The Merchant Accounting System does not need to follow a strict predefined sequence when generating the Invoice Number for inclusion in the Invoice Reference Number (IRN). However, there are specific guidelines to ensure compatibility with the FIRS e-lnvoice System:
Guidelines for Invoice Number Generation:
- Uniqueness: Each invoice number must be unique within the Merchant Accounting System to prevent duplication and ensure traceability.
- Alphanumeric Format: The invoice number can contain letters and numbers but must not include special characters (e.g., #, @, $, etc.).
- No Character Limit: There is no specific character limit for the invoice number. Merchants can generate numbers of any length, provided they meet the above criteria.
- Integration Readiness: The generated invoice number should seamlessly integrate with the other components of the IRN, including the Service ID and Timestamp, to create the final IRN in the required format (e.g., INV00XX-94ND90NR-20240611).
Important Notes:
- The sequence or format of the invoice number is entirely at the discretion of the merchant, provided it adheres to the above rules.
- Merchants are encouraged to use a logical numbering system to enhance internal recordkeeping and reconciliation.
