The Arazzo Specification provides a mechanism that can define sequences of calls and their dependencies to be woven together and expressed in the context of delivering a particular outcome or set of outcomes when dealing with API descriptions (such as OpenAPI descriptions).

Specification

Versions

The Arazzo Specification is versioned using a major.minor.patch versioning scheme. The major.minor portion of the version string (for example 1.0) SHALL designate the Arazzo feature set. .patch versions address errors in, or provide clarifications to, this document, not the feature set. The patch version SHOULD NOT be considered by tooling, making no distinction between 1.0.0 and 1.0.1 for example.

Format

An Arazzo Description that conforms to the Arazzo Specification is itself a JSON object, which may be represented either in JSON or YAML format.

All field names in the specification are case sensitive. This includes all fields that are used as keys in a map, except where explicitly noted that keys are case insensitive.

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.

Arazzo Description Structure

It is RECOMMENDED that the entry Arazzo document be named: arazzo.json or arazzo.yaml.

An Arazzo Description MAY be made up of a single document or be divided into multiple, connected parts at the discretion of the author. If workflows from other documents are being referenced, they must by included as a Source Description Object. In a multi-document description, the document containing the Arazzo Specification Object is known as the entry Arazzo document.

Data Types

Data types in the Arazzo Specification are based on the types supported by the JSON Schema Specification Draft 2020-12. Note that integer as a type is also supported and is defined as a JSON number without a fraction or exponent part.

As defined by the JSON Schema Validation vocabulary, data types can have an optional modifier property: format. Arazzo additionally supports the formats (similar to the OpenAPI specification) to provide fine detail for primitive data types.

The formats defined are:

`type`	`format`	Comments
`integer`	`int32`	signed 32 bits
`integer`	`int64`	signed 64 bits (a.k.a long)
`number`	`float`
`number`	`double`
`string`	`password`	A hint to UIs to obscure input.

Relative References in URLs

Unless specified otherwise, all properties that are URLs MAY be relative references as defined by [[!RFC3986]] Section 4.2. Unless specified otherwise, relative references are resolved using the URL of the referring document.

Schema

In the following description, if a field is not explicitly REQUIRED or described with a MUST or SHALL, it can be considered OPTIONAL.

Arazzo Specification Object

This is the root object of the Arazzo Description.

Fixed Fields

Field Name	Type	Description
arazzo	`string`	REQUIRED. This string MUST be the version number of the Arazzo Specification that the Arazzo Description uses. The `arazzo` field MUST be used by tooling to interpret the Arazzo Description.
info	Info Object	REQUIRED. Provides metadata about the workflows contain within the Arazzo Description. The metadata MAY be used by tooling as required.
sourceDescriptions	[Source Description Object]	REQUIRED. A list of source descriptions (such as an OpenAPI description) this Arazzo Description SHALL apply to. The list MUST have at least one entry.
workflows	[Workflow Object]	REQUIRED. A list of workflows. The list MUST have at least one entry.
components	Components Object	An element to hold various schemas for the Arazzo Description.

This object MAY be extended with Specification Extensions.

Arazzo Specification Object Example


arazzo: 1.0.0
info:
  title: A pet purchasing workflow
  summary: This Arazzo Description showcases the workflow for how to purchase a pet through a sequence of API calls
  description: |
      This Arazzo Description walks you through the workflow and steps of `searching` for, `selecting`, and `purchasing` an available pet.
  version: 1.0.1
sourceDescriptions:
- name: petStoreDescription
  url: https://github.com/swagger-api/swagger-petstore/blob/master/src/main/resources/openapi.yaml
  type: openapi

workflows:
- workflowId: loginUserAndRetrievePet
  summary: Login User and then retrieve pets
  description: This workflow lays out the steps to login a user and then retrieve pets
  inputs:
      type: object
      properties:
          username:
              type: string
          password:
              type: string
  steps:
  - stepId: loginStep
    description: This step demonstrates the user login step
    operationId: loginUser
    parameters:
      # parameters to inject into the loginUser operation (parameter name must be resolvable at the referenced operation and the value is determined using {expression} syntax)
      - name: username
        in: query
        value: $inputs.username
      - name: password
        in: query
        value: $inputs.password
    successCriteria:
      # assertions to determine step was successful
      - condition: $statusCode == 200
    outputs:
      # outputs from this step
      tokenExpires: $response.header.X-Expires-After
      rateLimit: $response.header.X-Rate-Limit
      sessionToken: $response.body
  - stepId: getPetStep
    description: retrieve a pet by status from the GET pets endpoint
    operationPath: '{$sourceDescriptions.petstoreDescription.url}#/paths/~1pet~1findByStatus/get'
    parameters:
      - name: status
        in: query
        value: 'available'
      - name: Authorization
        in: header
        value: $steps.loginUser.outputs.sessionToken
    successCriteria:
      - condition: $statusCode == 200
    outputs:
      # outputs from this step
      availablePets: $response.body
  outputs:
      available: $steps.getPetStep.availablePets

Info Object

The object provides metadata about API workflows defined in this Arazzo document. The metadata MAY be used by the clients if needed.

Fixed Fields

Field Name	Type	Description
title	`string`	REQUIRED. A human readable title of the Arazzo Description.
summary	`string`	A short summary of the Arazzo Description.
description	`string`	A description of the purpose of the workflows defined. CommonMark syntax MAY be used for rich text representation.
version	`string`	REQUIRED. The version identifier of the Arazzo document (which is distinct from the Arazzo Specification version).

This object MAY be extended with Specification Extensions.

Info Object Example


title: A pet purchasing workflow
summary: This workflow showcases how to purchase a pet through a sequence of API calls
description: |
    This workflow walks you through the steps of searching for, selecting, and purchasing an available pet.
version: 1.0.1

Source Description Object

Describes a source description (such as an OpenAPI description) that will be referenced by one or more workflows described within an Arazzo Description.

An object storing a map between named description keys and location URLs to the source descriptions (such as an OpenAPI description) this Arazzo Description SHALL apply to. Each source location string MUST be in the form of a URI-reference as defined by [[!RFC3986]] Section 4.1.

Fixed Fields

Field Name	Type	Description
name	`string`	REQUIRED. A unique name for the source description. Tools and libraries MAY use the `name` to uniquely identify a source description, therefore, it is RECOMMENDED to follow common programming naming conventions. SHOULD conform to the regular expression `[A-Za-z0-9_\-]+`.
url	`string`	REQUIRED. A URL to a source description to be used by a workflow. If a relative reference is used, it MUST be in the form of a URI-reference as defined by [[!RFC3986]] Section 4.2.
type	`string`	The type of source description. Possible values are `"openapi"` or `"arazzo"`.

This object MAY be extended with Specification Extensions.

Source Description Object Example


name: petStoreDescription
url: https://github.com/swagger-api/swagger-petstore/blob/master/src/main/resources/openapi.yaml
type: openapi

Workflow Object

Describes the steps to be taken across one or more APIs to achieve an objective. The workflow object MAY define inputs needed in order to execute workflow steps, where the defined steps represent a call to an API operation or another workflow, and a set of outputs.

Fixed Fields

Field Name	Type	Description
workflowId	`string`	REQUIRED. Unique string to represent the workflow. The id MUST be unique amongst all workflows describe in the Arazzo Description. The `workflowId` value is case-sensitive. Tools and libraries MAY use the `workflowId` to uniquely identify a workflow, therefore, it is RECOMMENDED to follow common programming naming conventions. SHOULD conform to the regular expression `[A-Za-z0-9_\-]+`.
summary	`string`	A summary of the purpose or objective of the workflow.
description	`string`	A description of the workflow. CommonMark syntax MAY be used for rich text representation.
inputs	`JSON Schema`	A JSON Schema 2020-12 object representing the input parameters used by this workflow.
dependsOn	[`string`]	A list of workflows that MUST be completed before this workflow can be processed. The values provided MUST be a `workflowId`. If the workflow depended on is defined within the current Workflow Document, then specify the `workflowId` of the relevant local workflow. If the workflow is defined in a separate Arazzo Document then the workflow MUST be defined in the `sourceDescriptions` and the `workflowId` MUST be specified using a runtime expression (e.g., `$sourceDescriptions.<name>.<workflowId>`) to avoid ambiguity or potential clashes.
steps	[Step Object]	REQUIRED. An ordered list of steps where each step represents a call to an API operation or to another workflow.
successActions	[Success Action Object \| Reusable Object]	A list of success actions that are applicable for all steps described under this workflow. These success actions can be overridden at the step level but cannot be removed there. If a Reusable Object is provided, it MUST link to success actions defined in the components/successActions of the current Arazzo document. The list MUST NOT include duplicate success actions.
failureActions	[Failure Action Object \| Reusable Object]	A list of failure actions that are applicable for all steps described under this workflow. These failure actions can be overridden at the step level but cannot be removed there. If a Reusable Object is provided, it MUST link to failure actions defined in the components/failureActions of the current Arazzo document. The list MUST NOT include duplicate failure actions.
outputs	Map[`string`, {expression}]	A map between a friendly name and a dynamic output value. The name MUST use keys that match the regular expression: `^[a-zA-Z0-9\.\-_]+$`.
parameters	[Parameter Object \| Reusable Object]	A list of parameters that are applicable for all steps described under this workflow. These parameters can be overridden at the step level but cannot be removed there. Each parameter MUST be passed to an operation or workflow as referenced by `operationId`, `operationPath`, or `workflowId` as specified within each step. If a Reusable Object is provided, it MUST link to a parameter defined in the components/parameters of the current Arazzo document. The list MUST NOT include duplicate parameters.

This object MAY be extended with Specification Extensions.

Workflow Object Example


workflowId: loginUser
summary: Login User
description: This workflow lays out the steps to login a user
inputs:
    type: object
    properties:
        username:
            type: string
        password:
            type: string
steps:
  - stepId: loginStep
    description: This step demonstrates the user login step
    operationId: loginUser
    parameters:
      # parameters to inject into the loginUser operation (parameter name must be resolvable at the referenced operation and the value is determined using {expression} syntax)
      - name: username
        in: query
        value: $inputs.username
      - name: password
        in: query
        value: $inputs.password
    successCriteria:
        # assertions to determine step was successful 
        - condition: $statusCode == 200
    outputs:
        # outputs from this step
        tokenExpires: $response.header.X-Expires-After
        rateLimit: $response.header.X-Rate-Limit
outputs:
    tokenExpires: $steps.loginStep.outputs.tokenExpires

Step Object

Describes a single workflow step which MAY be a call to an API operation (OpenAPI Operation Object or another Workflow Object).

Fixed Fields

Field Name	Type	Description
description	`string`	A description of the step. CommonMark syntax MAY be used for rich text representation.
stepId	`string`	REQUIRED. Unique string to represent the step. The `stepId` MUST be unique amongst all steps described in the workflow. The `stepId` value is case-sensitive. Tools and libraries MAY use the `stepId` to uniquely identify a workflow step, therefore, it is RECOMMENDED to follow common programming naming conventions. SHOULD conform to the regular expression `[A-Za-z0-9_\-]+`.
operationId	`string`	The name of an existing, resolvable operation, as defined with a unique `operationId` and existing within one of the `sourceDescriptions`. The referenced operation will be invoked by this workflow step. If multiple (non `arazzo` type) `sourceDescriptions` are defined, then the `operationId` MUST be specified using a runtime expression (e.g., `$sourceDescriptions.<name>.<operationId>`) to avoid ambiguity or potential clashes. This field is mutually exclusive of the `operationPath` and `workflowId` fields respectively.
operationPath	`string`	A reference to a Source combined with a JSON Pointer to reference an operation. This field is mutually exclusive of the `operationId` and `workflowId` fields respectively. The operation being referenced MUST be described within one of the `sourceDescriptions` descriptions. A runtime expression syntax MUST be used to identify the source description document. If the referenced operation has an `operationId` defined then the `operationId` SHOULD be preferred over the `operationPath`.
workflowId	`string`	The workflowId referencing an existing workflow within the Arazzo Description. If multiple `arazzo` type `sourceDescriptions` are defined, then the `workflowId` MUST be specified using a runtime expression (e.g., `$sourceDescriptions.<name>.<workflowId>`) to avoid ambiguity or potential clashes. The field is mutually exclusive of the `operationId` and `operationPath` fields respectively.
parameters	[Parameter Object \| Reusable Object]	A list of parameters that MUST be passed to an operation or workflow as referenced by `operationId`, `operationPath`, or `workflowId`. If a parameter is already defined at the Workflow, the new definition will override it but can never remove it. If a Reusable Object is provided, it MUST link to a parameter defined in the components/parameters of the current Arazzo document. The list MUST NOT include duplicate parameters.
requestBody	Request Body Object	The request body to pass to an operation as referenced by `operationId` or `operationPath`. The `requestBody` is fully supported in HTTP methods where the HTTP 1.1 specification [[!RFC7231]] Section 4.3.1 has explicitly defined semantics for request bodies. In other cases where the HTTP spec is vague (such as GET, HEAD and DELETE), `requestBody` is permitted but does not have well-defined semantics and SHOULD be avoided if possible.
successCriteria	[Criterion Object]	A list of assertions to determine the success of the step. Each assertion is described using a Criterion Object. All assertions `MUST` be satisfied for the step to be deemed successful.
onSuccess	[Success Action Object \| Reusable Object]	An array of success action objects that specify what to do upon step success. If omitted, the next sequential step shall be executed as the default behavior. If multiple success actions have similar `criteria`, the first sequential action matching the criteria SHALL be the action executed. If a success action is already defined at the Workflow, the new definition will override it but can never remove it. If a Reusable Object is provided, it MUST link to a success action defined in the components of the current Arazzo document. The list MUST NOT include duplicate success actions.
onFailure	[Failure Action Object \| Reusable Object]	An array of failure action objects that specify what to do upon step failure. If omitted, the default behavior is to break and return. If multiple failure actions have similar `criteria`, the first sequential action matching the criteria SHALL be the action executed. If a failure action is already defined at the Workflow, the new definition will override it but can never remove it. If a Reusable Object is provided, it MUST link to a failure action defined in the components of the current Arazzo document. The list MUST NOT include duplicate failure actions.
outputs	Map[`string`, {expression}]	A map between a friendly name and a dynamic output value defined using a runtime expression. The name MUST use keys that match the regular expression: `^[a-zA-Z0-9\.\-_]+$`.

This object MAY be extended with Specification Extensions.

Step Object Example

Single step


stepId: loginStep
description: This step demonstrates the user login step
operationId: loginUser
parameters:
    # parameters to inject into the loginUser operation (parameter name must be resolvable at the referenced operation and the value is determined using {expression} syntax)
    - name: username
      in: query
      value: $inputs.username
    - name: password
      in: query
      value: $inputs.password
successCriteria:
    # assertions to determine step was successful
    - condition: $statusCode == 200
outputs:
    # outputs from this step
    tokenExpires: $response.header.X-Expires-After
    rateLimit: $response.header.X-Rate-Limit

Multiple steps


steps:
  - stepId: loginStep
    description: This step demonstrates the user login step
    operationId: loginUser
    parameters:
        # parameters to inject into the loginUser operation (parameter name must be resolvable at the referenced operation and the value is determined using {expression} syntax)
      - name: username
        in: query
        value: $inputs.username
      - name: password
        in: query
        value: $inputs.password
    successCriteria:
        # assertions to determine step was successful
      - condition: $statusCode == 200
    outputs:
        # outputs from this step
        tokenExpires: $response.header.X-Expires-After
        rateLimit: $response.header.X-Rate-Limit
        sessionToken: $response.body
  - stepId: getPetStep
    description: retrieve a pet by status from the GET pets endpoint
    operationPath: '{$sourceDescriptions.petStoreDescription.url}#/paths/~1pet~1findByStatus/get'
    parameters:
      - name: status
        in: query
        value: 'available'
      - name: Authorization
        in: header
        value: $steps.loginUser.outputs.sessionToken
    successCriteria:
      - condition: $statusCode == 200
    outputs:
        # outputs from this step
        availablePets: $response.body

Parameter Object

Describes a single step parameter. A unique parameter is defined by the combination of a name and in fields. There are four possible locations specified by the in field:

path - Used together with OpenAPI style 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. Note that [[!RFC7230]] Page 22 states header names are case insensitive.
cookie - Used to pass a specific cookie value to the source API.

Fixed Fields

Field Name	Type	Description
name	`string`	REQUIRED. The name of the parameter. Parameter names are case sensitive.
in	`string`	The name location of the parameter. Possible values are `"path"`, `"query"`, `"header"`, `"cookie"`, or `"body"`. When the step in context specifies a `workflowId`, then all parameters map to workflow inputs. In all other scenarios (e.g., a step specifies an `operationId`), the `in` field MUST be specified.
value	Any \| {expression}	REQUIRED. The value to pass in the parameter. The value can be a constant or an Runtime Expression to be evaluated and passed to the referenced operation or workflow.

This object MAY be extended with Specification Extensions.

Parameter Object Example

Query Example


- name: username
  in: query
  value: $inputs.username

Header Example


- name: X-Api-Key
  in: header
  value: $inputs.x-api-key

Success Action Object

A single success action which describes an action to take upon success of a workflow step. There are two possible values for the type field.

end - The workflow ends, and context returns to the caller with applicable outputs
goto - A one-way transfer of workflow control to the specified label (either a workflowId or stepId)

Fixed Fields

Field Name	Type	Description
name	`string`	REQUIRED. The name of the success action. Names are case sensitive.
type	`string`	REQUIRED. The type of action to take. Possible values are `"end"` or `"goto"`.
workflowId	`string`	The workflowId referencing an existing workflow within the Arazzo Description to transfer to upon success of the step. This field is only relevant when the `type` field value is `"goto"`. If multiple `arazzo` type `sourceDescriptions` are defined, then the `workflowId` MUST be specified using a runtime expression (e.g., `$sourceDescriptions.<name>.<workflowId>`) to avoid ambiguity or potential clashes. This field is mutually exclusive to `stepId`.
stepId	`string`	The `stepId` to transfer to upon success of the step. This field is only relevant when the `type` field value is `"goto"`. The referenced `stepId` MUST be within the current workflow. This field is mutually exclusive to `workflowId`.
criteria	[Criterion Object]	A list of assertions to determine if this action SHALL be executed. Each assertion is described using a Criterion Object. All criteria assertions `MUST` be satisfied for the action to be executed.

This object MAY be extended with Specification Extensions.

Success Action Object Example


name: JoinWaitingList
type: goto
stepId: joinWaitingListStep
criteria:
    # assertions to determine if this success action should be executed
    - context: $response.body
      condition: $[?count(@.pets) > 0]
      type: jsonpath

Failure Action Object

A single failure action which describes an action to take upon failure of a workflow step. There are three possible values for the type field.

end - The workflow ends, and context returns to the caller with applicable outputs
retry - The current step will be retried. The retry will be constrained by the retryAfter and retryLimit fields. If a stepId or workflowId are specified, then the reference is executed and the context is returned, after which the current step is retried.
goto - A one-way transfer of workflow control to the specified label (either a workflowId or stepId)

Fixed Fields

Field Name	Type	Description
name	`string`	REQUIRED. The name of the failure action. Names are case sensitive.
type	`string`	REQUIRED. The type of action to take. Possible values are `"end"`, `"retry"`, or `"goto"`.
workflowId	`string`	The workflowId referencing an existing workflow within the Arazzo Description to transfer to upon failure of the step. This field is only relevant when the `type` field value is `"goto"` or `"retry"`. If multiple `arazzo` type `sourceDescriptions` are defined, then the `workflowId` MUST be specified using a runtime expression (e.g., `$sourceDescriptions.<name>.<workflowId>`) to avoid ambiguity or potential clashes. This field is mutually exclusive to `stepId`. When used with `"retry"`, context transfers back upon completion of the specified workflow.
stepId	`string`	The `stepId` to transfer to upon failure of the step. This field is only relevant when the `type` field value is `"goto"` or `"retry"`. The referenced `stepId` MUST be within the current workflow. This field is mutually exclusive to `workflowId`. When used with `"retry"`, context transfers back upon completion of the specified step.
retryAfter	`number`	A non-negative decimal indicating the seconds to delay after the step failure before another attempt SHALL be made. Note: if an HTTP Retry-After response header was returned to a step from a targeted operation, then it SHOULD overrule this particular field value. This field only applies when the `type` field value is `"retry"` or `"function"`.
retryLimit	`integer`	A non-negative integer indicating how many attempts to retry the step MAY be attempted before failing the overall step. If not specified then a single retry SHALL be attempted. This field only applies when the `type` field value is `"retry"`. The `retryLimit` MUST be exhausted prior to executing subsequent failure actions.
criteria	[Criterion Object]	A list of assertions to determine if this action SHALL be executed. Each assertion is described using a Criterion Object.

This object MAY be extended with Specification Extensions.

Failure Action Object Example


name: retryStep
type: retry
retryAfter: 1
retryLimit: 5
criteria:
    # assertions to determine if this action should be executed
    - condition: $statusCode == 503

Components Object

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

Components are scoped to the Arazzo document they are defined in. For example, if a step defined in Arazzo document “A” references a workflow defined in Arazzo document “B”, the components in “A” are not considered when evaluating the workflow referenced in “B”.

Fixed Fields

Field Name	Type	Description
inputs	Map[`string`, `JSON Schema`]	An object to hold reusable JSON Schema objects to be referenced from workflow inputs.
parameters	Map[`string`, Parameter Object]	An object to hold reusable Parameter Objects
successActions	Map[`string`, Success Action Object]	An object to hold reusable Success Actions Objects.
failureActions	Map[`string`, Failure Action Object]	An object to hold reusable Failure Actions Objects.

This object MAY be extended with Specification Extensions.

All the fixed fields declared above are objects that MUST use keys that match the regular expression: ^[a-zA-Z0-9\.\-_]+$. The key is used to refer to the input or parameter in other parts of the Workflow Description.

Field Name Examples:


User
User_1
User_Name
user-name
my.org.User

Components Object Example


components:
  parameters:
    storeId:
      name: storeId
      in: header
      value: $inputs.x-store-id
  inputs:
    pagination:
      type: object
      properties:
        page:
          type: integer
          format: int32
        pageSize:
          type: integer
          format: int32
  failureActions:
    refreshToken:
      name: refreshExpiredToken
      type: retry
      retryAfter: 1
      retryLimit: 5
      workflowId: refreshTokenWorkflowId
      criteria:
          # assertions to determine if this action should be executed
          - condition: $statusCode == 401


"components": {
  "parameters": {
    "storeId": {
      "name": "storeId",
      "in": "header",
      "value": "$inputs.x-store-id"
    }
  },
  "inputs": {
    "pagination": {
      "type": "object",
      "properties": {
        "page": {
          "type": "integer",
          "format": "int32"
        },
        "pageSize": {
          "type": "integer",
          "format": "int32"
        }
      }
    }
  },
  "failureActions": {
    "refreshToken": {
      "name": "refreshExpiredToken",
      "type": "retry",
      "retryAfter": 1,
      "retryLimit": 5,
      "workflowId": "refreshTokenWorkflowId",
      "criteria": [
        {
          "condition": "{$statusCode == 401}"
        }
      ]
    }
  }
}

Reusable Object

A simple object to allow referencing of objects contained within the Components Object. It can be used from locations within steps or workflows in the Arazzo Description. Note - Input Objects MUST use standard JSON Schema referencing via the $ref keyword while all non JSON Schema objects use this object and its expression based referencing mechanism.

Fixed Fields

Field Name	Type	Description
reference	`{expression}`	REQUIRED. A runtime expression used to reference the desired object.
value	`string`	Sets a value of the referenced parameter. This is only applicable for parameter object references.

This object cannot be extended with additional properties and any properties added MUST be ignored.

Reusable Object Example


  reference: $components.successActions.notify


  {
    "reference": "$components.successActions.notify"
  }


  reference: $components.parameters.page
  value: 1


  {
    "reference": "$components.parameters.page",
    "value": 1
  }

Criterion Object

An object used to specify the context, conditions, and condition types that can be used to prove or satisfy assertions specified in Step Object successCriteria, Success Action Object criteria, and Failure Action Object criteria.

There are four flavors of conditions supported:

simple - where basic literals, operators, and loose comparisons are used in combination with Runtime Expressions.
regex - where a regex pattern is applied on the supplied context. The context is defined by a Runtime Expression.
jsonpath - where a JSONPath expression is applied. The root node context is defined by a Runtime Expression.
xpath - where an XPath expression is applied. The root node context is defined by a Runtime Expression.

Literals

As part of a condition expression, you can use boolean, null, number, or string data types.

Type	Literal value
`boolean`	`true` or `false`
`null`	`null`
`number`	Any number format supported in Data Types
`string`	Strings MUST use single quotes (‘) around the string. To use a literal single quote, escape the literal single quote using an additional single quote (’').

Operators

Operator	Description
`<`	Less than
`<=`	Less than or equal
`>`	Greater than
`>=`	Greater than or equal
`==`	Equal
`!=`	Not equal
`!`	Not
`&&`	And
`\|\|`	Or
`()`	Logical Grouping
`[]`	Index (0-based)
`.`	Property de-reference

String comparisons MUST be case insensitive.

Fixed Fields

Field Name	Type	Description
context	`{expression}`	A runtime expression used to set the context for the condition to be applied on. If `type` is specified, then the `context` MUST be provided (e.g. `$response.body` would set the context that a JSONPath query expression could be applied to).
condition	`string`	REQUIRED. The condition to apply. Conditions can be simple (e.g. `$statusCode == 200` which applies an operator on a value obtained from a runtime expression), or a regex, or a JSONPath expression. For regex or JSONPath, the `type` and `context` MUST be specified.
type	`string` \| Criterion Expression Type Object	The type of condition to be applied. If specified, the options allowed are `simple`, `regex`, `jsonpath` or `xpath`. If omitted, then the condition is assumed to be `simple`, which at most combines literals, operators and Runtime Expressions. If `jsonpath`, then the expression MUST conform to JSONPath. If `xpath` the expression MUST conform to XML Path Language 3.1. Should other variants of JSONPath or XPath be required, then a Criterion Expression Type Object MUST be specified.

This object MAY be extended with Specification Extensions.

Criterion Object Example

Simple Condition Example


- condition: $statusCode == 200

Regex Condition Example


- context: $statusCode
  condition: '^200$'
  type: regex

JSONPath Condition Example


- context: $response.body
  condition: $[?count(@.pets) > 0]
  type: jsonpath

Criterion Expression Type Object

An object used to describe the type and version of an expression used within a Criterion Object. If this object is not defined, then the following defaults apply:

JSONPath as described by [[!RFC9535]]
XPath as described by XML Path Language 3.1

Defining this object gives the ability to utilize tooling compatible with older versions of either JSONPath or XPath.

Fixed Fields

Field Name	Type	Description
type	`string`	REQUIRED. The type of condition to be applied. The options allowed are `jsonpath` or `xpath`.
version	`string`	REQUIRED. A short hand string representing the version of the expression type being used. The allowed values for JSONPath are `draft-goessner-dispatch-jsonpath-00`. The allowed values for XPath are `xpath-30`, `xpath-20`, or `xpath-10`.

This object MAY be extended with Specification Extensions.

Criterion Expression Type Example

JSONPath Example


  type: jsonpath
  version: draft-goessner-dispatch-jsonpath-00

XPath Example


  type: xpath
  version: xpath-30

Request Body Object

A single request body describing the Content-Type and request body content to be passed by a step to an operation.

Fixed Fields

Field Name	Type	Description
contentType	`string`	The Content-Type for the request content. If omitted then refer to Content-Type specified at the targeted operation to understand serialization requirements.
payload	Any	A value representing the request body payload. The value can be a literal value or can contain Runtime Expressions which MUST be evaluated prior to calling the referenced operation. To represent examples of media types that cannot be naturally represented in JSON or YAML, use a string value to contain the example, escaping where necessary.
replacements	[Payload Replacement Object]	A list of locations and values to set within a payload.

This object MAY be extended with Specification Extensions.

RequestBody Object Example

JSON Templated Example


  contentType: application/json
  payload: |
    {
      "petOrder": {
        "petId": "{$inputs.pet_id}",
        "couponCode": "{$inputs.coupon_code}",
        "quantity": "{$inputs.quantity}",
        "status": "placed",
        "complete": false
      }
    }

JSON Object Example


  contentType: application/json
  payload: 
    petOrder:
      petId: $inputs.pet_id
      couponCode: $inputs.coupon_code
      quantity: $inputs.quantity
      status: placed
      complete: false

Complete Runtime Expression


  contentType: application/json
  payload: $inputs.petOrderRequest

XML Templated Example


  contentType: application/xml
  payload: |
    <petOrder>
      <petId>{$inputs.pet_id}</petId>
      <couponCode>{$inputs.coupon_code}</couponCode>
      <quantity>{$inputs.quantity}</quantity>
      <status>placed</status>
      <complete>false</complete>
    </petOrder>

Form Data Example


  contentType: application/x-www-form-urlencoded
  payload: 
    client_id: $inputs.clientId
    grant_type: $inputs.grantType
    redirect_uri: $inputs.redirectUri
    client_secret: $inputs.clientSecret
    code: $steps.browser-authorize.outputs.code
    scope: $inputs.scope

Form Data String Example


  contentType: application/x-www-form-urlencoded
  payload: "client_id={$inputs.clientId}&grant_type={$inputs.grantType}&redirect_uri={$inputs.redirectUri}&client_secret={$inputs.clientSecret}&code{$steps.browser-authorize.outputs.code}&scope=$inputs.scope}"

Payload Replacement Object

Describes a location within a payload (e.g., a request body) and a value to set within the location.

Fixed Fields

Field Name	Type	Description
target	`string`	REQUIRED. A JSON Pointer or XPath Expression which MUST be resolved against the request body. Used to identify the location to inject the `value`.
value	Any \| {expression}	REQUIRED. The value set within the target location. The value can be a constant or a Runtime Expression to be evaluated and passed to the referenced operation or workflow.

This object MAY be extended with Specification Extensions.

Payload Replacement Object Example

Runtime Expression Example


  target: /petId
  value: $inputs.pet_id

Literal Example


  target: /quantity
  value: 10

Runtime Expressions

A runtime expression allows values to be defined based on information that will be available within an HTTP message, an event message, and within objects serialized from the Arazzo document such as workflows or steps.

The runtime expression is defined by the following ABNF syntax:


      expression = ( "$url" / "$method" / "$statusCode" / "$request." source / "$response." source / "$message." source / "$inputs." name / "$outputs." name / "$steps." name / "$workflows." name / "$sourceDescriptions." name / "$components." name / "$components.parameters." parameter-name)
      parameter-name = name ; Reuses 'name' rule for parameter names
      source = ( header-reference / query-reference / path-reference / body-reference )
      header-reference = "header." token
      query-reference = "query." name
      path-reference = "path." name
      body-reference = "body" ["#" json-pointer ]
      json-pointer    = *( "/" reference-token )
      reference-token = *( unescaped / escaped )
      unescaped       = %x00-2E / %x30-7D / %x7F-10FFFF
         ; %x2F ('/') and %x7E ('~') are excluded from 'unescaped'
      escaped         = "~" ( "0" / "1" )
        ; representing '~' and '/', respectively
      name = *( CHAR )
      token = 1*tchar
      tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." /
        "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA

Examples

Source Location	example expression	notes
HTTP Method	`$method`	The allowable values for the `$method` will be those for the HTTP operation.
Requested media type	`$request.header.accept`
Request parameter	`$request.path.id`	Request parameters MUST be declared in the `parameters` section of the parent operation or they cannot be evaluated. This includes request headers.
Request body property	`$request.body#/user/uuid`	In operations which accept payloads, references may be made to portions of the `requestBody` or the entire body.
Request URL	`$url`
Response value	`$response.body#/status`	In operations which return payloads, references may be made to portions of the response body or the entire body.
Response header	`$response.header.Server`	Single header values only are available
workflow input	`$inputs.username` or `$workflows.foo.inputs.username`	Single input values only are available
Step output value	`$steps.someStep.pets`	In situations where the output named property return payloads, references may be made to portions of the response body or the entire body.
Workflow output value	`$outputs.bar` or `$workflows.foo.outputs.bar`	Single input values only are available
Components parameter	`$components.parameters.foo`	Accesses a foo parameter defined within the Components Object.

Runtime expressions preserve the type of the referenced value. Expressions can be embedded into string values by surrounding the expression with {} curly braces.

Specification Extensions

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

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

Field Pattern	Type	Description
^x-	Any	Allows extensions to the Arazzo Specification. The field name MUST begin with `x-`, for example, `x-internal-id`. Field names beginning `x-oai-`, `x-oas-`, and `x-arazzo` are reserved for uses defined by the OpenAPI Initiative. The value MAY be `null`, a primitive, an array or an object.

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).

The Arazzo Specification v1.0.0

Status of This Document

Arazzo Specification

Version 1.0.0

Introduction

Definitions

Arazzo Description

Specification

Versions

Format

Arazzo Description Structure

Data Types

Relative References in URLs

Schema

Arazzo Specification Object

Fixed Fields

Arazzo Specification Object Example

Info Object

Fixed Fields

Info Object Example

Source Description Object

Fixed Fields

Source Description Object Example

Workflow Object

Fixed Fields

Workflow Object Example

Step Object

Fixed Fields

Step Object Example

Parameter Object

Fixed Fields

Parameter Object Example

Success Action Object

Fixed Fields

Success Action Object Example

Failure Action Object

Fixed Fields

Failure Action Object Example

Components Object

Fixed Fields

Components Object Example

Reusable Object

Fixed Fields

Reusable Object Example

Criterion Object

Literals

Operators

Fixed Fields

Criterion Object Example

Criterion Expression Type Object

Fixed Fields

Criterion Expression Type Example

Request Body Object

Fixed Fields

RequestBody Object Example

Payload Replacement Object

Fixed Fields

Payload Replacement Object Example

Runtime Expressions

Examples

Specification Extensions

Security Considerations

IANA Considerations

application/vnd.oai.workflows

application/vnd.oai.workflows+json

application/vnd.oai.workflows+yaml

Appendix A: Revision History