> ## Documentation Index
> Fetch the complete documentation index at: https://docs.trackstarhq.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Invoice Line Items

Invoice Line Items represent **individual charges** on a carrier invoice. Each line item is one charge — not one shipment and not one invoice. A single shipment typically produces multiple line items (for example, a base freight charge, a fuel surcharge, and a residential delivery surcharge would be three separate line items).

Invoice formats vary by carrier — UPS, FedEx, USPS, DHL, DPD, and Royal Mail each structure their invoices differently, and some carriers' shapes vary further by billing region. Trackstar parses each carrier's native format into a unified line-item schema described below. For concrete CSV shapes per integration, see [Carrier Sample Files](/api-reference/carrier-api/sample-files/overview).

### Fields

| Field                | Description                                   |
| :------------------- | :-------------------------------------------- |
| `id`                 | Unique identifier for the invoice line item   |
| `transaction_date`   | Date the charge was incurred                  |
| `account_id`         | Carrier account ID associated with the charge |
| `invoice_id`         | Invoice ID from the carrier                   |
| `gross_cost`         | Gross cost before discounts                   |
| `net_cost`           | Net cost after discounts                      |
| `charge_description` | Description of the charge type                |