Invoice UUID (Unique Universal Identifier)

A UUID (Universally Unique Identifier) in the MyInvois context is a globally unique alphanumeric string assigned by LHDN's platform to every e-invoice that passes validation. The UUID is the primary proof that an invoice has been officially processed and recognised by LHDN. It appears on the validated invoice, in MyInvois dashboards for both supplier and buyer, and is embedded in the QR code that accompanies every validated e-invoice.

The UUID is generated by MyInvois at the moment of successful validation — not before submission, and not by the submitting business. This means that a supplier cannot pre-assign or predict their invoice's UUID; it is generated server-side by LHDN's systems. The UUID follows the standard UUID format (a 32-character hexadecimal string in the form 8-4-4-4-12, e.g., "550e8400-e29b-41d4-a716-446655440000") and is guaranteed to be unique across all invoices in the MyInvois system.

How businesses should use the UUID: once a UUID is received for a submitted invoice, it should be stored in the business's accounting or ERP system against the corresponding invoice record. The UUID serves as the primary reference for any subsequent actions related to that invoice — including issuing a credit note (which must reference the original invoice UUID), responding to LHDN audit queries, and verifying the invoice's status in the MyInvois portal. Buyers should also record the UUIDs of invoices they receive for their records.

Why the UUID matters for records and compliance: Malaysia's Income Tax Act requires businesses to maintain tax records for a minimum of seven years. A UUID-stamped invoice is the definitive version of that tax record — it proves the document's authenticity and that it was registered with LHDN. In a tax audit, LHDN can instantly look up any UUID to verify whether the invoice in a business's records matches what was submitted. Discrepancies between a business's invoices and the UUID-linked records in MyInvois are a significant audit red flag.

Businesses building API-based integrations with MyInvois should implement robust UUID storage and retrieval. The MyInvois API returns the UUID in the response payload after successful validation. This UUID must be captured and persisted — it cannot be retrieved again from LHDN in bulk (though it can be looked up individually). Systems should log the UUID alongside the submission timestamp, invoice number, and validation status for each submitted invoice.