## List Keys

**post** `/v1/customFields/listKeys`

List all active custom field keys, optionally filtered by entity type.

### Returns

- **data:** `array of object`

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

  - **entity:** `"alert" OR "billable_metric" OR "charge" OR 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`

- **next\_page:** `string`