Sovos.com
Contact SupportImplementation FAQ
Find answers to frequently-asked questions about working with Numer Identyfikacji Podatkowej (NIP) responses and understanding the integration workflow.
For information about how to respond to specific errors, see Error handling and retry logic.
- Where is the Krajowy System e-Faktur (KSeF) reference number?
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Look in the
<ad:Field name="ksefReferenceNumber">field in the<ext:UBLExtensions>object in the successful application response.CODE<ad:Field name="ksefReferenceNumber">9999999999-20251212-0100C0180F5F-05</ad:Field> - Where is the UPO (tax authority confirmation)?
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You can configure UPO to be received as an attachment that is returned as part of the notifications. The UPO attachment name field is
<cbc:URI schemeID="CanonicalInvoice">. - How do I trigger offline mode?
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Set
Transmission.OperationTypeto offline in your Standard Business Document (SBD) when submitting the invoice. Sovos generates both QR codes if both certificates are configured without attempting KSeF transmission. Your Type 2 certificate must be configured in your Sovos account to use offline mode. See Offline mode submission and Offline mode and retry behavior. - Can I use offline mode even when KSeF is available?
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Yes. Offline24 mode is designed for voluntary use as well as emergency situations. You can choose to issue invoices offline and submit them to KSeF the next business day as part of your normal workflow. This flexibility supports batch processing strategies and reduces real-time dependency on KSeF availability.
- What happens if my certificate expires?
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Expired certificates cause authentication failures. Monitor certificate expiration dates and renew at least 30 days before expiration. Request new certificates from the KSeF portal before expiration, according to the environment you need to work with.
- How long should I poll for a response?
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Most invoices clear within one to two minutes under normal conditions. If processing is delayed, contact Sovos support team.