Create and list custom contact fields (schema metadata).
openapi: 3.1.0
info:
description: '## Overview
An API specification to provide a Custom Sync Location in Knak.
By implementing a service conforming to this API specification, you will be able to send asset data to your own service and have that service specify a sync location based on that data.
## Authentication
Knak provides two options for authentication:
- **Basic Authentication**: Knak will use Basic Authentication to authenticate with your API. You will just need to provide a username and password when configuring the integration.
- **OAuth2**: Knak will use OAuth2 to authenticate with your API. You will need to implement endpoints under a specified authorization path to support this. The default path will be `/oauth/token` but you can provide a separate path when configuring the integration if you so choose. The flow used is the standard [Authorization Code Grant](https://tools.ietf.org/html/rfc6749#section-4.1).
Knak will use the tokens generated to make requests from your service.
## Custom Sync Location
When a user has a custom sync location configured and they have set up a sync restriction that leverages the custom sync location.
Knak will call the `/knak-sync-location` (or your own specified path) endpoint with the asset data when an asset is synced. Your service should return a response with the sync location for the asset.
When your service provides a sync location, Knak will use that location to display only the available sync location to the user.
'
version: V1
title: Custom Sync Location API Reference Asset Custom Fieldsets Fields API
x-logo:
url: https://s3.amazonaws.com/assets.knak.io/img/Knak-Logo-Medium.png
servers:
- url: https://yourService.com/your-sync-location-api
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:
responses:
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
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.
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:
PageNumber:
name: page[number]
in: query
required: false
description: The page of results to return (1-based).
schema:
type: integer
minimum: 1
default: 1
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
schemas:
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.
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'
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.
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.
FieldType:
type: string
description: The data type of a field.
enum:
- string
- number
- date
- datetime
- boolean