Missing required fields
Required UBL elements like ID, IssueDate or LegalMonetaryTotal are absent or empty.
Understand and fix UBL invoice errors
Validate UBL and Peppol invoices, explain XML errors in plain English, and check embedded PDF attachments directly in your browser.
Tools
Pick the tool you need. All checks run locally.
UBL Validator and Error Explainer
Find missing fields, structural problems and Peppol issues, and read plain-English explanations.
UBL Viewer
Render a UBL XML invoice as a readable invoice summary.
Embedded PDF checker
Check whether the invoice has a valid embedded PDF attachment.
UBL totals checker
Verify line, tax and payable totals against LegalMonetaryTotal.
UBL VAT checker
Compare declared and calculated VAT per category.
UBL field explainer
Search UBL fields and read what each XML path means.
Peppol BIS Billing checker
Check common Peppol BIS Billing 3.0 invoice issues.
Why UBL invoices fail
Totals don't match
Sum of line amounts, VAT and payable amount drift apart because of rounding or forgotten allowances.
Currency mismatches
Amounts use a different currencyID than DocumentCurrencyCode, which Peppol rejects.
Broken PDF attachments
EmbeddedDocumentBinaryObject contains invalid base64, missing mimeCode, or content that is not a PDF.
Wrong CustomizationID/ProfileID
The invoice is not labelled as Peppol BIS Billing 3.0, so access points won't accept it.
Schema-invalid XML
Tags are misspelled, namespaces are missing, or the file is not well-formed XML.
Files never uploaded
Every tool on UBLExplain is implemented as client-side JavaScript. Your UBL XML stays in the browser tab — there is no backend, no server upload, and no analytics on invoice contents.
Frequently asked questions
›What is a UBL invoice?
UBL (Universal Business Language) is a standard XML format for electronic invoices. UBL invoices include structured data such as supplier, customer, lines, VAT and totals, so receivers can process them automatically.
›Is my invoice uploaded anywhere?
No. Every tool on UBLExplain runs entirely in your browser. Your XML never leaves your device and is not stored.
›Does UBLExplain replace official Peppol validation?
No. UBLExplain performs helpful, browser-based checks and explanations, but it is not a substitute for official Peppol validation or access-point certification.
›Which UBL document types are supported?
The tools work with UBL 2.x Invoice and CreditNote documents, including Peppol BIS Billing 3.0 invoices.