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

# Sales Return Invoices

> Fields, numbering, warehouse movement and customer ledger rules of sales return invoices.

A sales return invoice has the same fields, lines and rules as a [purchase invoice](/en/v1/purchase-invoices/overview) — see that page for required fields, the customer snapshot, line rules, Lot/serial number tracking, line identity on update and sharing. This page only covers what is different for a sales return invoice.

| Operation      | Endpoint                                                                           |
| -------------- | ---------------------------------------------------------------------------------- |
| List           | [`GET /sales-return-invoices`](/en/v1/sales-return-invoices/list)                  |
| Get            | [`GET /sales-return-invoices/{invoiceId}`](/en/v1/sales-return-invoices/get)       |
| Create         | [`POST /sales-return-invoices`](/en/v1/sales-return-invoices/create)               |
| Update         | [`PUT /sales-return-invoices/{invoiceId}`](/en/v1/sales-return-invoices/update)    |
| Partial update | [`PATCH /sales-return-invoices/{invoiceId}`](/en/v1/sales-return-invoices/patch)   |
| Delete         | [`DELETE /sales-return-invoices/{invoiceId}`](/en/v1/sales-return-invoices/delete) |

## Numbering

Send `InvoiceNumber` as `"Next"` to generate it automatically from the **SATİADEFATNO** number series (this invoice type does not use the e-Invoice numbering). `"Next"` cannot be sent on update, and `InvoiceNumber` must be unique in the company among sales return invoices.

## Warehouse movement

Every line's [generated warehouse movement](/en/v1/purchase-invoices/overview#warehouse-movement-lot-and-serial-number-tracking) is **inbound** for a sales return invoice (the customer sends goods back, so stock increases), so `Lots`/`SerialNumbers` follow the inbound rules (each Lot entry creates a new lot, each serial number registers a new one).

<Info>
  No real sales return invoices exist yet in the data used to build this API, so the inbound direction of the generated warehouse movement is inferred from the inbound/outbound convention of the other invoice types, not directly verified. Report any discrepancy you find.
</Info>

## Customer ledger

A sales return invoice's [customer ledger entry](/en/v1/purchase-invoices/overview#customer-ledger) is a **credit** (it reverses the debit a sales invoice would have created). If it has already been closed by a payment, the invoice's customer, amount and currency can no longer be changed, and the invoice cannot be deleted (`3015`).