Knak Fields API

openapi: 3.2.0
info:
  title: Knak Send Contacts API Reference Fields API
  version: V1
  x-logo:
    url: https://s3.amazonaws.com/assets.knak.io/img/Knak-Logo-Medium.png
  contact:
    email: support@knak.com
  description: '# Overview

    Welcome to the developer documentation for the Knak Send API.'
servers:
- url: https://send.knak.io/api/public/v1
  description: production
security:
- bearerAuth: []
tags:
- name: Fields
  description: Create and list custom contact fields (schema metadata).
paths:
  /fields:
    get:
      tags:
      - Fields
      summary: List fields
      description: 'Returns all custom contact fields for the authenticated company. Fields are schema metadata sourced

        from connected systems and created via this API; the list is not paginated.'
      operationId: listFields
      responses:
        '200':
          description: The list of fields.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/Field'
              examples:
                default:
                  value:
                    data:
                    - id: f1e2d3c4-b5a6-7890-abcd-ef1234567890
                      key: department
                      name: Department
                      type: string
                      directory_id: d4c3b2a1-0f9e-8765-abcd-ef1234567890
        '401':
          $ref: '#/components/responses/Unauthenticated'
        '403':
          $ref: '#/components/responses/Forbidden'
        '429':
          $ref: '#/components/responses/TooManyRequests'
    post:
      tags:
      - Fields
      summary: Create a field
      description: 'Creates a new custom contact field. The field''s `key` is generated automatically from its `name`

        (for example `Start Date` becomes `startDate`). Attempting to create a field whose generated key

        already exists returns a `409 Conflict`.'
      operationId: createField
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/FieldInput'
            examples:
              default:
                value:
                  name: Department
                  type: string
      responses:
        '201':
          description: The field was created.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    $ref: '#/components/schemas/Field'
        '401':
          $ref: '#/components/responses/Unauthenticated'
        '403':
          $ref: '#/components/responses/Forbidden'
        '409':
          $ref: '#/components/responses/FieldConflict'
        '422':
          $ref: '#/components/responses/ValidationError'
        '429':
          $ref: '#/components/responses/TooManyRequests'
  /fields/{id}/values:
    get:
      tags:
      - Fields
      summary: List a field's values
      description: 'Returns the distinct values stored for a single field across the company''s contacts. Results are

        paginated and sorted alphabetically by value by default.'
      operationId: listFieldValues
      parameters:
      - $ref: '#/components/parameters/FieldId'
      - $ref: '#/components/parameters/PageNumber'
      - $ref: '#/components/parameters/PageSize'
      - name: sort[]
        in: query
        required: false
        description: Sort by value, passed as a repeated `sort[]` parameter. Prefix with `-` for descending order. Defaults to ascending by value.
        style: form
        explode: true
        schema:
          type: array
          items:
            type: string
            enum:
            - value
            - -value
        example:
        - value
      responses:
        '200':
          description: A paginated list of the field's distinct values.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      type: string
                  meta:
                    $ref: '#/components/schemas/PaginationMeta'
              examples:
                default:
                  value:
                    data:
                    - Engineering
                    - Marketing
                    - Sales
                    meta:
                      total: 3
                      current_page: 1
                      last_page: 1
                      per_page: 25
                      from: 1
                      to: 3
        '401':
          $ref: '#/components/responses/Unauthenticated'
        '403':
          $ref: '#/components/responses/Forbidden'
        '404':
          $ref: '#/components/responses/FieldNotFound'
        '422':
          $ref: '#/components/responses/ValidationError'
        '429':
          $ref: '#/components/responses/TooManyRequests'
components:
  schemas:
    ErrorObject:
      type: object
      description: The compact error shape returned for authentication, authorization and conflict errors.
      properties:
        error:
          type: object
          properties:
            code:
              type: string
              description: A machine-readable error code.
            message:
              type: string
              description: A human-readable description of the error.
    FieldType:
      type: string
      description: The data type of a field.
      enum:
      - string
      - number
      - date
      - datetime
      - boolean
    Field:
      type: object
      description: A custom contact field (schema metadata).
      properties:
        id:
          type: string
          description: The unique identifier of the field.
        key:
          type: string
          description: The generated key of the field, derived from its name (for example `startDate`).
        name:
          type: string
          description: The human-readable name of the field.
        type:
          $ref: '#/components/schemas/FieldType'
        directory_id:
          type: string
          description: The ID of the directory the field belongs to.
    HttpError:
      type: object
      description: The error shape returned for rate-limit (429) errors.
      properties:
        message:
          type: string
          description: A human-readable description of the error.
        type:
          type: string
          description: The error type. Always `HttpException` for this shape.
    FieldInput:
      type: object
      description: The payload used to create a field.
      required:
      - name
      - type
      properties:
        name:
          type: string
          maxLength: 255
          description: The human-readable name of the field. The field key is generated from this value.
        type:
          $ref: '#/components/schemas/FieldType'
    PaginationMeta:
      type: object
      description: Pagination metadata describing the current result window.
      properties:
        total:
          type: integer
          description: The total number of matching records.
        current_page:
          type: integer
        last_page:
          type: integer
        per_page:
          type: integer
        from:
          type:
          - integer
          - 'null'
          description: The index of the first record on the current page.
        to:
          type:
          - integer
          - 'null'
          description: The index of the last record on the current page.
    ErrorList:
      type: object
      description: The error shape returned for validation and not-found errors.
      properties:
        error_at:
          type: string
          format: date-time
          description: ISO 8601 timestamp of when the error occurred.
        errors:
          type: array
          items:
            type: object
            properties:
              identifier:
                type: string
                description: A machine-readable identifier for the error type.
              details:
                type: string
                description: A human-readable description of the error.
              meta:
                type: object
                description: Additional context. For validation errors, a map of field name to validation messages.
  responses:
    ValidationError:
      description: One or more request fields failed backend validation.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorList'
          example:
            error_at: '2026-06-02T13:56:31+00:00'
            errors:
            - identifier: ValidationError
              details: One or more of the given request fields failed backend validation.
              meta:
                email:
                - The email field is required.
    Forbidden:
      description: Knak Send access is not enabled for the account, or the token lacks the required scope.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorObject'
          example:
            error:
              code: ACCESS_DENIED
              message: Knak Send access is not enabled for this account.
    TooManyRequests:
      description: 'The rate limit for the endpoint has been exceeded. A `Retry-After` header indicates how many seconds

        to wait before retrying.

        '
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/HttpError'
          example:
            message: Too Many Attempts.
            type: HttpException
    FieldConflict:
      description: A field with the same generated key already exists.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorObject'
          example:
            error:
              code: FIELD_ALREADY_EXISTS
              message: A field with the name Department already exists in API directory.
    Unauthenticated:
      description: The access token is missing, invalid or expired.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorObject'
          example:
            error:
              code: UNAUTHENTICATED
              message: Invalid or expired access token.
    FieldNotFound:
      description: No field exists with the given ID.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorObject'
          example:
            error:
              code: FIELD_NOT_FOUND
              message: Field with id f1e2d3c4-b5a6-7890-abcd-ef1234567890 not found.
  parameters:
    PageSize:
      name: page[size]
      in: query
      required: false
      description: The number of records per page.
      schema:
        type: integer
        minimum: 1
        maximum: 100
        default: 25
    FieldId:
      name: id
      in: path
      required: true
      description: The unique identifier of the field.
      schema:
        type: string
      example: f1e2d3c4-b5a6-7890-abcd-ef1234567890
    PageNumber:
      name: page[number]
      in: query
      required: false
      description: The page of results to return (1-based).
      schema:
        type: integer
        minimum: 1
        default: 1
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: A bearer token generated through the Enterprise API Access menu.
x-provenance:
  method: harvested
  publisher: Knak
  source: https://developer.knak.com/openapi/send/send-api.yml
  note: split by refine-openapis from the provider's own published document, verified by fetch (openapi/_original/*.fetch.json);
    stamped by stamp-openapi-provenance.py (roadmap#793)