> ## 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.

# Bank Opening Vouchers

> Fields and exchange rate rules for the voucher that records a bank account's opening balance.

A bank opening voucher records the opening balance of one or more bank accounts. Unlike a bank transfer voucher, it **produces no customer movement**; only bank movement lines are written.

| Operation      | Endpoint                                                                               |
| -------------- | -------------------------------------------------------------------------------------- |
| List           | [`GET /finance/bank-openings`](/en/v1/finance/bank-openings/list)                      |
| Get            | [`GET /finance/bank-openings/{bankOpeningId}`](/en/v1/finance/bank-openings/get)       |
| Create         | [`POST /finance/bank-openings`](/en/v1/finance/bank-openings/create)                   |
| Update         | [`PUT /finance/bank-openings/{bankOpeningId}`](/en/v1/finance/bank-openings/update)    |
| Partial update | [`PATCH /finance/bank-openings/{bankOpeningId}`](/en/v1/finance/bank-openings/patch)   |
| Delete         | [`DELETE /finance/bank-openings/{bankOpeningId}`](/en/v1/finance/bank-openings/delete) |

## Required fields

* `VoucherNumber`: unique in the company **across all bank voucher types** (not only openings), at most 20 characters. Send `"Next"` to generate it from the same `"BANKAFİŞNO"` series used by [bank transfers](/en/v1/finance/bank-transfers/overview). Cannot be `"Next"` on update.
* `Date`: voucher date. If a time is sent it is stored as the voucher time, otherwise the current time is used.
* `Lines`: at least one line.

`Description` and `SharingCode` are optional; an empty `SharingCode` makes the voucher visible to everyone, otherwise it must be one of the user's [sharing codes](/en/v1/guides/sharing-codes).

## Lines

Unlike a bank transfer, **each line picks its own bank account** (the lines of a voucher are not all recorded against the same account):

* `BankAccountCode`: required, one of the company's [bank accounts](/en/v1/finance/bank-accounts/list). The line's currency is that account's own currency.
* `Debit`/`Credit`: exactly one must be greater than 0, the other must be `0` (send `Debit` to debit the account, for example).
* `ExchangeRate`: required (and must be greater than 0) when the bank account's currency **differs** from the company's default currency; otherwise treated as `1` even if not sent.
* `Description`: optional, per-line description.

The voucher's `ExchangeRate` (in the response) is the amount-weighted average of the lines — the same formula as [bank transfers](/en/v1/finance/bank-transfers/overview), where a line's amount is `Debit + Credit`.

<Info>
  Unlike a bank internal transfer, a bank opening voucher's lines do **not** need their total `Debit` to equal their total `Credit`.
</Info>

## Update

Since it produces no customer movement (there is no closed-record/payment-plan lock to worry about), lines are **fully replaced** on update: existing lines are removed and the lines in the request are saved.

## Posted voucher

When `IsPosted` is `true` (the voucher has been linked to an accounting entry) it **cannot be updated or deleted** (`8306`).