SCHEMA_VALIDATION_FAILED: XML does not conform to FA(3) XSD schema

StandardKSeF FA(3), Polish national e-invoicing systemSeverityError: the invoice is rejectedSyntaxFA(3) XMLApplies toStructured invoices (FA(3) schema) submitted to the Polish KSeF. XSD codes come from the schema, semantic codes from the Ministry of Finance information sheet; KSeF rejects invoices that fail an error-level rule.

Official rule text

[SCHEMA_VALIDATION_FAILED] XML does not conform to FA(3) XSD schema

Why this error occurs

KSeF checks the FA(3) XML in two stages: XSD schema (structure, element order, data types, patterns such as NIP or dates) and semantic rules from the Ministry of Finance information sheet (consistency of amounts, annotations P_16 to P_23, roles of Podmiot2/Podmiot3, bank account formats, currency rates).

How to fix it

Fix the element named in the message. For XSD errors compare the element order and value pattern with the FA(3) schema; for semantic errors apply the cause and fix hints listed on this page. Re-validate before submitting to KSeF: a rejected invoice has no KSeF number and is not issued.

What the validator checks

Check levelxsd / schema

Typical causes

Invalid element order
Missing required elements
Invalid element values
Wrong namespace

Check your invoice

Drop your XML or PDF on the validator and every failed rule is linked to its page here. Free, no account, the file is not stored.

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Same check via API:

curl -F file=@invoice.xml https://einvoicechecker.com/v1/validate

Related rules

ELEMENT_NOT_ALLOWED Element not allowed at this location
INVALID_ELEMENT_VALUE Element value does not match schema constraints
REQUIRED_ELEMENT_MISSING Required element missing according to schema

Frequently asked questions

What does SCHEMA_VALIDATION_FAILED mean?

SCHEMA_VALIDATION_FAILED is a ksef fa(3) rule: XML does not conform to FA(3) XSD schema

Will my invoice be rejected because of SCHEMA_VALIDATION_FAILED?

Yes. SCHEMA_VALIDATION_FAILED is flagged "fatal"; validators (KoSIT, Peppol access points, the German ZRE/OZG-RE portals, KSeF) reject the invoice until it is fixed.

Which formats does SCHEMA_VALIDATION_FAILED apply to?

Structured invoices (FA(3) schema) submitted to the Polish KSeF. XSD codes come from the schema, semantic codes from the Ministry of Finance information sheet; KSeF rejects invoices that fail an error-level rule. Syntax: FA3.

Source: KSeF FA(3) schema 1-0E + semantic rules (@ksefuj/validator 0.4). Catalogue generated from the official rule sets on 2026-10-15.