: 
      operationId: getPullRequestsById
      parameters: 
      - name: username
        type: string
        in: path
        required: true
      - name: slug
        type: string
        in: path
        required: true
      - name: pid
        type: string
        in: path
        required: true
      responses: 
        200: 
          description: a pull request object
          content:
            application/json: 
            schema: 
              $ref: '#/components/definitions/pullrequest'
          links:
            $ref: '#/components/links/PullRequestMerge'
  /2.0/repositories/{username}/{slug}/pullrequests/{pid}/merge: 
    post: 
      operationId: mergePullRequest
      parameters: 
      - name: username
        type: string
        in: path
        required: true
      - name: slug
        type: string
        in: path
        required: true
      - name: pid
        type: string
        in: path
        required: true
      responses: 
        204:
          description: the PR was successfully merged
components:
  links:
    UserRepositories:
      # returns array of '#/components/definitions/repository'
      operationId: getRepositoriesByOwner
      parameters:
        username: $response.username
    UserRepository:
      # returns '#/components/definitions/repository'
      operationId: getRepository
      parameters:
        username: $response.owner.username
        slug: $response.slug
    RepositoryPullRequests:
      # returns '#/components/definitions/pullrequest'
      operationId: getPullRequestsByRepository
        params: 
          username: $response.owner.username
          slug: $response.slug
    PullRequestMerge:
      # executes /2.0/repositories/{username}/{slug}/pullrequests/{pid}/merge
      operationId: mergePullRequest
      parameters:
        username: $response.user.username # Should be $response.author.username?
        slug: $response.repository.slug
        pid: $response.id
  definitions: 
    user: 
      type: object
      properties: 
        username: 
          type: string
        uuid: 
          type: string
    repository: 
      type: object
      properties: 
        slug: 
          type: string
        owner: 
          $ref: '#/components/definitions/user'
    pullrequest: 
      type: object
      properties: 
        id: 
          type: integer
        title: 
          type: string
        repository: 
          $ref: '#/components/definitions/repository'
        author: 
          $ref: '#/components/definitions/user'

As references to operationId may not be possible (the operationId is an optional value), references may also be made through a relative href:

components:
  links:
    UserRepositories:
      # returns array of '#/components/definitions/repository'
      href: '/2.0/repositories/{$response.username}'

or an absolute href:

components:
  links:
    UserRepositories:
      # returns array of '#/components/definitions/repository'
      href: 'https://na2.gigantic-server.com/2.0/repositories/{$response.username}'

Link Parameters

Using the operationId to reference an operation in the definition has many benefits, including the ability to define media-type options, security requirements, response and error payloads. Many operations require parameters to be passed, and these may be dynamic depending on the response itself.

To specify parameters required by the operation, we can use a Link Parameters Object. This object contains parameter names along with static or dynamic values:

paths:
  /user/{username}: # ...
  /user/{username}/commits:
    get:
      operationId: userCommitHistory
      parameters:
      - name: username
        in: path
        type: string
        required: true
      - name: page
        type: integer
        format: int32
        required: true
      responses: { ... }
components:
  links:
    UserCommitHistory:
      operationId: userCommitHistory
      parameters:
        username: $response.user.username
        page: 0

In the above, the link for UserCommitHistory points to the operation getUserCommitHistory, and passes the username value from the response payload as well as the static scalar value 0.

Header Object

Field Name Type Description
description string A short description of the header.
type string Required. The type of the object. The value MUST be one of "string", "number", "integer", "boolean", or "array".
format string The extending format for the previously mentioned type. See Data Type Formats for further details.
items Items Object Required if type is "array". Describes the type of items in the array.
collectionFormat string Determines the format of the array if type array is used. Possible values are:
  • csv - comma separated values foo,bar.
  • ssv - space separated values foo bar.
  • tsv - tab separated values foo\tbar.
  • pipes - pipe separated values foo|bar.
Default value is csv.
default * Declares the value of the header that the server will use if none is provided. (Note: "default" has no meaning for required headers.) See http://json-schema.org/latest/json-schema-validation.html#anchor101. Unlike JSON Schema this value MUST conform to the defined type for the header.
maximum number See http://json-schema.org/latest/json-schema-validation.html#anchor17.
exclusiveMaximum boolean See http://json-schema.org/latest/json-schema-validation.html#anchor17.
minimum number See http://json-schema.org/latest/json-schema-validation.html#anchor21.
exclusiveMinimum boolean See http://json-schema.org/latest/json-schema-validation.html#anchor21.
maxLength integer See http://json-schema.org/latest/json-schema-validation.html#anchor26.
minLength integer See http://json-schema.org/latest/json-schema-validation.html#anchor29.
pattern string See http://json-schema.org/latest/json-schema-validation.html#anchor33.
maxItems integer See http://json-schema.org/latest/json-schema-validation.html#anchor42.
minItems integer See http://json-schema.org/latest/json-schema-validation.html#anchor45.
uniqueItems boolean See http://json-schema.org/latest/json-schema-validation.html#anchor49.
enum [*] See http://json-schema.org/latest/json-schema-validation.html#anchor76.
multipleOf number See http://json-schema.org/latest/json-schema-validation.html#anchor14.

This object can be extended with Specification Extensions.

Header Object Example

A simple header with of an integer type:

{
  "description": "The number of allowed requests in the current period",
  "type": "integer"
}
description: The number of allowed requests in the current period
type: integer

Tag Object

Allows adding meta data to a single tag that is used by the Operation Object. It is not mandatory to have a Tag Object per tag used there.

Fixed Fields
Field Name Type Description
name string Required. The name of the tag.
description string A short description for the tag. CommonMark syntax can be used for rich text representation.
externalDocs External Documentation Object Additional external documentation for this tag.

This object can be extended with Specification Extensions.

Tag Object Example
{
	"name": "pet",
	"description": "Pets operations"
}
name: pet
description: Pets operations

Examples Object

Anywhere an example may be given, allow a $ref object. This does mean that example, structurally, can be either a string primitive or an object, like additionalProperties.

In locations where the field being provided an example is a scalar value or has it's content-type definition determined by a higher-level construct (a response payload, for example, uses the produces attribute to select the correct message format), the plural examples shall be used, and the payload format be specified as a key to the example.

In all cases, the payload is expected to be compatible with the type schema for the value that it is accompanying. Tooling Specifications may choose to validate compatibility automatically, and reject the example value(s) if they are not compatible.

# in a model
definitions:
  properties:
    name:
      type: string
      example:
        $ref: http://foo.bar#/examples/name-example

# in a request body, note the plural `examples` as the content-type is set to `*`:
	requestBody:
    content:
      'application/json':
        schema:
          $ref: '#/definitions/Address'
        examples: 
          - {"foo": "bar"}
          - {"bar": "baz"}
      'application/xml':
        examples: 
          -   
            $ref: 'http://foo.bar#/examples/address-example.xml' 
      'text/plain':
        examples: 
          -
            $ref: 'http://foo.bar#/examples/address-example.txt' 
        
# in a parameter

  parameters:
    - name: 'zip'
      in: 'query'
      type: 'string'
      format: 'zip'
      example: 
        $ref: 'http://foo.bar#/examples/zip-example'
# in a response, note the plural `examples`:
  responses:
    200:
      description: your car appointment has been booked
      content: 
        application/json:
          schema:
            $ref: '#/definitions/SuccessResponse'
          example:
            $ref: http://foo.bar#/examples/address-example.json

Reference Object

A simple object to allow referencing other definitions in the specification. It can be used to reference parameters and responses that are defined at the top level for reuse.

The Reference Object is a JSON Reference that uses a JSON Pointer as its value. For this specification, only canonical dereferencing is supported.

Fixed Fields
Field Name Type Description
$ref string Required. The reference string.
Reference Object Example
{
	"$ref": "#/definitions/Pet"
}
$ref: '#/definitions/Pet'
Relative Schema File Example
{
  "$ref": "Pet.json"
}
$ref: 'Pet.yaml'
Relative Files With Embedded Schema Example
{
  "$ref": "definitions.json#/Pet"
}
$ref: 'definitions.yaml#/Pet'

Schema Object

The Schema Object allows the definition of input and output data types. These types can be objects, but also primitives and arrays. This object is based on the JSON Schema Specification Draft 4 and uses a predefined subset of it. On top of this subset, there are extensions provided by this specification to allow for more complete documentation.

Further information about the properties can be found in JSON Schema Core and JSON Schema Validation. Unless stated otherwise, the property definitions follow the JSON Schema specification as referenced here.

The following properties are taken directly from the JSON Schema definition and follow the same specifications:

  • $ref - As a JSON Reference
  • format (See Data Type Formats for further details)
  • title
  • description (CommonMark syntax can be used for rich text representation)
  • default (Unlike JSON Schema, the value MUST conform to the defined type for the Schema Object)
  • multipleOf
  • maximum
  • exclusiveMaximum
  • minimum
  • exclusiveMinimum
  • maxLength
  • minLength
  • pattern
  • maxItems
  • minItems
  • uniqueItems
  • maxProperties
  • minProperties
  • required
  • enum
  • type

The following properties are taken from the JSON Schema definition but their definitions were adjusted to the OpenAPI Specification. Their definition is the same as the one from JSON Schema, only where the original definition references the JSON Schema definition, the Schema Object definition is used instead.

  • items
  • allOf
  • oneOf
  • anyOf
  • not
  • properties
  • additionalProperties

Other than the JSON Schema subset fields, the following fields may be used for further schema documentation.

Fixed Fields
Field Name Type Description
discriminator string Adds support for polymorphism. The discriminator is the schema property name that is used to differentiate between other schema that inherit this schema. The property name used MUST be defined at this schema and it MUST be in the required property list. When used, the value MUST be the name of this schema or any schema that inherits it.
readOnly boolean Relevant only for Schema "properties" definitions. Declares the property as "read only". This means that it MAY be sent as part of a response but MUST NOT be sent as part of the request. Properties marked as readOnly being true SHOULD NOT be in the required list of the defined schema. Default value is false.
xml XML Object This MAY be used only on properties schemas. It has no effect on root schemas. Adds Additional metadata to describe the XML representation format of this property.
externalDocs External Documentation Object Additional external documentation for this schema.
example Any A free-form property to include an example of an instance for this schema.
examples Any An array of free-formed properties to include examples for this schema.
deprecated boolean Specifies that a schema is deprecated and should be transitioned out of usage.

This object can be extended with Specification Extensions.

Composition and Inheritance (Polymorphism)

The OpenAPI Specification allows combining and extending model definitions using the allOf property of JSON Schema, in effect offering model composition. allOf takes in an array of object definitions that are validated independently but together compose a single object.

While composition offers model extensibility, it does not imply a hierarchy between the models. To support polymorphism, OpenAPI Specification adds the support of the discriminator field. When used, the discriminator will be the name of the property used to decide which schema definition is used to validate the structure of the model. As such, the discriminator field MUST be a required field. The value of the chosen property has to be the friendly name given to the model under the definitions property. As such, inline schema definitions, which do not have a given id, cannot be used in polymorphism.

XML Modeling

The xml property allows extra definitions when translating the JSON definition to XML. The XML Object contains additional information about the available options.

Schema Object Examples
Primitive Sample

Unlike previous versions of Swagger, OpenAPI Schema definitions can be used to describe primitive and arrays as well.

{
  "type": "string",
  "format": "email"
}
type: string
format: email
Simple Model
{
  "type": "object",
  "required": [
    "name"
  ],
  "properties": {
    "name": {
      "type": "string"
    },
    "address": {
      "$ref": "#/definitions/Address"
    },
    "age": {
      "type": "integer",
      "format": "int32",
      "minimum": 0
    }
  }
}
type: object
required:
- name
properties:
  name:
    type: string
  address:
    $ref: '#/definitions/Address'
  age:
    type: integer
    format: int32
    minimum: 0
Model with Map/Dictionary Properties

For a simple string to string mapping:

{
  "type": "object",
  "additionalProperties": {
    "type": "string"
  }
}
type: object
additionalProperties:
  type: string

For a string to model mapping:

{
  "type": "object",
  "additionalProperties": {
    "$ref": "#/definitions/ComplexModel"
  }
}
type: object
additionalProperties:
  $ref: '#/definitions/ComplexModel'
Model with Example
{
  "type": "object",
  "properties": {
    "id": {
      "type": "integer",
      "format": "int64"
    },
    "name": {
      "type": "string"
    }
  },
  "required": [
    "name"
  ],
  "example": {
    "name": "Puma",
    "id": 1
  }
}
type: object
properties:
  id:
    type: integer
    format: int64
  name:
    type: string
required:
- name
example:
  name: Puma
  id: 1
Model with Examples
{
  "type": "object",
  "properties": {
    "id": {
      "type": "integer",
      "format": "int64"
    },
    "name": {
      "type": "string"
    }
  },
  "required": [
    "name"
  ],
  "examples": [
  {
    "name": "Puma",
    "id": 1
  }, {
    "name": "Ferguson",
    "id": 2
  }]
}
type: object
properties:
  id:
    type: integer
    format: int64
  name:
    type: string
required:
- name
examples:
  - name: Puma
    id: 1
  - name: Ferguson
    id: 2
Models with Composition
{
  "definitions": {
    "ErrorModel": {
      "type": "object",
      "required": [
        "message",
        "code"
      ],
      "properties": {
        "message": {
          "type": "string"
        },
        "code": {
          "type": "integer",
          "minimum": 100,
          "maximum": 600
        }
      }
    },
    "ExtendedErrorModel": {
      "allOf": [
        {
          "$ref": "#/definitions/ErrorModel"
        },
        {
          "type": "object",
          "required": [
            "rootCause"
          ],
          "properties": {
            "rootCause": {
              "type": "string"
            }
          }
        }
      ]
    }
  }
}
definitions:
  ErrorModel:
    type: object
    required:
    - message
    - code
    properties:
      message:
        type: string
      code:
        type: integer
        minimum: 100
        maximum: 600
  ExtendedErrorModel:
    allOf:
    - $ref: '#/definitions/ErrorModel'
    - type: object
      required:
      - rootCause
      properties:
        rootCause:
          type: string
Models with Polymorphism Support
{
  "definitions": {
    "Pet": {
      "type": "object",
      "discriminator": "petType",
      "properties": {
        "name": {
          "type": "string"
        },
        "petType": {
          "type": "string"
        }
      },
      "required": [
        "name",
        "petType"
      ]
    },
    "Cat": {
      "description": "A representation of a cat",
      "allOf": [
        {
          "$ref": "#/definitions/Pet"
        },
        {
          "type": "object",
          "properties": {
            "huntingSkill": {
              "type": "string",
              "description": "The measured skill for hunting",
              "default": "lazy",
              "enum": [
                "clueless",
                "lazy",
                "adventurous",
                "aggressive"
              ]
            }
          },
          "required": [
            "huntingSkill"
          ]
        }
      ]
    },
    "Dog": {
      "description": "A representation of a dog",
      "allOf": [
        {
          "$ref": "#/definitions/Pet"
        },
        {
          "type": "object",
          "properties": {
            "packSize": {
              "type": "integer",
              "format": "int32",
              "description": "the size of the pack the dog is from",
              "default": 0,
              "minimum": 0
            }
          },
          "required": [
            "packSize"
          ]
        }
      ]
    }
  }
}
definitions:
  Pet:
    type: object
    discriminator: petType
    properties:
      name:
        type: string
      petType:
        type: string
    required:
    - name
    - petType
  Cat:
    description: A representation of a cat
    allOf:
    - $ref: '#/definitions/Pet'
    - type: object
      properties:
        huntingSkill:
          type: string
          description: The measured skill for hunting
          default: lazy
          enum:
          - clueless
          - lazy
          - adventurous
          - aggressive
      required:
      - huntingSkill
  Dog:
    description: A representation of a dog
    allOf:
    - $ref: '#/definitions/Pet'
    - type: object
      properties:
        packSize:
          type: integer
          format: int32
          description: the size of the pack the dog is from
          default: 0
          minimum: 0
      required:
      - packSize

XML Object

A metadata object that allows for more fine-tuned XML model definitions.

When using arrays, XML element names are not inferred (for singular/plural forms) and the name property should be used to add that information. See examples for expected behavior.

Fixed Fields
Field Name Type Description
name string Replaces the name of the element/attribute used for the described schema property. When defined within the Items Object (items), it will affect the name of the individual XML elements within the list. When defined alongside type being array (outside the items), it will affect the wrapping element and only if wrapped is true. If wrapped is false, it will be ignored.
namespace string The URL of the namespace definition. Value SHOULD be in the form of a URL.
prefix string The prefix to be used for the name.
attribute boolean Declares whether the property definition translates to an attribute instead of an element. Default value is false.
wrapped boolean MAY be used only for an array definition. Signifies whether the array is wrapped (for example, <books><book/><book/></books>) or unwrapped (<book/><book/>). Default value is false. The definition takes effect only when defined alongside type being array (outside the items).

This object can be extended with Specification Extensions.

XML Object Examples

The examples of the XML object definitions are included inside a property definition of a Schema Object with a sample of the XML representation of it.

No XML Element

Basic string property:

{
    "animals": {
        "type": "string"
    }
}
animals:
  type: string
<animals>...</animals>

Basic string array property (wrapped is false by default):

{
    "animals": {
        "type": "array",
        "items": {
            "type": "string"
        }
    }
}
animals:
  type: array
  items:
    type: string
<animals>...</animals>
<animals>...</animals>
<animals>...</animals>
XML Name Replacement
{
  "animals": {
    "type": "string",
    "xml": {
      "name": "animal"
    }
  }
}
animals:
  type: string
  xml:
    name: animal
<animal>...</animal>
XML Attribute, Prefix and Namespace

In this example, a full model definition is shown.

{
  "Person": {
    "type": "object",
    "properties": {
      "id": {
        "type": "integer",
        "format": "int32",
        "xml": {
          "attribute": true
        }
      },
      "name": {
        "type": "string",
        "xml": {
          "namespace": "http://swagger.io/schema/sample",
          "prefix": "sample"
        }
      }
    }
  }
}
Person:
  type: object
  properties:
    id:
      type: integer
      format: int32
      xml:
        attribute: true
    name:
      type: string
      xml:
        namespace: http://swagger.io/schema/sample
        prefix: sample
<Person id="123">
    <sample:name xmlns:sample="http://swagger.io/schema/sample">example</sample:name>
</Person>
XML Arrays

Changing the element names:

{
  "animals": {
    "type": "array",
    "items": {
      "type": "string",
      "xml": {
        "name": "animal"
      }
    }
  }
}
animals:
  type: array
  items:
    type: string
    xml:
      name: animal
<animal>value</animal>
<animal>value</animal>

The external name property has no effect on the XML:

{
  "animals": {
    "type": "array",
    "items": {
      "type": "string",
      "xml": {
        "name": "animal"
      }
    },
    "xml": {
      "name": "aliens"
    }
  }
}
animals:
  type: array
  items:
    type: string
    xml:
      name: animal
  xml:
    name: aliens
<animal>value</animal>
<animal>value</animal>

Even when the array is wrapped, if no name is explicitly defined, the same name will be used both internally and externally:

{
  "animals": {
    "type": "array",
    "items": {
      "type": "string"
    },
    "xml": {
      "wrapped": true
    }
  }
}
animals:
  type: array
  items:
    type: string
  xml:
    wrapped: true
<animals>
  <animals>value</animals>
  <animals>value</animals>
</animals>

To overcome the above example, the following definition can be used:

{
  "animals": {
    "type": "array",
    "items": {
      "type": "string",
      "xml": {
        "name": "animal"
      }
    },
    "xml": {
      "wrapped": true
    }
  }
}
animals:
  type: array
  items:
    type: string
    xml:
      name: animal
  xml:
    wrapped: true
<animals>
  <animal>value</animal>
  <animal>value</animal>
</animals>

Affecting both internal and external names:

{
  "animals": {
    "type": "array",
    "items": {
      "type": "string",
      "xml": {
        "name": "animal"
      }
    },
    "xml": {
      "name": "aliens",
      "wrapped": false
    }
  }
}
animals:
  type: array
  items:
    type: string
    xml:
      name: animal
  xml:
    name: aliens
    wrapped: false
<aliens>
  <animal>value</animal>
  <animal>value</animal>
</aliens>

If we change the external element but not the internal ones:

{
  "animals": {
    "type": "array",
    "items": {
      "type": "string"
    },
    "xml": {
      "name": "aliens",
      "wrapped": true
    }
  }
}
animals:
  type: array
  items:
    type: string
  xml:
    name: aliens
    wrapped: true
<aliens>
  <aliens>value</aliens>
  <aliens>value</aliens>
</aliens>

Definitions Object

An object to hold schemas for data types that can be consumed and produced by operations. These data types can be primitives, arrays or models.

Patterned Fields
Field Pattern Type Description
{name} Schema Object A single definition, mapping a "name" to the schema it defines.

Examples:

User
User_1
User_Name
user-name
my.org.User
my\org\User
Definitions Object Example
{
  "Category": {
    "type": "object",
    "properties": {
      "id": {
        "type": "integer",
        "format": "int64"
      },
      "name": {
        "type": "string"
      }
    }
  },
  "Tag": {
    "type": "object",
    "properties": {
      "id": {
        "type": "integer",
        "format": "int64"
      },
      "name": {
        "type": "string"
      }
    }
  }
}
Category:
  type: object
  properties:
    id:
      type: integer
      format: int64
    name:
      type: string
Tag:
  type: object
  properties:
    id:
      type: integer
      format: int64
    name:
      type: string

Parameters Definitions Object

An object to hold parameters to be reused across operations. Parameter definitions can be referenced to the ones defined here.

This does not define global operation parameters.

Patterned Fields
Field Pattern Type Description
{name} Parameter Object A single parameter definition, mapping a "name" to the parameter it defines.
Parameters Definition Object Example
{
  "skipParam": {
    "name": "skip",
    "in": "query",
    "description": "number of items to skip",
    "required": true,
    "type": "integer",
    "format": "int32"
  },
  "limitParam": {
    "name": "limit",
    "in": "query",
    "description": "max records to return",
    "required": true,
    "type": "integer",
    "format": "int32"
  }
}
skipParam:
  name: skip
  in: query
  description: number of items to skip
  required: true
  type: integer
  format: int32
limitParam:
  name: limit
  in: query
  description: max records to return
  required: true
  type: integer
  format: int32

Responses Definitions Object

An object to hold responses to be reused across operations. Response definitions can be referenced to the ones defined here.

This does not define global operation responses.

Patterned Fields
Field Pattern Type Description
{name} Response Object A single response definition, mapping a "name" to the response it defines.
Responses Definitions Object Example
{
  "NotFound": {
    "description": "Entity not found."
  },
  "IllegalInput": {
  	"description": "Illegal input for operation."
  },
  "GeneralError": {
  	"description": "General Error",
  	"schema": {
  		"$ref": "#/definitions/GeneralError"
  	}
  }
}
NotFound:
  description: Entity not found.
IllegalInput:
  description: Illegal input for operation.
GeneralError:
  description: General Error
  schema:
    $ref: '#/definitions/GeneralError'

Security Definitions Object

A declaration of the security schemes available to be used in the specification. This does not enforce the security schemes on the operations and only serves to provide the relevant details for each scheme.

Patterned Fields
Field Pattern Type Description
{name} Security Scheme Object A single security scheme definition, mapping a "name" to the scheme it defines.
Security Definitions Object Example
{
  "api_key": {
    "type": "apiKey",
    "name": "api_key",
    "in": "header"
  },
  "petstore_auth": {
    "type": "oauth2",
    "flow": {
      "implicit": {
        "authorizationUrl": "http://swagger.io/api/oauth/dialog",
        "scopes": {
          "write:pets": "modify pets in your account",
          "read:pets": "read your pets"
        }
      }
    }
  }
}
api_key:
  type: apiKey
  name: api_key
  in: header
petstore_auth:
  type: oauth2
  flow: 
    implicit:
      authorizationUrl: http://swagger.io/api/oauth/dialog
      scopes:
        write:pets: modify pets in your account
        read:pets: read your pets

Security Scheme Object

Allows the definition of a security scheme that can be used by the operations. Supported schemes are HTTP authentication, an API key (either as a header or as a query parameter) and OAuth2's common flows (implicit, password, application and access code).

Fixed Fields
Field Name Type Validity Description
type string Any Required. The type of the security scheme. Valid values are "apiKey", "http", "oauth2", "openIdConnect".
description string Any A short description for security scheme.
name string apiKey Required. The name of the header or query parameter to be used.
in string apiKey Required The location of the API key. Valid values are "query" or "header".
scheme string http Required. The name of the HTTP Authorization scheme to be used in the Authorization header as defined in RFC 7235.
bearerFormat string http ("bearer") A hint to the client to identify how the bearer token is formatted. Bearer tokens are usually generated by an authorization server, so this information is primarily for documentation purposes.
flow OAuth Flows Object oauth2 Required. An object containing configuration information for the flow types supported.
openIdConnectUrl string openIdConnect Required. OpenId Connect URL to discover OAuth2 configuration values. This MUST be in the form of a URL.

This object can be extended with Specification Extensions.

Security Scheme Object Example
Basic Authentication Sample
{
  "type": "http",
  "scheme" : "basic"
}
type: http
scheme: basic
API Key Sample
{
  "type": "apiKey",
  "name": "api_key",
  "in": "header"
}
type: apiKey
name: api_key
in: header
JWT Bearer Sample
{
  "type": "scheme",
  "scheme" : "bearer",
  "bearerFormat" : "JWT",
}
type: http
scheme: bearer
bearerFormat: JWT
Implicit OAuth2 Sample
{
  "type": "oauth2",
  "flow": {
    "implicit": {
      "authorizationUrl": "https://swagger.io/api/oauth/dialog",
      "scopes": {
        "write:pets": "modify pets in your account",
        "read:pets": "read your pets"
      }
    }
  }
}
type: oauth2
flow: 
  implicit:
    authorizationUrl: https://swagger.io/api/oauth/dialog
    scopes:
      write:pets: modify pets in your account
      read:pets: read your pets

OAuth Flows Object

Allows configuration of the supported OAuth Flows.

Fixed Fields

Field Name | Type | Description ---|:---:|---|--- implicit| OAuth Flow Object | Configuration for the OAuth Implicit flow password| OAuth Flow Object | Configuration for the OAuth Resource Owner Password flow clientCredentials| OAuth Flow Object | Configuration for the OAuth Client Credentials flow. Previously called application in OpenApi 2.0. authorizationCode| OAuth Flow Object | Configuration for the OAuth Authorization Code flow. Previously called accessCode in OpenApi 2.0.

This object can be extended with Specification Extensions.

OAuth Flow Object

Configuration details for a supported OAuth Flow

Fixed Fields
Field Name Type Validity Description
authorizationUrl string oauth2 ("implicit", "authorizationCode") Required. The authorization URL to be used for this flow. This MUST be in the form of a URL.
tokenUrl string oauth2 ("password", "clientCredentials", "authorizationCode") Required. The token URL to be used for this flow. This MUST be in the form of a URL.
refreshUrl string oauth2 The URL to be used for obtaining refresh tokens. This MUST be in the form of a URL.
scopes Scopes Object oauth2 Required. The available scopes for the OAuth2 security scheme.

This object can be extended with Specification Extensions.

OAuth Flow Object Examples
{
  "type": "oauth2",
  "flow": {
    "implicit": {
      "authorizationUrl": "https://swagger.io/api/oauth/dialog",
      "scopes": {
        "write:pets": "modify pets in your account",
        "read:pets": "read your pets"
      }
    },
    "authorizationCode": {
      "authorizationUrl": "https://swagger.io/api/oauth/dialog",
      "tokenUrl": "https://swagger.io/api/oauth/token",
      "scopes": {
        "write:pets": "modify pets in your account",
        "read:pets": "read your pets"
      }
    }
  }
}
type: oauth2
flow: 
  implicit:
    authorizationUrl: https://swagger.io/api/oauth/dialog
    scopes:
      write:pets: modify pets in your account
      read:pets: read your pets
  authorizationCode:
    authorizationUrl: https://swagger.io/api/oauth/dialog
    tokenUrl: https://swagger.io/api/oauth/token
    scopes:
      write:pets: modify pets in your account
      read:pets: read your pets

Scopes Object

Lists the available scopes for an OAuth2 security scheme.

Patterned Fields
Field Pattern Type Description
{name} string Maps between a name of a scope to a short description of it (as the value of the property).

This object can be extended with Specification Extensions.

Scopes Object Example
{
  "write:pets": "modify pets in your account",
  "read:pets": "read your pets"
}
write:pets: modify pets in your account
read:pets: read your pets

Security Requirement Object

Lists the required security schemes to execute this operation. The name used for each property MUST correspond to a security scheme declared in the Security Definitions.

Security Requirement Objects that contain multiple schemes require that all schemes MUST be satisfied for a request to be authorized. This enables support for scenarios where there multiple query parameters or HTTP headers are required to convey security information.

When a list of Security Requirement Objects is defined on the Open API object or Operation Object, only one of Security Requirement Objects in the list needs to be satisfied to authorize.

Patterned Fields
Field Pattern Type Description
{name} [string] Each name must correspond to a security scheme which is declared in the Security Definitions. If the security scheme is of type "oauth2" or "openIdConnect", then the value is a list of scope names required for the execution. For other security scheme types, the array MUST be empty.
Security Requirement Object Examples
Non-OAuth2 Security Requirement
{
  "api_key": []
}
api_key: []
OAuth2 Security Requirement
{
  "petstore_auth": [
    "write:pets",
    "read:pets"
  ]
}
petstore_auth:
- write:pets
- read:pets

Specification Extensions

While the OpenAPI Specification tries to accommodate most use cases, additional data can be added to extend the specification at certain points.

The extensions properties are implemented as patterned fields that are always prefixed by "x-".

Field Pattern Type Description
^x- Any Allows extensions to the OpenAPI Schema. The field name MUST begin with x-, for example, x-internal-id. The value can be null, a primitive, an array or an object. Can have any valid JSON format value.

The extensions may or may not be supported by the available tooling, but those may be extended as well to add requested support (if tools are internal or open-sourced).

Security Filtering

Some objects in the OpenAPI Specification may be declared and remain empty, or completely be removed, even though they are inherently the core of the API documentation.

The reasoning behind it is to allow an additional layer of access control over the documentation itself. While not part of the specification itself, certain libraries may choose to allow access to parts of the documentation based on some form of authentication/authorization.

Two examples for this:

  1. The Paths Object may be empty. It may be counterintuitive, but this may tell the viewer that they got to the right place, but can't access any documentation. They'd still have access to the Info Object which may contain additional information regarding authentication.
  2. The Path Item Object may be empty. In this case, the viewer will be aware that the path exists, but will not be able to see any of its operations or parameters. This is different than hiding the path itself from the Paths Object so the user will not be aware of its existence. This allows the documentation provider a finer control over what the viewer can see.