Microsoft Project Custom Fields API

openapi: 3.0.3
info:
  title: Microsoft Project Online REST Assignments Custom Fields API
  description: REST API for accessing and managing Microsoft Project Online and Project Server data including projects, tasks, resources, assignments, calendars, custom fields, timesheets, lookup tables, and workflow activities. Uses SharePoint-based REST endpoints via the ProjectServer service.
  version: '1.0'
  contact:
    name: Microsoft Project Support
    url: https://support.microsoft.com/
  license:
    name: Microsoft API License
    url: https://www.microsoft.com/en-us/legal/terms-of-use
  x-generated-from: documentation
  x-last-validated: '2026-04-18'
servers:
- url: https://{tenant}.sharepoint.com/sites/pwa/_api/ProjectServer
  description: Project Online REST API
  variables:
    tenant:
      default: contoso
      description: SharePoint tenant name
security:
- oauth2: []
tags:
- name: Custom Fields
  description: Manage enterprise custom field definitions
paths:
  /CustomFields:
    get:
      operationId: listCustomFields
      summary: Microsoft Project List Custom Fields
      description: Retrieve all enterprise custom field definitions.
      tags:
      - Custom Fields
      responses:
        '200':
          description: List of custom fields
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CustomFieldCollection'
      x-microcks-operation:
        delay: 0
        dispatcher: FALLBACK
    post:
      operationId: createCustomField
      summary: Microsoft Project Create Custom Field
      description: Create a new enterprise custom field definition.
      tags:
      - Custom Fields
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CustomFieldCreate'
      responses:
        '201':
          description: Custom field created
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CustomField'
      x-microcks-operation:
        delay: 0
        dispatcher: FALLBACK
  /CustomFields('{fieldId}'):
    get:
      operationId: getCustomField
      summary: Microsoft Project Get Custom Field
      description: Retrieve a specific custom field by ID.
      tags:
      - Custom Fields
      parameters:
      - $ref: '#/components/parameters/fieldId'
      responses:
        '200':
          description: Custom field details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CustomField'
      x-microcks-operation:
        delay: 0
        dispatcher: FALLBACK
    delete:
      operationId: deleteCustomField
      summary: Microsoft Project Delete Custom Field
      description: Delete a custom field definition.
      tags:
      - Custom Fields
      parameters:
      - $ref: '#/components/parameters/fieldId'
      responses:
        '204':
          description: Custom field deleted
      x-microcks-operation:
        delay: 0
        dispatcher: FALLBACK
components:
  schemas:
    CustomFieldCreate:
      type: object
      required:
      - Name
      - FieldType
      - EntityType
      properties:
        Name:
          type: string
          description: Custom field display name
        FieldType:
          type: integer
          description: Field data type
        EntityType:
          type: integer
          description: Entity type
        Description:
          type: string
          description: Field description
    CustomField:
      type: object
      properties:
        Id:
          type: string
          format: uuid
          description: Custom field identifier
        InternalName:
          type: string
          description: Internal name of the custom field
          example: Custom_x0020_Text1
        Name:
          type: string
          description: Display name of the custom field
          example: Department Code
        FieldType:
          type: integer
          description: Field data type (0=Cost, 1=Date, 2=Duration, 3=Finish, 4=Flag, 5=Number, 6=Start, 7=Text)
          example: 7
        EntityType:
          type: integer
          description: Entity type (0=Project, 1=Resource, 2=Task)
          example: 2
        Description:
          type: string
          description: Field description
          example: Custom field for department codes
        LookupTableId:
          type: string
          format: uuid
          description: Associated lookup table ID
        IsRequired:
          type: boolean
          description: Whether the field is required
          example: false
        IsMultilineText:
          type: boolean
          description: Whether the text field supports multiple lines
          example: false
        Formula:
          type: string
          description: Calculated field formula
    CustomFieldCollection:
      type: object
      properties:
        value:
          type: array
          items:
            $ref: '#/components/schemas/CustomField'
  parameters:
    fieldId:
      name: fieldId
      in: path
      required: true
      description: The GUID identifier of the custom field
      schema:
        type: string
        format: uuid
  securitySchemes:
    oauth2:
      type: oauth2
      description: OAuth 2.0 authentication via Azure AD for SharePoint Online
      flows:
        authorizationCode:
          authorizationUrl: https://login.microsoftonline.com/common/oauth2/authorize
          tokenUrl: https://login.microsoftonline.com/common/oauth2/token
          scopes:
            ProjectServer.Read: Read Project Server data
            ProjectServer.ReadWrite: Read and write Project Server data