## Add Key

`client.v1.customFields.addKey(CustomFieldAddKeyParamsbody, RequestOptionsoptions?): void`

**post** `/v1/customFields/addKey`

Add a key to the allow list for a given entity. There is a 100 character limit on custom field keys.

### Parameters

- **body:** `CustomFieldAddKeyParams`

  - **enforce\_uniqueness:** `boolean`

  - **entity:** `"alert" | "billable_metric" | "charge" | 15 more`

    - `"alert"`

    - `"billable_metric"`

    - `"charge"`

    - `"commit"`

    - `"contract_credit"`

    - `"contract_product"`

    - `"contract"`

    - `"credit_grant"`

    - `"customer_plan"`

    - `"customer"`

    - `"discount"`

    - `"invoice"`

    - `"plan"`

    - `"professional_service"`

    - `"product"`

    - `"rate_card"`

    - `"scheduled_charge"`

    - `"subscription"`

  - **key:** `string`

### Example

```node
import Metronome from '@metronome/sdk';

const client = new Metronome({
  bearerToken: 'My Bearer Token',
});

await client.v1.customFields.addKey({ enforce_uniqueness: true, entity: 'customer', key: 'x_account_id' });
```