# Custom Fields

The [Custom Fields](https://mavenlink.zendesk.com/hc/en-us/articles/202924760-Custom-Fields-Overview-#arrange) object allows you to
view, create, update, and delete extra fields for additional Estimate, Project, Group, Resource, Task, and User information.
If Custom Fields represent the fields themselves, [Custom Field Values](/tag/Custom-Field-Values)
represent the values in/of those fields.

 - [GET /custom_fields](https://developer.kantata.com/kantata/specification/custom-fields/get%20custom%20fields.md): Returns all Custom Fields, unless filter parameters have been applied. This endpoint returns structured Custom Field objects. As with all Kantata OX API endpoints, the returned data will be referenced
 - [POST /custom_fields](https://developer.kantata.com/kantata/specification/custom-fields/create%20custom%20field.md): This endpoint returns structured Custom Field objects. As with all Kantata OX API endpoints, the returned data will be referenced in sorted order in the `results` array and will be indexed by ID in th
 - [PUT /custom_fields/{id}](https://developer.kantata.com/kantata/specification/custom-fields/update%20custom%20field.md): Updates an existing custom field. ### Parameters that cannot be updated Note that the `unique_constraint` and `value_type` parameters cannot be updated. They are set during the process of [creating a
 - [DELETE /custom_fields/{id}](https://developer.kantata.com/kantata/specification/custom-fields/delete%20custom%20field.md): Deletes a custom field. Custom field values are deleted with their custom fields. The response will contain no content and an HTTP 204 status code if the request was successful, or a [standard Kantata