Create Field

Create a new contact field in your workspace.

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Endpoint

POST https://api.campaignlark.com/v1/fields

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Request Body

Field	Type	Required	Description
label	string	required	Human-readable display name. 1–32 characters. Must be unique within the workspace.
merge_tag	string	required	The key used to reference this field in contact data payloads. 2–16 characters, lowercase letters and underscores only. Must be unique.
type	string	required	Data type of the field. One of TEXT, NUMBER, BOOLEAN, DATE, DROPDOWN_SINGLE, DROPDOWN_MULTIPLE, COUNTRY.
definition	string	conditional	Required for DROPDOWN_SINGLE and DROPDOWN_MULTIPLE types. Comma-separated list of at least 2 unique options.
default_value	string	optional	Value used when no value is provided for this field.
required	boolean	optional	Whether this field must have a value on every contact. Defaults to false.

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Sample Request

POST https://api.campaignlark.com/v1/fields
Content-Type: application/json

{
  "label": "Favorite Color",
  "merge_tag": "fav_color",
  "type": "DROPDOWN_SINGLE",
  "definition": "Red,Blue,Green",
  "default_value": "",
  "required": false
}

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Response

Success — 201 Created

{
  "data": {
    "id": 6,
    "label": "Favorite Color",
    "merge_tag": "fav_color",
    "type": "DROPDOWN_SINGLE",
    "definition": "Red,Blue,Green",
    "default_value": "",
    "order": 60,
    "immutable": false,
    "required": false
  }
}

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Errors

Status	Message	Cause
400	Validation error	label is missing, empty, or exceeds 32 characters.
400	Validation error	merge_tag is missing, invalid format, or exceeds 16 characters.
400	Validation error	type is missing or not one of the valid field types.
400	Validation error	definition is required for dropdown types and must contain at least 2 unique options.
400	Validation error	A field with the same label or merge_tag already exists.
400	Validation error	Cannot create immutable fields via the API.
400	Validation error	An import or export is currently in progress.