# Supplemental Documents
> Supplemental Documents are uploaded files connected to an Entity during onboarding.

## The Supplemental Document object
### Example
```json
{
  "created_at": "2020-01-31T23:59:59Z",
  "entity_id": "entity_n8y8tnk2p9339ti393yi",
  "file_id": "file_makxrc67oh9l6sg7w9yc",
  "idempotency_key": null,
  "type": "entity_supplemental_document"
}
```
### Attributes
- `created_at` (string)
  The [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) time at which the Supplemental Document was created.

- `entity_id` (string)
  The Entity the supplemental document is attached to.

- `file_id` (string)
  The File containing the document.

- `idempotency_key` (string, nullable)
  The idempotency key you chose for this object. This value is unique across Increase and is used to ensure that a request is only processed once. Learn more about [idempotency](https://increase.com/documentation/idempotency-keys).

- `type` (string)
  A constant representing the object's type. For this resource it will always be `entity_supplemental_document`.

## List Entity Supplemental Document Submissions
GET /entity_supplemental_documents

### Example
```curl
curl \
  --url "${INCREASE_URL}/entity_supplemental_documents?entity_id=entity_n8y8tnk2p9339ti393yi" \
  -H "Authorization: Bearer ${INCREASE_API_KEY}"
```

### Query Parameters
- `cursor` (string, optional)
  Return the page of entries after this one.

- `limit` (integer, optional)
  Limit the size of the list that is returned. The default (and maximum) is 100 objects.

- `entity_id` (string, required)
  The identifier of the Entity to list supplemental documents for.

- `idempotency_key` (string, optional)
  Filter records to the one with the specified `idempotency_key` you chose for that object. This value is unique across Increase and is used to ensure that a request is only processed once. Learn more about [idempotency](https://increase.com/documentation/idempotency-keys).

### Returns a Supplemental Document List object:
```json
{
  "data": [
    {
      "created_at": "2020-01-31T23:59:59Z",
      "entity_id": "entity_n8y8tnk2p9339ti393yi",
      "file_id": "file_makxrc67oh9l6sg7w9yc",
      "idempotency_key": null,
      "type": "entity_supplemental_document"
    }
  ],
  "next_cursor": "v57w5d"
}
```

## Create a supplemental document for an Entity
POST /entity_supplemental_documents

### Example
```curl
curl -X "POST" \
  --url "${INCREASE_URL}/entity_supplemental_documents" \
  -H "Authorization: Bearer ${INCREASE_API_KEY}" \
  -H "Content-Type: application/json" \
  -d $'{
    "entity_id": "entity_n8y8tnk2p9339ti393yi",
    "file_id": "file_makxrc67oh9l6sg7w9yc"
  }'
```

### Body Parameters
- `entity_id` (string, required)
  The identifier of the Entity to associate with the supplemental document.

- `file_id` (string, required)
  The identifier of the File containing the document.