type: [string, "null"]
enum:
  - WISE
  - KLARNA_OB_SEPA
  - KLARNA_OB_SEPA_INSTANT
  - WALLET
  - SEPA_FILE
  - MANUAL
  - PAYMENT_SKIPPED
  - EXTERNAL_DIRECT_DEBIT
  - PAY_BY_BANK
  - N_A
  - APPLE_PAY
  - ANDROID_PAY
  - M4M
  - CARD
  - UNKNOWN_DEFAULT_OPEN_API
default: UNKNOWN_DEFAULT_OPEN_API
description: |
  Payment channel/method indicating how payment was processed.
  
  Common channels across invoice and reimbursement:
  - **N_A**: Not applicable or not specified
  - **MANUAL**: Manual payment processing
  - **WALLET**: Payment via digital wallet
  - **SEPA_FILE**: SEPA file transfer (previously SEPA in invoice data)
  - **EXTERNAL_DIRECT_DEBIT**: External direct debit (previously DIRECT_DEBIT in invoice data)
  - **PAY_BY_BANK**: Pay by bank transfer
  
  Reimbursement-specific channels:
  - **WISE**: Payment via Wise
  - **KLARNA_OB_SEPA**: Klarna Open Banking SEPA transfer
  - **KLARNA_OB_SEPA_INSTANT**: Klarna Open Banking SEPA instant transfer
  - **PAYMENT_SKIPPED**: Payment was intentionally skipped
  
  Card transaction specific channels:
  - **APPLE_PAY**
  - **ANDROID_PAY**
  - **M4M**
  - **CARD**
example: "N_A"

