# Order Line Item
Represents a line item in an order. Each line item describes a different
product to purchase, with its own quantity and price details.
## Structure
`OrderLineItem`
## Fields
| Name | Type | Tags | Description |
| --- | --- | --- | --- |
| `uid` | `string \| null \| undefined` | Optional | A unique ID that identifies the line item only within this order.
**Constraints**: *Maximum Length*: `60` |
| `name` | `string \| null \| undefined` | Optional | The name of the line item.
**Constraints**: *Maximum Length*: `512` |
| `quantity` | `string` | Required | The count, or measurement, of a line item being purchased:
If `quantity` is a whole number, and `quantity_unit` is not specified, then `quantity` denotes an item count. For example: `3` apples.
If `quantity` is a whole or decimal number, and `quantity_unit` is also specified, then `quantity` denotes a measurement. For example: `2.25` pounds of broccoli.
For more information, see [Specify item quantity and measurement unit](https://developer.squareup.com/docs/orders-api/create-orders#specify-item-quantity-and-measurement-unit).
Line items with a quantity of `0` are automatically removed
when paying for or otherwise completing the order.
**Constraints**: *Minimum Length*: `1`, *Maximum Length*: `12` |
| `quantityUnit` | [`OrderQuantityUnit \| undefined`](../../doc/models/order-quantity-unit.md) | Optional | Contains the measurement unit for a quantity and a precision that
specifies the number of digits after the decimal point for decimal quantities. |
| `note` | `string \| null \| undefined` | Optional | An optional note associated with the line item.
**Constraints**: *Maximum Length*: `2000` |
| `catalogObjectId` | `string \| null \| undefined` | Optional | The [CatalogItemVariation](entity:CatalogItemVariation) ID applied to this line item.
**Constraints**: *Maximum Length*: `192` |
| `catalogVersion` | `bigint \| null \| undefined` | Optional | The version of the catalog object that this line item references. |
| `variationName` | `string \| null \| undefined` | Optional | The name of the variation applied to this line item.
**Constraints**: *Maximum Length*: `400` |
| `itemType` | [`string \| undefined`](../../doc/models/order-line-item-item-type.md) | Optional | Represents the line item type. |
| `metadata` | `Record \| null \| undefined` | Optional | Application-defined data attached to this line item. Metadata fields are intended
to store descriptive references or associations with an entity in another system or store brief
information about the object. Square does not process this field; it only stores and returns it
in relevant API calls. Do not use metadata to store any sensitive information (such as personally
identifiable information or card details).
Keys written by applications must be 60 characters or less and must be in the character set
`[a-zA-Z0-9_-]`. Entries can also include metadata generated by Square. These keys are prefixed
with a namespace, separated from the key with a ':' character.
Values have a maximum length of 255 characters.
An application can have up to 10 entries per metadata field.
Entries written by applications are private and can only be read or modified by the same
application.
For more information, see [Metadata](https://developer.squareup.com/docs/build-basics/metadata). |
| `modifiers` | [`OrderLineItemModifier[] \| null \| undefined`](../../doc/models/order-line-item-modifier.md) | Optional | The [CatalogModifier](entity:CatalogModifier)s applied to this line item. |
| `appliedTaxes` | [`OrderLineItemAppliedTax[] \| null \| undefined`](../../doc/models/order-line-item-applied-tax.md) | Optional | The list of references to taxes applied to this line item. Each
`OrderLineItemAppliedTax` has a `tax_uid` that references the `uid` of a
top-level `OrderLineItemTax` applied to the line item. On reads, the
amount applied is populated.
An `OrderLineItemAppliedTax` is automatically created on every line
item for all `ORDER` scoped taxes added to the order. `OrderLineItemAppliedTax`
records for `LINE_ITEM` scoped taxes must be added in requests for the tax
to apply to any line items.
To change the amount of a tax, modify the referenced top-level tax. |
| `appliedDiscounts` | [`OrderLineItemAppliedDiscount[] \| null \| undefined`](../../doc/models/order-line-item-applied-discount.md) | Optional | The list of references to discounts applied to this line item. Each
`OrderLineItemAppliedDiscount` has a `discount_uid` that references the `uid` of a top-level
`OrderLineItemDiscounts` applied to the line item. On reads, the amount
applied is populated.
An `OrderLineItemAppliedDiscount` is automatically created on every line item for all
`ORDER` scoped discounts that are added to the order. `OrderLineItemAppliedDiscount` records
for `LINE_ITEM` scoped discounts must be added in requests for the discount to apply to any
line items.
To change the amount of a discount, modify the referenced top-level discount. |
| `appliedServiceCharges` | [`OrderLineItemAppliedServiceCharge[] \| null \| undefined`](../../doc/models/order-line-item-applied-service-charge.md) | Optional | The list of references to service charges applied to this line item. Each
`OrderLineItemAppliedServiceCharge` has a `service_charge_id` that references the `uid` of a
top-level `OrderServiceCharge` applied to the line item. On reads, the amount applied is
populated.
To change the amount of a service charge, modify the referenced top-level service charge. |
| `basePriceMoney` | [`Money \| undefined`](../../doc/models/money.md) | Optional | Represents an amount of money. `Money` fields can be signed or unsigned.
Fields that do not explicitly define whether they are signed or unsigned are
considered unsigned and can only hold positive amounts. For signed fields, the
sign of the value indicates the purpose of the money transfer. See
[Working with Monetary Amounts](https://developer.squareup.com/docs/build-basics/working-with-monetary-amounts)
for more information. |
| `variationTotalPriceMoney` | [`Money \| undefined`](../../doc/models/money.md) | Optional | Represents an amount of money. `Money` fields can be signed or unsigned.
Fields that do not explicitly define whether they are signed or unsigned are
considered unsigned and can only hold positive amounts. For signed fields, the
sign of the value indicates the purpose of the money transfer. See
[Working with Monetary Amounts](https://developer.squareup.com/docs/build-basics/working-with-monetary-amounts)
for more information. |
| `grossSalesMoney` | [`Money \| undefined`](../../doc/models/money.md) | Optional | Represents an amount of money. `Money` fields can be signed or unsigned.
Fields that do not explicitly define whether they are signed or unsigned are
considered unsigned and can only hold positive amounts. For signed fields, the
sign of the value indicates the purpose of the money transfer. See
[Working with Monetary Amounts](https://developer.squareup.com/docs/build-basics/working-with-monetary-amounts)
for more information. |
| `totalTaxMoney` | [`Money \| undefined`](../../doc/models/money.md) | Optional | Represents an amount of money. `Money` fields can be signed or unsigned.
Fields that do not explicitly define whether they are signed or unsigned are
considered unsigned and can only hold positive amounts. For signed fields, the
sign of the value indicates the purpose of the money transfer. See
[Working with Monetary Amounts](https://developer.squareup.com/docs/build-basics/working-with-monetary-amounts)
for more information. |
| `totalDiscountMoney` | [`Money \| undefined`](../../doc/models/money.md) | Optional | Represents an amount of money. `Money` fields can be signed or unsigned.
Fields that do not explicitly define whether they are signed or unsigned are
considered unsigned and can only hold positive amounts. For signed fields, the
sign of the value indicates the purpose of the money transfer. See
[Working with Monetary Amounts](https://developer.squareup.com/docs/build-basics/working-with-monetary-amounts)
for more information. |
| `totalMoney` | [`Money \| undefined`](../../doc/models/money.md) | Optional | Represents an amount of money. `Money` fields can be signed or unsigned.
Fields that do not explicitly define whether they are signed or unsigned are
considered unsigned and can only hold positive amounts. For signed fields, the
sign of the value indicates the purpose of the money transfer. See
[Working with Monetary Amounts](https://developer.squareup.com/docs/build-basics/working-with-monetary-amounts)
for more information. |
| `pricingBlocklists` | [`OrderLineItemPricingBlocklists \| undefined`](../../doc/models/order-line-item-pricing-blocklists.md) | Optional | Describes pricing adjustments that are blocked from automatic
application to a line item. For more information, see
[Apply Taxes and Discounts](https://developer.squareup.com/docs/orders-api/apply-taxes-and-discounts). |
| `totalServiceChargeMoney` | [`Money \| undefined`](../../doc/models/money.md) | Optional | Represents an amount of money. `Money` fields can be signed or unsigned.
Fields that do not explicitly define whether they are signed or unsigned are
considered unsigned and can only hold positive amounts. For signed fields, the
sign of the value indicates the purpose of the money transfer. See
[Working with Monetary Amounts](https://developer.squareup.com/docs/build-basics/working-with-monetary-amounts)
for more information. |
## Example (as JSON)
```json
{
"uid": "uid4",
"name": "name4",
"quantity": "quantity0",
"quantity_unit": {
"measurement_unit": {
"custom_unit": {
"name": "name2",
"abbreviation": "abbreviation4"
},
"area_unit": "IMPERIAL_ACRE",
"length_unit": "IMPERIAL_INCH",
"volume_unit": "METRIC_LITER",
"weight_unit": "IMPERIAL_WEIGHT_OUNCE"
},
"precision": 54,
"catalog_object_id": "catalog_object_id0",
"catalog_version": 12
},
"note": "note0",
"catalog_object_id": "catalog_object_id8"
}
```