Validate, explain, generate & convert e-invoices
With the official KoSIT validator result.
E-Rechnungen prüfen, erklären, erzeugen und konvertieren — mit amtlichem KoSIT-Prüfergebnis.
XRechnung (UBL & CII), ZUGFeRD/Factur-X and EN 16931 — as an API, an MCP server, and a free web tool.
Check an e-invoice for freeTry it now — no signup, no key:
curl --data-binary @invoice.xml \ "https://api.invowerk.dev/v1/validate?explain=true&lang=en"What is checked? The three check classes (BMF classification)
Formal check
Well-formedness, the EN 16931 XSD and syntax: is the file a structurally valid e-invoice at all?
Business rules
The CEN and XRechnung Schematron rules (EN 16931): required fields, totals logic, code lists — with plain-language explanations for every rule that fires.
Not machine-checkable content
Whether the figures reflect the real transaction is something no format validator can judge — substantive correctness stays a human review.
Keine steuerliche Beratung (no tax advice). Invowerk checks and generates the technical format only — field and rule guidance, never a tax or legal assessment.
Plans
Free
€0/mo
500 credits / month
Essential
€9/mo
2000 credits / month
Scale
€29/mo
8000 credits / month