Idempotency Key

If a network failure occurs during invoice submission, the invoice may be accepted by Vertex e-Invoicing without being confirmed by the calling system. As a result, the invoice status may display an error. Retrying the request without safeguards can result in duplicate submissions.

To prevent duplicates, include an Idempotency-Key HTTP header with each request. The server enforces uniqueness based on this value.

Resubmission rules
• Correct the document (content must differ from the prior submission).
• Do not reuse the same idempotency key unless the content is identical.
• The receiving tax authority may require a new identifier in a corrected submission (for example a new value in the /ubl:Invoice/cbc:UUID)

This approach ensures proper handling of corrections while preventing unintended duplicate processing.

To generate an idempotency key, do one of the following:
• Generate a new unique idempotency key (for example, a GUID) for each submission attempt.
• Use a hash of the document content (such as SHA 256) as the idempotency key, ensuring it changes automatically when the content changes.