Mavenlink

Mavenlink Billing Milestones API

Billing milestones allow you to set up billable items in a project that are separate from the Task Tracker work and have invoicing rules. A set of billing milestones in a project is known as the [Billing Schedule](https://knowledge.kantata.com/hc/en-us/articles/35123275585947).

Documentation GitHub OpenAPI

Business capability

Accounts Receivable Management BC-200.30

Operations 5

GET /billing_milestones Fetching a list of Billing Milestones #

POST /billing_milestones Creating one or many Billing Milestones #

GET /billing_milestones/{id} Fetching a single Billing Milestone #

PUT /billing_milestones/{id} Updating an existing Billing Milestone #

DELETE /billing_milestones/{id} Deleting an existing Billing Milestones #

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OpenAPI Specification

openapi: 3.2.0
info:
  version: 1.0.0
  title: Kantata OX API Documentation Billing Milestones API
  description: Kantata OX's API provides access to the majority of Kantata OX's data model.
  termsOfService: https://www.kantata.com/terms-of-use
  contact:
    name: Kantata OX Support
    url: https://knowledge.kantata.com/hc/en-us
  license:
    name: COPYRIGHT © 2026 Kantata, Inc.
    url: https://www.kantata.com/terms-of-use
  x-logo:
    url: https://theme.zdassets.com/theme_assets/56104/04e93064d309f75d054b8cee885d1ea51e9be8f7.png
    backgroundColor: '#FFFFFF'
    altText: Kantata OX API Documentation
    href: https://developer.kantata.com
servers:
- url: https://api.mavenlink.com/api/v1
tags:
- name: Billing Milestones
  description: 'Billing milestones allow you to set up billable items in a project that are separate from the Task Tracker work and have invoicing rules.

    A set of billing milestones in a project is known as the Billing Schedule.'
paths:
  /billing_milestones:
    get:
      summary: Fetching a list of Billing Milestones
      description: 'Gets a list of billing milestones.


        This endpoint returns structured Billing Milestones objects.

        As with all Kantata OX API endpoints, the returned data will be referenced in sorted order in the `results` array

        and will be indexed by ID in the `billing_milestones` top-level JSON key.

        Please see our Response Format section for more information.'
      operationId: Get Billing Milestones
      tags:
      - Billing Milestones
      parameters:
      - in: query
        name: date_between
        description: Filter by a range of invoice dates. Format as `YYYY-MM-DD:YYYY-MM-DD`. The filter is inclusive.
        schema:
          type: string
      - in: query
        name: external_reference_external_message
        description: Filter the objects based on the external message of their associated external references. This is an exact match.
        schema:
          type: string
      - in: query
        name: external_reference_external_status
        description: Filter by the status of the external object in the external system.
        schema:
          type: string
      - in: query
        name: external_reference_service_model
        description: Filter by the type of the external object this external reference belongs to.
        schema:
          type: string
      - in: query
        name: external_reference_service_model_ref
        description: Filter by the id of the external object this external reference belongs to.
        schema:
          type: integer
          format: int32
      - in: query
        name: external_reference_service_model_refs
        description: Filter for objects that correlate to the specified external object IDs. Provide a comma-separated list of up to 200 external IDs.
        schema:
          type: string
      - in: query
        name: external_reference_service_name
        description: Filter by the name of the provider for integration.
        schema:
          type: string
      - in: query
        name: external_reference_status
        description: Filter by the status of the integration, this can be successful or fail.
        schema:
          type: string
      - in: query
        name: has_external_references
        description: Filter by whether or not the object has external references.
        schema:
          type: boolean
      - in: query
        name: include
        description: 'Any of the below associations can be included in your request by providing the `include` param, e.g. `include=association1,association2`.

          - `external_references` (ExternalReference) - Includes references to external integrations for this object.

          - `invoices` (Invoice) - Retrieves the invoices that the billing milestones are on. The response will include `invoice_ids`, which references the data in the `invoices` top-level key.

          - `story` (Story) - Retrieves the task associated with the billing milestone. The response will include `story_id`, which references the data in the `stories` top-level key.

          - `workspace` (Workspace) - Retrieves the project that the billing milestone is in. The response will include `workspace_id`, which references the data in the `workspaces` top-level key.'
        schema:
          type: string
      - in: query
        name: only
        description: 'Allows you to request one or more resources directly by ID. Multiple IDs can be supplied

          in a comma separated list, like `GET /api/v1/workspaces.json?only=5,6,7`.'
        schema:
          type: string
      - in: query
        name: order
        description: 'Supply `order` with the name of a valid sort field for the endpoint and a direction.


          Valid values: `created_at:asc` and `created_at:desc`.'
        schema:
          type: string
          default: created_at:desc
      - in: query
        name: page
        schema:
          type: integer
          format: int32
          default: 1
      - in: query
        name: per_page
        schema:
          type: integer
          format: int32
          default: 20
          maximum: 200
      - in: query
        name: story_ids
        description: Filter for billing milestones associated to specific tasks. Provide a comma-separated list of task IDs. For example, `10,20`.
        schema:
          type: string
      - in: query
        name: without_external_reference_service_name
        description: Exclude by the existence of an external reference with the specified service name.
        schema:
          type: string
      - in: query
        name: workspace_ids
        description: Filter by the workspace. Provide a comma-separated list of workspace IDs. For example, `10,20`.
        schema:
          type: string
      responses:
        '200':
          description: A list of Billing Milestones have been retrieved.
          content:
            application/json:
              schema:
                type: object
                properties:
                  count:
                    type: integer
                    format: int32
                  meta:
                    type: object
                    properties:
                      count:
                        type: integer
                        format: int32
                      page_count:
                        type: integer
                        format: int32
                      page_number:
                        type: integer
                        format: int32
                      page_size:
                        type: integer
                        format: int32
                  results:
                    type: array
                    items:
                      type: object
                      properties:
                        key:
                          type: string
                        id:
                          type: string
                  billing_milestones:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/BillingMilestone'
                  external_references:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/ExternalReference'
                  workspaces:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Workspace'
                  stories:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Story'
                  invoices:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Invoice'
        '400':
          description: Bad Request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '401':
          description: Unauthorized request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '403':
          description: Forbidden request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '404':
          description: Page Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '422':
          description: Unprocessable Entity
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '503':
          description: Service is unavailable
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
    post:
      summary: Creating one or many Billing Milestones
      description: 'Add a billing milestone to your Billing Schedule. Up to 100 billing milestones can be created in one request.


        This endpoint returns structured Billing Milestones objects.

        As with all Kantata OX API endpoints, the returned data will be referenced in sorted order in the `results` array

        and will be indexed by ID in the `billing_milestones` top-level JSON key.

        Please see our Response Format section for more information.'
      operationId: Create Billing Milestone
      tags:
      - Billing Milestones
      parameters:
      - in: query
        name: include
        description: 'Any of the below associations can be included in your request by providing the `include` param, e.g. `include=association1,association2`.

          - `external_references` (ExternalReference) - Includes references to external integrations for this object.

          - `invoices` (Invoice) - Retrieves the invoices that the billing milestones are on. The response will include `invoice_ids`, which references the data in the `invoices` top-level key.

          - `story` (Story) - Retrieves the task associated with the billing milestone. The response will include `story_id`, which references the data in the `stories` top-level key.

          - `workspace` (Workspace) - Retrieves the project that the billing milestone is in. The response will include `workspace_id`, which references the data in the `workspaces` top-level key.'
        schema:
          type: string
      responses:
        '200':
          description: Billing Milestones has been created.
          content:
            application/json:
              schema:
                type: object
                properties:
                  count:
                    type: integer
                    format: int32
                  meta:
                    type: object
                    properties:
                      count:
                        type: integer
                        format: int32
                      page_count:
                        type: integer
                        format: int32
                      page_number:
                        type: integer
                        format: int32
                      page_size:
                        type: integer
                        format: int32
                  results:
                    type: array
                    items:
                      type: object
                      properties:
                        key:
                          type: string
                        id:
                          type: string
                  billing_milestones:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/BillingMilestone'
                  external_references:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/ExternalReference'
                  workspaces:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Workspace'
                  stories:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Story'
                  invoices:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Invoice'
        '400':
          description: Bad Request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '401':
          description: Unauthorized request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '403':
          description: Forbidden request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '404':
          description: Page Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '422':
          description: Unprocessable Entity
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '503':
          description: Service is unavailable
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                billing_milestone:
                  type: object
                  properties:
                    title:
                      type: string
                      description: The title of the billing milestone.
                    amount_in_cents:
                      type: integer
                      format: int32
                      description: The billing milestone amount, in the subunits of the currency (e.g. cents for USD). Values can also be negative (e.g. `-10000`).
                    date_to_invoice:
                      type: string
                      format: date
                      description: The date that the billing milestone becomes invoiceable. The date must be in [ISO 8601](https://www.w3.org/TR/NOTE-datetime) format.
                    workspace_id:
                      type: integer
                      format: int32
                      description: The ID of the workspace associated with the billing milestone.
                    story_id:
                      type: integer
                      format: int32
                      description: The ID of the story associated with the billing milestone. This field is required when the `billing_type` is set to `upon_completion`.
                    billing_type:
                      type: string
                      description: The billing type of the milestone. Can be 'fixed_date' or 'upon_completion'.
                    external_reference:
                      type: object
                      description: 'Typically populated programmatically by a third party system via an integration, this is an optional

                        object that holds data from an external system. It connects objects in an external system with objects in

                        Kantata OX (for example, to connect a Jira issue to a Kantata OX Project).'
                      properties:
                        service_name:
                          type: string
                          description: The provider name of the integration. If you are adding multiple external references to the same object, the `service_name` must be unique.
                        service_model:
                          type: string
                          description: The object type of the external object this external reference belongs to.
                        service_model_ref:
                          type: string
                          description: The object ID of the external object this external reference belongs to.
                        status:
                          type: string
                          description: The status of the integration. Options are `successful`, `pending`,  or `failed`.
                        external_message:
                          type: string
                          description: The message on the external object.
                        external_link:
                          type: string
                          description: The link to the external object.
                        external_status:
                          type: string
                          description: The status of the external object in the external system.
                        locked:
                          type: boolean
                          description: Whether the subject is locked.
                      required:
                      - service_name
                      - service_model
                      - service_model_ref
                  required:
                  - title
                  - amount_in_cents
                  - workspace_id
                billing_milestones:
                  type: array
                  description: Add multiple billing milestones and their attributes in an array.
                  items:
                    type: object
                    properties:
                      title:
                        type: string
                        description: The title of the billing milestone.
                      amount_in_cents:
                        type: integer
                        format: int32
                        description: The billing milestone amount, in the subunits of the currency (e.g. cents for USD). Values can also be negative (e.g. `-10000`).
                      date_to_invoice:
                        type: string
                        format: date
                        description: The date that the billing milestone becomes invoiceable. The date must be in [ISO 8601](https://www.w3.org/TR/NOTE-datetime) format.
                      workspace_id:
                        type: integer
                        format: int32
                        description: The ID of the workspace associated with the billing milestone.
                      story_id:
                        type: integer
                        format: int32
                        description: The ID of the story associated with the billing milestone. This field is required when the `billing_type` is set to `upon_completion`.
                      billing_type:
                        type: string
                        description: The billing type of the milestone. Can be 'fixed_date' or 'upon_completion'.
                      external_reference:
                        type: object
                        description: 'Typically populated programmatically by a third party system via an integration, this is an optional

                          object that holds data from an external system. It connects objects in an external system with objects in

                          Kantata OX (for example, to connect a Jira issue to a Kantata OX Project).'
                        properties:
                          service_name:
                            type: string
                            description: The provider name of the integration. If you are adding multiple external references to the same object, the `service_name` must be unique.
                          service_model:
                            type: string
                            description: The object type of the external object this external reference belongs to.
                          service_model_ref:
                            type: string
                            description: The object ID of the external object this external reference belongs to.
                          status:
                            type: string
                            description: The status of the integration. Options are `successful`, `pending`,  or `failed`.
                          external_message:
                            type: string
                            description: The message on the external object.
                          external_link:
                            type: string
                            description: The link to the external object.
                          external_status:
                            type: string
                            description: The status of the external object in the external system.
                          locked:
                            type: boolean
                            description: Whether the subject is locked.
                        required:
                        - service_name
                        - service_model
                        - service_model_ref
                    required:
                    - title
                    - amount_in_cents
                    - workspace_id
        required: true
  /billing_milestones/{id}:
    get:
      summary: Fetching a single Billing Milestone
      description: 'Gets a single billing milestone.


        This endpoint returns structured Billing Milestones objects.

        As with all Kantata OX API endpoints, the returned data will be referenced in sorted order in the `results` array

        and will be indexed by ID in the `billing_milestones` top-level JSON key.

        Please see our Response Format section for more information.'
      operationId: Get Billing Milestone
      tags:
      - Billing Milestones
      parameters:
      - in: path
        name: id
        required: true
        description: The ID of the Model.
        schema:
          type: integer
      - in: query
        name: include
        description: 'Any of the below associations can be included in your request by providing the `include` param, e.g. `include=association1,association2`.

          - `external_references` (ExternalReference) - Includes references to external integrations for this object.

          - `invoices` (Invoice) - Retrieves the invoices that the billing milestones are on. The response will include `invoice_ids`, which references the data in the `invoices` top-level key.

          - `story` (Story) - Retrieves the task associated with the billing milestone. The response will include `story_id`, which references the data in the `stories` top-level key.

          - `workspace` (Workspace) - Retrieves the project that the billing milestone is in. The response will include `workspace_id`, which references the data in the `workspaces` top-level key.'
        schema:
          type: string
      responses:
        '200':
          description: The Billing Milestones has been retrieved.
          content:
            application/json:
              schema:
                type: object
                properties:
                  count:
                    type: integer
                    format: int32
                  meta:
                    type: object
                    properties:
                      count:
                        type: integer
                        format: int32
                      page_count:
                        type: integer
                        format: int32
                      page_number:
                        type: integer
                        format: int32
                      page_size:
                        type: integer
                        format: int32
                  results:
                    type: array
                    items:
                      type: object
                      properties:
                        key:
                          type: string
                        id:
                          type: string
                  billing_milestones:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/BillingMilestone'
                  external_references:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/ExternalReference'
                  workspaces:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Workspace'
                  stories:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Story'
                  invoices:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Invoice'
        '400':
          description: Bad Request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '401':
          description: Unauthorized request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '403':
          description: Forbidden request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '404':
          description: Page Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '422':
          description: Unprocessable Entity
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '503':
          description: Service is unavailable
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
    put:
      summary: Updating an existing Billing Milestone
      description: 'Edit information for a billing milestone in your Billing Schedule. You can only edit billing milestones that have not been invoiced.


        This endpoint returns structured Billing Milestones objects.

        As with all Kantata OX API endpoints, the returned data will be referenced in sorted order in the `results` array

        and will be indexed by ID in the `billing_milestones` top-level JSON key.

        Please see our Response Format section for more information.'
      operationId: Update Billing Milestone
      tags:
      - Billing Milestones
      parameters:
      - in: path
        name: id
        required: true
        description: The ID of the Model.
        schema:
          type: integer
      - in: query
        name: include
        description: 'Any of the below associations can be included in your request by providing the `include` param, e.g. `include=association1,association2`.

          - `external_references` (ExternalReference) - Includes references to external integrations for this object.

          - `invoices` (Invoice) - Retrieves the invoices that the billing milestones are on. The response will include `invoice_ids`, which references the data in the `invoices` top-level key.

          - `story` (Story) - Retrieves the task associated with the billing milestone. The response will include `story_id`, which references the data in the `stories` top-level key.

          - `workspace` (Workspace) - Retrieves the project that the billing milestone is in. The response will include `workspace_id`, which references the data in the `workspaces` top-level key.'
        schema:
          type: string
      responses:
        '200':
          description: Billing Milestones has been updated.
          content:
            application/json:
              schema:
                type: object
                properties:
                  count:
                    type: integer
                    format: int32
                  meta:
                    type: object
                    properties:
                      count:
                        type: integer
                        format: int32
                      page_count:
                        type: integer
                        format: int32
                      page_number:
                        type: integer
                        format: int32
                      page_size:
                        type: integer
                        format: int32
                  results:
                    type: array
                    items:
                      type: object
                      properties:
                        key:
                          type: string
                        id:
                          type: string
                  billing_milestones:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/BillingMilestone'
                  external_references:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/ExternalReference'
                  workspaces:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Workspace'
                  stories:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Story'
                  invoices:
                    type: object
                    additionalProperties:
                      $ref: '#/components/schemas/Invoice'
        '400':
          description: Bad Request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '401':
          description: Unauthorized request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '403':
          description: Forbidden request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '404':
          description: Page Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '422':
          description: Unprocessable Entity
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
        '503':
          description: Service is unavailable
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Errors'
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                billing_milestone:
                  type: object
                  properties:
                    title:
                      type: string
                      description: The title of the billing milestone.
                    amount_in_cents:
                      type: integer
                      format: int32
                      description: The billing milestone amount, in the subunits of the currency (e.g. cents for USD).
                    date_to_invoice:
                      type: string
                      format: date
                      description: The date that the billing milestone becomes invoiceable. The date must be in [ISO 8601](https://www.w3.org/TR/NOTE-datetime) format.
                    billing_type:
                      type: string
                      description: The billing type of the milestone. Can be 'fixed_date' or 'upon_completion'.
                    story_id:
                      type: integer
                      format: int32
                      description: The ID of the story associated with the billing milestone. This field is required when the `billing_type` is set to `upon_completion`.
                    external_reference:
                      type: object
                      description: 'Typically populated programmatically by a third party system via an integration, this is an optional

                        object that holds data from an external system. It connects objects in an external system with objects in

                        Kantata OX (for example, to connect a Jira issue to a Kantata OX Project).'
                      properties:
                        service_name:
                          type: string
                          description: The provider name of the integration. If you are addi

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