REQUIRED_ELEMENT_MISSING: Required element missing according to 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

[REQUIRED_ELEMENT_MISSING] Required element missing according to 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

Mandatory element not provided
Incomplete structure

Check your invoice

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

Frequently asked questions

What does REQUIRED_ELEMENT_MISSING mean?

REQUIRED_ELEMENT_MISSING is a ksef fa(3) rule: Required element missing according to schema

Will my invoice be rejected because of REQUIRED_ELEMENT_MISSING?

Yes. REQUIRED_ELEMENT_MISSING 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 REQUIRED_ELEMENT_MISSING 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.