# Create an item attribute

Operation ID: `createItemAttributeDefinition`

Group: Inventory › Item Attribute Definitions

[Open in the interactive reference](https://docs.api.lensing.ai/lensing/v1/endpoints/createItemAttributeDefinition)

`POST /inventory/item-attribute-definitions`

Retry-safe: A write that accepts Idempotency-Key: repeating a request with the same key replays the stored answer instead of executing twice.

Creates an item attribute and, in the same request, the values it allows. The attribute's name is unique within the tenant: a name already in use fails with DUPLICATE_NAME. valueType is TEXT or NUMBER and defaults to TEXT; under NUMBER every value must parse as a number, so 'Red' fails with NON_NUMERIC_VALUE rather than being stored as a value nothing can read. This is the only route on item attribute definitions: there is no read, update or delete, so an attribute created here is afterward maintained through the Item Attributes screen or a CSV upload.

## Parameters

| Name | In | Type | Required | Description |
| --- | --- | --- | --- | --- |
| `Api-Version` | header | string · v1 | yes | The API version this request targets, named by its public identifier. Required on every request; omitting it, or naming a version this company does not have, is answered with 400. This document describes version `v1`. |
| `Idempotency-Key` | header | string | no | An opaque caller-chosen string (1-255 characters) that makes this request safe to retry. Repeating the same key with an identical request body replays the original response instead of re-executing - but only once that original request succeeded; a failed attempt re-executes on retry. Repeating the key with a different body is answered with 422. A key still in flight is answered with 409 - as is a key whose original request was interrupted before it finished, for a few minutes afterwards, until that attempt is presumed dead. A completed response stays replayable for 24 hours. The key is scoped to the caller, not to the action: reusing it for a different action is answered with 409 or 422 rather than treated independently. On read actions this header is ignored. On write actions that cannot offer the guarantee it is answered with `400 IDEMPOTENCY_NOT_SUPPORTED` rather than silently ignored. |

## Request body

Required, `application/json`: createItemAttributeDefinitionInput.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `name` | string | yes | The attribute's name, for example 'Colour'. Unique within the tenant. Example: `"Colour"`. |
| `description` | string | no | What the attribute is for. Free text, shown beside it in the UI. Example: `"Product colour"`. |
| `valueType` | string | no | TEXT or NUMBER. Defaults to TEXT. Under NUMBER every value must parse as a number. Example: `"TEXT"`. |
| `values` | array<string> | no | The values this attribute allows, for example ['Red','Green']. May be omitted to create the attribute with no values yet; there is no update route, so further values are added through the Item Attributes screen or a CSV upload. Example: `["Red","Green","Blue"]`. |

```json
{
  "name": "Colour",
  "description": "Product colour",
  "valueType": "TEXT",
  "values": [
    "Red",
    "Green",
    "Blue"
  ]
}
```

## Response

`200` Success

Under `data` (createItemAttributeDefinitionOutput):

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `id` | string | yes | The unique identifier for the new attribute. Example: `"c7a84f92-1e63-4d55-b0a1-6f7e3b9c2d48"`. |
| `name` | string | yes | The attribute's name. Example: `"Colour"`. |
| `description` | string | no | What the attribute is for. Example: `"Product colour"`. |
| `valueType` | string | no | TEXT or NUMBER. Example: `"TEXT"`. |
| `values` | array<object> | yes | The values this attribute allows, each with its own identifier. Example: `[{"id":"2b6d0e14-8f77-4a91-95c3-1d4e8a7f6b03","value":"Red"},{"id":"8e1a5c39-4b62-4d17-9f08-3a7c21d5e690","value":"Green"},{"id":"5d92f7b1-6c04-4e83-a215-9b83f4e07c2d","value":"Blue"}]`. |
| `values[].id` | string | yes |  |
| `values[].value` | string | yes |  |

```json
{
  "data": {
    "id": "c7a84f92-1e63-4d55-b0a1-6f7e3b9c2d48",
    "name": "Colour",
    "description": "Product colour",
    "valueType": "TEXT",
    "values": [
      {
        "id": "2b6d0e14-8f77-4a91-95c3-1d4e8a7f6b03",
        "value": "Red"
      },
      {
        "id": "8e1a5c39-4b62-4d17-9f08-3a7c21d5e690",
        "value": "Green"
      },
      {
        "id": "5d92f7b1-6c04-4e83-a215-9b83f4e07c2d",
        "value": "Blue"
      }
    ]
  },
  "diagnostics": [
    {
      "code": "<code>",
      "message": "<message>",
      "severity": "error",
      "path": [
        "<path>"
      ],
      "details": "<details>"
    }
  ]
}
```

## Response headers

- `Idempotency-Replayed` — Present and `true` only when this response replays a previously stored one for the same Idempotency-Key, rather than reflecting a live execution. Absent on a live response - never sent as `false`.

## Errors

| Code | Status |
| --- | --- |
| `DUPLICATE_NAME` | 400 |
| `UNKNOWN_VALUE_TYPE` | 400 |
| `NON_NUMERIC_VALUE` | 400 |
| `IDEMPOTENCY_KEY_CONFLICT` | 409 |
| `IDEMPOTENCY_PAYLOAD_MISMATCH` | 422 |

## Statuses

- `400` — Invalid request or business failure. Codes: DUPLICATE_NAME, UNKNOWN_VALUE_TYPE, NON_NUMERIC_VALUE
- `401` — The request carries no valid access token.
- `403` — Not authorized
- `404` — Not found
- `409` — The Idempotency-Key is still being processed by another request.
- `422` — The Idempotency-Key was already used with a different request payload.
- `429` — Too many requests from this client address. The response has no body and no `Retry-After` header.
- `500` — Internal server error