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Arazzo: OpenAPI Workflows

The Arazzo Specification is a new addition to the OpenAPI Specification that allows you to define sequences of operations for your API.

An Arazzo description is a separate document that references your OpenAPI document and describes how to combine operations from your OpenAPI document into step-by-step sequences.

Arazzo descriptions are useful for:

  • Defining complex sequences of operations that involve multiple API calls.
  • Documenting the expected behavior of your API in a more structured way than a narrative description.
  • Generating code to execute the sequences of operations.
  • Generating tests to verify that the sequences of operations behave as expected.
  • Generating documentation that explains how to use the sequences of operations.

Arazzo Description Structure

An Arazzo description is a JSON or YAML document that follows the structure defined by the Arazzo Specification.

Arazzo version

Field NameTypeRequired
arazzostring✅

The version of the Arazzo Specification that the document uses. The value must be a supported version number.

workflowsSpec: 1.0.0-prerelease

Info metadata

Field NameTypeRequired
infoInfo Object✅

Provides metadata about the Arazzo description.

info:
  title: Speakeasy Bar Workflows
  summary: Workflows for managing the Speakeasy Bar API
  description: >
    This document defines workflows for managing the [Speakeasy Bar API](https://bar.example.com), including
    creating new drinks, managing inventory, and processing orders.
  version: 4.6.3

Source description

Field NameTypeRequired
sourceDescriptions[Source Description Object]✅

An array of source description objects defining the OpenAPI or other documents containing the operations referenced by the workflows. The array must contain at least one source.

sourceDescriptions:
  - name: speakeasyBar
    url: https://bar.example.com/openapi.yaml
    type: openapi
  - name: printsAndBeeps
    url: https://output.example.com/workflows.yaml
    type: workflowsSpec

Workflows

Field NameTypeRequired
workflows[Workflow Object]✅

An array of workflow objects defining the workflows. The array must contain at least one workflow.

workflows:
  - workflowId: createDrink
    summary: Create a new drink in the bar's menu
    inputs:
      allOf:
        - $ref: "#/components/inputs/authenticate"
        - type: object
          properties:
            drink_name:
              type: string
            drink_type:
              type: string
            drink_price_usd_cent:
              type: integer
            ingredients:
              type: array
              items:
                type: string
    steps:
      - stepId: authenticate
        operationId: authenticate
        parameters:
          - reference: $components.parameters.username
          - reference: $components.parameters.password
      - stepId: createDrink
        operationId: createDrink
        parameters:
          - reference: $components.parameters.authorization
          - name: name
            in: query
            value: $inputs.drink_name
          - name: type
            in: query
            value: $inputs.drink_type
          - name: price
            in: query
            value: $inputs.drink_price_usd_cent
          - name: ingredients
            in: query
            value: $inputs.ingredients
  - workflowId: makeDrink
    summary: Order a drink and check the order status
    inputs:
      - name: orderType
        description: The type of order
        type: string
        required: true
      - name: productCode
        description: The product code of the drink
        type: string
        required: true
      - name: quantity
        description: The quantity of the drink
        type: integer
        required: true
    steps:
      - stepId: orderDrink
        operationId: createOrder
        parameters:
          - name: orderType
            in: body
            value: $inputs.orderType
          - name: productCode
            in: body
            value: $inputs.productCode
          - name: quantity
            in: body
            value: $inputs.quantity
      - stepId: checkStatus
        operationId: getOrder
        parameters:
          - name: orderNumber
            in: path
            value: $orderDrink.orderNumber
        successCriteria:
          - type: simple
            condition: $checkStatus.status == 'completed'
        onSuccess:
          - name: printReceipt
            type: goto
            workflowId: $sourceDescriptions.printsAndBeeps.printReceipt
            criteria:
              - type: simple
                condition: $checkStatus.status == 'completed'
        onFailure:
          - name: beepLoudly
            type: goto
            workflowId: $sourceDescriptions.printsAndBeeps.beepLoudly
            criteria:
              - type: simple
                condition: $checkStatus.status == 'failed'
  - workflowId: addIngredient
    summary: Add a new ingredient to the bar's inventory
    inputs:
      - name: username
        description: The username of the manager
        type: string
        required: true
      - name: password
        description: The password of the manager
        type: string
        required: true
      - name: ingredient_name
        description: The name of the ingredient
        type: string
        required: true
      - name: ingredient_type
        description: The type of the ingredient
        type: string
        required: true
      - name: ingredient_stock
        description: The stock of the ingredient
        type: integer
        required: true
      - name: productCode
        description: The product code of the ingredient
        type: string
        required: true
    steps:
      - stepId: authenticate
        operationId: authenticate
        parameters:
          - reference: $components.parameters.username
            value: admin
          - reference: $components.parameters.password
      - stepId: addIngredient
        operationId: createIngredient
        parameters:
          - reference: $components.parameters.authorization
          - name: name
            in: query
            value: $inputs.ingredient_name
          - name: type
            in: query
            value: $inputs.ingredient_type
          - name: stock
            in: query
            value: $inputs.ingredient_stock
          - name: productCode
            in: query
            value: $inputs.productCode
components:
  inputs:
    authenticate:
      type: object
      properties:
        username:
          type: string
        password:
          type: string
  parameters:
    authorization:
      name: Authorization
      in: header
      value: $authenticate.outputs.token
    username:
      name: username
      in: body
      value: $inputs.username
    password:
      name: password
      in: body
      value: $inputs.password

This table shows all fields at the root of the Arazzo Specification:

Field Name
arazzo
Type
string
Description
The version of the Arazzo Specification that the document uses. The value must be a supported version number.
Required
✅
info
Description
Provides metadata about the Arazzo description.
Required
✅
sourceDescriptions
Description
An array of source description objects defining the OpenAPI or other documents containing the operations referenced by the workflows. The array must contain at least one source.
Required
✅
workflows
Description
An array of workflow objects defining the workflows. The array must contain at least one workflow.
Required
✅
components
Description
An element to hold reusable schemas for the workflow, for example, inputs and parameters.
Required
x-*
Description
Any number of extension fields can be added to the Arazzo description that can be used by tooling and vendors. When provided at this level, the extensions generally apply to the entire document.
Required

Arazzo Specification Versions

The arazzo field contains the version number of the Arazzo Specification that the document conforms to. Tooling should use this value to interpret the document correctly.

The current version of the Arazzo Specification is 1.0.0-prerelease, but keep in mind that the specification is still under development.

Info Object

Provides metadata about the Arazzo description.

Field Name
title
Type
string
Description
A human-readable title for the set of workflows.
Required
✅
summary
Type
string
Description
A short summary of the Arazzo description.
Required
description
Type
string
Description
A longer description of the Arazzo description. CommonMark syntax may be used for rich text representation.
Required
version
Type
string
Description
A version string indicating the version of the Arazzo document.
Required
✅
x-*
Description
Any number of extension fields can be added that can be used by tooling and vendors.
Required

Below is an example of an info object in an Arazzo document:

info:
  title: Speakeasy Bar Workflows
  summary: Workflows for managing the Speakeasy Bar API
  description: >
    This document defines workflows for managing the [Speakeasy Bar API](https://bar.example.com), including
    creating new drinks, managing inventory, and processing orders.
  version: 4.6.3

Source Description Object

A source description points to an OpenAPI document containing the operations referenced by the workflows in this document. It may also reference other Arazzo documents.

Field Name
name
Type
string
Description
A name for the source document, used to reference it from other parts of the Arazzo description. The name must be unique within the sourceDescriptions array and may only contain alphanumeric characters, underscores, and dashes.
Required
✅
url
Type
string
Description
The URL of the source document. This identifier must conform to RFC 3986 section 4.1 for absolute URLs or section 4.2 for relative URIs.
Required
✅
type
Type
string
Description
The type of the source document. Supported values are openapi, indicating an OpenAPI document, or arazzo indicating another Arazzo description. Additional values may be supported in future versions of the specification.
Required
x-*
Description
Any number of extension fields can be added to the source description object that can be used by tooling and vendors.
Required

Below is an example of two source description objects in an Arazzo description document:

sourceDescriptions:
  - name: speakeasyBar
    url: https://bar.example.com/openapi.yaml
    type: openapi
  - name: printsAndBeeps
    url: https://output.example.com/workflows.yaml
    type: workflowsSpec

Workflow Object

A workflow object defines a sequence of operations.

Field Name
workflowId
Type
string
Description
A unique identifier for the workflow. This is used to reference the workflow from other parts of the Arazzo description. May contain only alphanumeric characters, underscores, and dashes.
Required
✅
summary
Type
string
Description
A short summary of what the workflow does.
Required
description
Type
string
Description
A longer description of the workflow. CommonMark syntax may be used for rich text representation.
Required
inputs
Description
A schema defining the input parameters for the workflow.
Required
dependsOn
Type
[string]
Description
An array of workflow IDs that this workflow depends on. The workflows in the array must be executed before this workflow.
Required
steps
Description
An ordered array of step objects defining the steps of the workflow. The array must contain at least one step.
Required
✅
successActions
Description
An array of success action objects and reusable objects specifying actions to take for each step of this workflow that completes successfully. Individual steps may override the workflow object's success actions. Reusable objects must reference success actions defined in the components/successActions of this Arazzo document.
Required
failureActions
Description
An array of failure action objects and reusable objects specifying actions to take for each step of this workflow that fails. Individual steps may override the workflow object's failure actions. Reusable objects must reference success actions defined in the components/failureActions of this Arazzo document.
Required
outputs
Type
Map[string, {Runtime Expression}]
Description
A map of output values produced by the workflow. The keys are the names of the outputs, and the values are runtime expressions that extract the output values from the results of the workflow steps.
Required
parameters
Description
An array of parameters applicable to all steps in this workflow. Individual steps may override the workflow object's parameters. A reusable object must reference an object in this document's components/parameters of this Arazzo document.
Required
x-*
Description
Any number of extension fields can be added to the workflow object that can be used by tooling and vendors.
Required

Below is an example of a workflow object:

workflows:
  - workflowId: createDrink
    summary: Create a new drink in the bar's menu
    inputs:
      allOf:
        - $ref: "#/components/inputs/authenticate"
        - type: object
          properties:
            drink_name:
              type: string
            drink_type:
              type: string
            drink_price_usd_cent:
              type: integer
            ingredients:
              type: array
              items:
                type: string
    steps:
      - stepId: authenticate
        operationId: authenticate
        parameters:
          - reference: $components.parameters.username
          - reference: $components.parameters.password
      - stepId: createDrink
        operationId: createDrink
        parameters:
          - reference: $components.parameters.authorization
          - name: name
            in: query
            value: $inputs.drink_name
          - name: type
            in: query
            value: $inputs.drink_type
          - name: price
            in: query
            value: $inputs.drink_price_usd_cent
          - name: ingredients
            in: query
            value: $inputs.ingredients
  - workflowId: makeDrink
    summary: Order a drink and check the order status
    inputs:
      - name: orderType
        description: The type of order
        type: string
        required: true
      - name: productCode
        description: The product code of the drink
        type: string
        required: true
      - name: quantity
        description: The quantity of the drink
        type: integer
        required: true
    steps:
      - stepId: orderDrink
        operationId: createOrder
        parameters:
          - name: orderType
            in: body
            value: $inputs.orderType
          - name: productCode
            in: body
            value: $inputs.productCode
          - name: quantity
            in: body
            value: $inputs.quantity
      - stepId: checkStatus
        operationId: getOrder
        parameters:
          - name: orderNumber
            in: path
            value: $orderDrink.orderNumber
        successCriteria:
          - type: simple
            condition: $checkStatus.status == 'completed'
        onSuccess:
          - name: printReceipt
            type: goto
            workflowId: $sourceDescriptions.printsAndBeeps.printReceipt
            criteria:
              - type: simple
                condition: $checkStatus.status == 'completed'
        onFailure:
          - name: beepLoudly
            type: goto
            workflowId: $sourceDescriptions.printsAndBeeps.beepLoudly
            criteria:
              - type: simple
                condition: $checkStatus.status == 'failed'
  - workflowId: addIngredient
    summary: Add a new ingredient to the bar's inventory
    inputs:
      - name: username
        description: The username of the manager
        type: string
        required: true
      - name: password
        description: The password of the manager
        type: string
        required: true
      - name: ingredient_name
        description: The name of the ingredient
        type: string
        required: true
      - name: ingredient_type
        description: The type of the ingredient
        type: string
        required: true
      - name: ingredient_stock
        description: The stock of the ingredient
        type: integer
        required: true
      - name: productCode
        description: The product code of the ingredient
        type: string
        required: true
    steps:
      - stepId: authenticate
        operationId: authenticate
        parameters:
          - reference: $components.parameters.username
            value: admin
          - reference: $components.parameters.password
      - stepId: addIngredient
        operationId: createIngredient
        parameters:
          - reference: $components.parameters.authorization
          - name: name
            in: query
            value: $inputs.ingredient_name
          - name: type
            in: query
            value: $inputs.ingredient_type
          - name: stock
            in: query
            value: $inputs.ingredient_stock
          - name: productCode
            in: query
            value: $inputs.productCode

Step Object

A step object defines a single operation to perform as part of a workflow.

Field Name
stepId
Type
string
Description
A unique identifier for the step within the workflow. Used to reference the step's outputs from other parts of the workflow. May contain only alphanumeric characters, underscores, and dashes.
Required
✅
description
Type
string
Description
A description of what the step does. CommonMark syntax may be used for rich text representation.
Required
operationId
Type
string
Description
The operationId of the operation to execute for this step. Must match an operationId in one of the sourceDescriptions. This field is mutually exclusive with operationPath and workflowId.
Required
operationPath
Type
string
Description
A JSON Pointer to the operation to execute for this step, relative to one of the sourceDescriptions. This field is mutually exclusive with operationId and workflowId.
Required
workflowId
Type
string
Description
The ID of a workflow in this document to execute as a sub-workflow. This field is mutually exclusive with operationId and operationPath.
Required
parameters
Description
An array of parameters to pass to the operation for this step. Overrides any parameters defined at the workflow level.
Required
requestBody
Description
The request body to send for the operation.
Required
successCriteria
Description
An array of criteria for determining if the step succeeded. All criteria must be met for the step to be considered successful. Individual criteria are defined using criterion objects.
Required
onSuccess
Description
An array of actions to take if the step succeeds. Overrides any success actions defined at the workflow level. Individual actions are defined using success action objects.
Required
onFailure
Description
An array of actions to take if the step fails. Overrides any failure actions defined at the workflow level. Individual actions are defined using failure action objects.
Required
outputs
Type
Map[string, {Runtime Expression}]
Description
A map of output values produced by the step. The keys are the names of the outputs, and the values are runtime expressions that extract the output values from the result of the operation.
Required
x-*
Description
Any number of extension fields can be added to the step object that can be used by tooling and vendors.
Required

Below is an example of step objects in an Arazzo description document:

steps:
      - stepId: orderDrink
        operationId: createOrder
        parameters:
          - name: orderType
            in: body
            value: $inputs.orderType
          - name: productCode
            in: body
            value: $inputs.productCode
          - name: quantity
            in: body
            value: $inputs.quantity

Parameter Object

A parameter object defines a single parameter to pass to an operation in a workflow step.

Field Name
name
Type
string
Description
The name of the parameter.
Required
✅
in
Type
string
Description
The location of the parameter. Possible values are path, query, header, cookie. Required for parameters passed to an operation. Must be omitted for parameters passed to a workflow, where the parameter is always passed in the workflow's inputs object. See Parameter Location.
Required
✅
value
Type
Any | {Runtime Expression}
Description
The value of the parameter. Can be a literal value, or a runtime expression that will be evaluated and passed to the operation or workflow.
Required
x-*
Description
Any number of extension fields can be added to the parameter object that can be used by tooling and vendors.
Required

Parameter Location

For parameters passed to an operation, the in field specifies the location of the parameter. The possible values are:

  • path - The parameter is part of the operation’s URL path.
  • query - The parameter is appended to the operation’s URL as a query parameter.
  • header - The parameter is sent in the request headers.
  • cookie - The parameter is sent in a cookie.

For parameters passed to a workflow, the in field must be omitted. Workflow parameters are always passed in the workflow’s inputs object.

Arazzo Parameter Object Examples

parameters:
  - reference: $components.parameters.authorization
  - name: name
    in: query
    value: $inputs.drink_name
  - name: type
    in: query
    value: $inputs.drink_type
  - name: price
    in: query
    value: $inputs.drink_price_usd_cent
  - name: ingredients
    in: query
    value: $inputs.ingredients

Success Action Object

A success action object defines an action to take when a workflow step succeeds.

Field Name
name
Type
string
Description
The name of the action. Names are case-sensitive and must be unique within the successActions array of a step or workflow.
Required
✅
type
Type
string
Description
The type of action to take. Possible values are:
  • end - End the workflow.
  • goto - Move to another step in the workflow. Requires either stepId or workflowId to be specified.
Required
✅
stepId
Type
string
Description
The stepId of the step to execute next if type is goto. Mutually exclusive with workflowId.
Required
workflowId
Type
string
Description
The workflowId of the workflow to execute if type is goto. Mutually exclusive with stepId.
Required
criteria
Description
An array of criteria that determine whether the action should be executed. All criteria must be met for the action to execute. If not provided, the action will always execute.
Required
x-*
Description
Any number of extension fields can be added to the success action object that can be used by tooling and vendors.
Required

Below is an example of a success action object:

onSuccess:
  - name: printReceipt
    type: goto
    workflowId: $sourceDescriptions.printsAndBeeps.printReceipt
    criteria:
      - type: simple
        condition: $checkStatus.status == 'completed'

Failure Action Object

A failure action object defines an action to take when a workflow step fails.

Field Name
name
Type
string
Description
The name of the action. Names are case-sensitive and must be unique within the failureActions array of a step or workflow.
Required
✅
type
Type
string
Description
The type of action to take. Possible values are:
  • end - End the workflow, returning the specified outputs if provided.
  • goto - Move to another step in the workflow. Requires either stepId or workflowId to be specified.
  • retry - Retry the failed step. Requires retryAfter and optionally retryLimit to be specified.
Required
✅
stepId
Type
string
Description
The stepId of the step to execute next if type is goto. Mutually exclusive with workflowId.
Required
workflowId
Type
string
Description
The workflowId of the workflow to execute if type is goto. Mutually exclusive with stepId.
Required
retryAfter
Type
Number
Description
The number of seconds to wait before retrying the failed step if type is retry. Must be a non-negative integer. The specification is ambiguous about whether this field also applies when type is goto.
Required
retryLimit
Type
Integer
Description
The maximum number of times to retry the failed step if type is retry. Must be a non-negative integer. If not provided, the step will be retried indefinitely until it succeeds or the workflow is canceled.
Required
criteria
Description
An array of criteria that determine whether the action should be executed. All criteria must be met for the action to execute.
Required
x-*
Description
Any number of extension fields can be added to the failure action object that can be used by tooling and vendors.
Required

Below is an example of a failure action object:

onFailure:
  - name: beepLoudly
    type: goto
    workflowId: $sourceDescriptions.printsAndBeeps.beepLoudly
    criteria:
      - type: simple
        condition: $checkStatus.status == 'failed'

Components Object

The components object holds reusable objects that can be referenced from other parts of the Arazzo description.

Field Name
inputs
Type
Map[string, JSON Schema]
Description
An object containing reusable JSON Schemas that can be referenced from workflow inputs.
Required
parameters
Type
Map[string, Parameter Object]
Description
An object containing reusable parameter objects.
Required
successActions
Type
Map[string, Success Action Object]
Description
An object containing reusable success action objects.
Required
failureActions
Type
Map[string, Failure Action Object]
Description
An object containing reusable failure action objects.
Required
x-*
Description
Any number of extension fields can be added to the components object that can be used by tooling and vendors.
Required

The keys in the components object may only contain alphanumeric characters, underscores, and dashes.

Arazzo Components Object Example

components:
  inputs:
    authenticate:
      type: object
      properties:
        username:
          type: string
        password:
          type: string
  parameters:
    authorization:
      name: Authorization
      in: header
      value: $authenticate.outputs.token
    username:
      name: username
      in: body
      value: $inputs.username
    password:
      name: password
      in: body
      value: $inputs.password

The components defined in an Arazzo description are scoped to that document. Components defined in one Arazzo description cannot be referenced from another Arazzo description.

Reusable Object

A reusable object allows you to reference objects like success actions and failure actions defined in the components object from locations within steps or workflows.

Field Name
reference
Description
A runtime expression used to reference the desired object from the components object.
Required
✅
value
Type
string
Description
The value of the referenced parameter. Only used for parameters.
Required

Arazzo Reusable Object Example

- reference: $components.parameters.username
  value: admin
- reference: $components.parameters.password

Criterion Object

A criterion object is used to specify assertions in the successCriteria field of a step object, or the criteria field of a success action object or failure action object.

Criterion objects support three types of assertions:

  • simple - Basic comparisons using literals, operators, and runtime expressions. This is the default if no type is specified.
  • regex - Applies a regular expression pattern to a context defined by a runtime expression.
  • JSONPath - Applies a JSONPath expression to a context defined by a runtime expression. The root node of the JSONPath is the context.

Literals

Literals are constant values that can be used in simple conditions. The following data types are supported:

Type
boolean
Literal Value
true or false
null
Literal Value
null
number
Literal Value
A number of type int32, int64, float, or double.
string
Literal Value
Strings must be enclosed in single quotes ('). To include a literal single quote, escape it with another single quote ('').

Operators

Simple conditions support the following operators:

Operator
<
Description
Less than
<=
Description
Less than or equal
>
Description
Greater than
>=
Description
Greater than or equal
==
Description
Equal
!=
Description
Not equal
!
Description
Not
&&
Description
And
||
Description
Or
()
Description
Grouping
[]
Description
Array index (0-based)
.
Description
Property dereference

String comparisons are case-insensitive.

A criterion object consists of the following fields:

Field Name
context
Description
A runtime expression that defines the context for regex and JSONPath conditions. Must be provided if type is specified.
Required
condition
Type
string
Description
The assertion to evaluate. For simple conditions, combines literals, operators, and runtime expressions. For regex and JSONPath conditions, provides the expression to evaluate against the context.
Required
✅
type
Type
string
Description
The type of assertion. Allowed values are simple, regex, or JSONPath. Defaults to simple if not provided.
Required
x-*
Description
Any number of extension fields can be added to the criterion object that can be used by tooling and vendors.
Required

Arazzo Criterion Object Examples

Simple Condition - Check if a drink was successfully created

- condition: $statusCode == 201

Simple Condition - Check if the bar is open

- condition: $response.body#/isOpen == true

Regex Condition - Check if the drink name matches a pattern

- context: $response.body#/drinkName
  condition: "^Sazerac"
  type: regex

JSONPath Condition - Check if the ingredient list contains “whiskey”

- context: $response.body
  condition: $..ingredients[?(@.name == 'whiskey')]
  type: JSONPath

Simple Condition - Check if the customer is over 21

- condition: $response.body#/customer/age >= 21

JSONPath Condition - Check if there are any available tables

- context: $response.body
  condition: $[?length(@.tables[?(@.available == true)]) > 0]
  type: JSONPath

Request Body Object

The request body object describes the payload and Content-Type to send with the request when executing an operation in a workflow step.

Field Name
contentType
Type
string
Description
The Content-Type header for the request payload. If omitted, defaults to the Content-Type of the referenced operation.
Required
payload
Type
Any
Description
The literal payload value to send in the request body. Can contain runtime expressions which will be evaluated before sending the request.
Required
replacements
Description
An array of payload replacement objects specifying values to insert into specific locations in the payload.
Required
x-*
Description
Any number of extension fields can be added to the request body object that can be used by tooling and vendors.
Required

Request Body Object Examples

JSON Payload (Template)

contentType: application/json
payload: |
  {
    "order": {
      "drinkId": "{$inputs.drink_id}",
      "customerId": "{$inputs.customer_id}",
      "quantity": {$inputs.quantity}
    }
  }

JSON Payload (Object)

contentType: application/json
payload:
  order:
    drinkId: $inputs.drink_id
    customerId: $inputs.customer_id
    quantity: $inputs.quantity

JSON Payload (Runtime Expression)

contentType: application/json
payload: $inputs.orderPayload

XML Payload (Template)

contentType: application/xml
payload: |
  <order>
    <drinkId>{$inputs.drink_id}</drinkId>
    <customerId>{$inputs.customer_id}</customerId>
    <quantity>{$inputs.quantity}</quantity>
  </order>

Form Data Payload (Object)

contentType: application/x-www-form-urlencoded
payload:
  drinkId: $inputs.drink_id
  customerId: $inputs.customer_id
  quantity: $inputs.quantity

Form Data Payload (String)

contentType: application/x-www-form-urlencoded
payload: "drinkId={$inputs.drink_id}&customerId={$inputs.customer_id}&quantity={$inputs.quantity}"

Payload Replacement Object

A payload replacement object specifies a location within the request payload and the value to insert at that location.

Field Name
target
Type
string
Description
A JSON Pointer or XPath expression that identifies the location in the payload to insert the value. For JSON payloads, use JSON Pointer. For XML payloads, use XPath.
Required
✅
value
Type
Any
Description
The value to insert at the specified target location. Can be a literal or a runtime expression that will be evaluated before sending the request.
Required
✅
x-*
Description
Any number of extension fields can be added to the payload replacement object that can be used by tooling and vendors.
Required

Payload Replacement Object Examples

Runtime Expression Value

target: /drinkId
value: $inputs.drink_id

Literal Value

target: /quantity
value: 2

Runtime Expressions

Runtime expressions allow you to reference values that will be available when a workflow is executed, such as values from the HTTP request or response, the event that triggered the workflow, or outputs from previous workflow steps.

The syntax for runtime expressions is {expression}, where expression is one of the following:

Expression
$url
Description
The full URL of the request
$method
Description
The HTTP method of the request
$statusCode
Description
The HTTP status code of the response
$request.header.{name}
Description
The value of the specified request header
$request.query.{name}
Description
The value of the specified query parameter from the request URL
$request.path.{name}
Description
The value of the specified path parameter from the request URL
$request.body
Description
The entire request body
$request.body#/path/to/property
Description
The value of the specified JSON pointer path from the request body
$response.header.{name}
Description
The value of the specified response header
$response.body
Description
The entire response body
$response.body#/path/to/property
Description
The value of the specified JSON pointer path from the response body
$inputs.{name}
Description
The value of the specified workflow input
$outputs.{name}
Description
The value of the specified workflow output
$steps.{stepId}.{outputName}
Description
The value of the specified output from the step with ID {stepId}
$workflows.{id}.{inputName}
Description
The value of the specified input from the workflow with ID {id}
$workflows.{id}.{outputName}
Description
The value of the specified output from the workflow with ID {id}

Runtime Expression Examples

Expression
$request.header.Authorization
Example Value
Bearer abc123
$request.query.drinkId
Example Value
12345
$response.body#/drinks/0/name
Example Value
"Negroni"
$inputs.orderType
Example Value
"pickup"
$steps.submitOrder.outputs.orderId
Example Value
"a8b9c6d4e5f001"

Arazzo Specification Extensions

The Arazzo Specification allows custom properties to be added at certain points using specification extensions.

Extension properties are always prefixed by "x-" and can have any valid JSON value.

For example:

x-internal-id: abc123
x-vendor-parameter:
  vendorId: 123
  channelId: abc

The extensions defined by the Arazzo Specification are:

Context
Arazzo Description
Description
Applies to the entire Arazzo description document
Info Object
Description
Applies to the info object
Source Description Object
Description
Applies to all the source description objects
Workflow Object
Description
Applies to all workflow objects
Step Object
Description
Applies to all step objects
Parameter Object
Description
Applies to all parameter objects
Success Action Object
Description
Applies to all success action objects
Failure Action Object
Description
Applies to all failure action objects
Criterion Object
Description
Applies to all criterion objects
Request Body Object
Description
Applies to all request body objects
Payload Replacement Object
Description
Applies to all payload replacement objects
Reusable Object
Description
Applies to all reusable objects
Components Object
Description
Applies to the components object

The specification extension key formats ^x-oai- and ^x-oas- are reserved for extensions defined by the OpenAPI Initiative.

Extension properties can be used to add additional features, metadata, or configuration options to the Arazzo description that are not directly supported by the current version of the specification. However, additional tooling may be required to process custom extensions.