---
title: "Mark Invoice as unpaid"
method: POST
path: "/sales/markUnpaid"
tags: ["Sales"]
---

# Mark Invoice as unpaid

`POST /sales/markUnpaid`

## Request

- Base URL: `https://api.altera.co`
- URL: `https://api.altera.co/sales/markUnpaid`
- Auth: API key in header `Authorization`

Sets the payment status of selected invoices as unpaid, sets paidAmount to 0.

## Request body

- object
  - `invoiceIds` integer[]

## Response `200`

OK

- SuccessResponse: Regular format of success response in Altera API Retrieved information will always be stored in the 'data' node
  - `result` 'OK'
  - `data` object

## Other responses

- `401`: KEY_EXPIRED: a verified API key has expired. This requires that the company still has OpenAPI access. Unknown/invalid keys can receive the gateway 403.

## Changes

- **2026-10-12** `45544bcb4e8a`: 1 info
  - added the non-success response with the status `401`
- **2024-08-26** `64c683372c45`: 1 info
  - endpoint added
- **2024-08-26** `a2d864f3a8db`: 1 breaking
  - api path removed without deprecation

[Operation history](https://skmtc.dev/altera-co/apis/altera-api/changes/sales/markUnpaid/post.md)

---

[API](https://skmtc.dev/altera-co/apis/altera-api.md) - [All operations](https://skmtc.dev/altera-co/apis/altera-api/llms.txt) - [OpenAPI document](https://skmtc.dev/altera-co/apis/altera-api/revisions/45544bcb4e8a?raw)