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

# Glossary

> Clarifying commonly confused Bolta API terms such as supplier and supplied party.

Every tax invoice has a sending side and a receiving side. Mixing up the two parties means the invoice is issued to the wrong business, so it helps to align on the terms before you make a call.

## The two parties

| Term                           | Meaning                                                | Where it appears in the API                                                                    |
| ------------------------------ | ------------------------------------------------------ | ---------------------------------------------------------------------------------------------- |
| **Supplier (issuer)**          | The side that **issues** the tax invoice. The seller.  | `Supplier-Key` header, `POST /v1/suppliers` (register supplier), `supplierKey` in the response |
| **Supplied party (recipient)** | The side that **receives** the tax invoice. The buyer. | `supplied` field in the request body                                                           |

<Warning>
  **`Supplier-Key` is the key of the sending side (supplier), not the receiving side.**

  `Supplier-Key` takes the `supplierKey` of the **supplier itself** that issues the tax invoice. The receiving side (supplied party) information goes in the `supplied` field of the request body. Swapping the two values issues the invoice to a different business than intended.
</Warning>

## Who is the supplier?

The Bolta API is typically used in a model where a platform issues tax invoices on behalf of its own members - as with delegated issuance or reverse issuance. In this model, the entity that actually issues the tax invoice is the **supplier**. The platform first registers the supplier via the [Register Supplier API](/api-reference/supplier/register-supplier), then issues invoices by putting the returned `supplierKey` into the `Supplier-Key` header.

## Different from "customer" in the web service

The "customer" referred to in the \[Customer Management] menu of the Bolta web service is the counterparty - that is, the supplied party that **receives** the tax invoice. By contrast, the **supplier** identified by the key in the API is the side that **sends** the tax invoice. The parties they point to are opposite, so take care when using the web service and the API together.

| Context                                                     | Party referred to                          |
| ----------------------------------------------------------- | ------------------------------------------ |
| "Customer" in the web service \[Customer Management]        | Supplied party (recipient, receiving side) |
| Supplier in the Bolta API (`Supplier-Key`, `/v1/suppliers`) | Supplier (issuer, sending side)            |

## Cash receipt terms

The cash receipt API uses the following terms. As with tax invoices, `Supplier-Key` identifies the issuer.

| Term                                            | Meaning                                                                                                  | Where it appears in the API                               |
| ----------------------------------------------- | -------------------------------------------------------------------------------------------------------- | --------------------------------------------------------- |
| **Supplier (issuer)**                           | The business that issues the cash receipt. It must match the business linked to `Supplier-Key`.          | `Supplier-Key` header, `issuer` field in the request body |
| **Recipient**                                   | The person or business that receives the cash receipt.                                                   | `recipient` field in the request body                     |
| **Self-issuance (SELF)**                        | Issuance without recipient information.                                                                  | `recipient.type = SELF`                                   |
| **Recipient identifier (`recipient.value`)**    | A mobile phone number or business registration number that identifies the recipient. Omit it for `SELF`. | `recipient.value`                                         |
| **Issuance key (issuanceKey)**                  | The key that identifies an issuance request. Use it for cancellation requests.                           | `issuanceKey` in the issuance response                    |
| **Approval number (cashReceiptApprovalNumber)** | The cash receipt approval number assigned after successful issuance.                                     | Status and webhook responses                              |

<Info>
  For cash receipts, set **`Supplier-Key` to the issuer's key**. Enter the receiving party's information in `recipient`.
</Info>

## Related documents

* [Authentication guide](/en/api-introduction/authentication) - how to use `Supplier-Key`
* [Cash receipt guide](/en/api-introduction/cash-receipt-guide) - the cash receipt issuance and cancellation flow
* [Delegated issuance](/en/api-introduction/usecase-delegated) - how a platform issues on behalf of a supplier
* [Recipient identification number](/en/api-introduction/recipient-identification-number) - how to write the receiving side's identification number