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

# Core concepts

> Understand the core concepts in the Creditor API

## Concepts

### Creditors

A creditor is the company or private individual to whom money is owed — that is you. All data you create and read through this API belongs to your creditor. Your `creditorId` is shown on the API page in the creditor portal.

### Customers

Represents your end-customer relationship. A customer has a reference id, which can be the customer number, client id, membership number, patient id, or another identifier from your own system. Each customer can have one or more users attached — typically the debtor, and optionally alternative contacts.

### Cases

A case represents a specific debt or matter associated with a customer. Each customer can have multiple cases. A case is always linked to a customer and includes a list of case vouchers, which represent the amount owed. A case moves through the statuses `PENDING`, `VERIFIED` and `ENDED`. When a case is ended, an end reason describes why — for example `PAID`.

<Tip>
  You do not create cases directly. You only create the customer and add case
  vouchers to the customer. The platform automatically determines when to
  create a new case or update an existing one.
</Tip>

### Case vouchers

A case voucher is a financial entry linked to a specific case, representing an amount that is either owed or credited. Case vouchers are used to define the financial components of a case and can include various types of entries such as invoices, credit notes, reminder fees and deposits.

Each case voucher includes key information such as the amount, currency, source, date, and a reference id (e.g. an invoice number). Amounts are in the base currency unit: 1.00 should be sent as 100. A negative amount (e.g. -100) represents a debt, while a positive amount (e.g. +100) represents a credit note or deposit.

The type of a voucher is defined by its voucher type. See the [Voucher types](/api-reference/voucher-types) page for the list of ids.