About

Zugferdchen 🐴 is a free, anonymous debugging tool for electronic invoices, built around the Mustang (Mustangproject) ZUGFeRD / Factur-X / XRechnung validator.

No account, no login, no API key. Uploaded invoices live only for the duration of the request that carries them – invoice bytes, extracted XML and finding text are never written to disk and never logged. The only durable state is an anonymized usage counter.

Rate limits

Six actions per minute per IP. An action is a validation or an XML extraction; loading a page, reloading it, or reading the stats costs nothing.

API

Two stateless, unauthenticated endpoints:

curl -X POST -F "file=@invoice.pdf" https://www.zugferdchen.de/api/v1/validate
curl -X POST -F "file=@invoice.pdf" https://www.zugferdchen.de/api/v1/xml

validate returns the verdict, standard/profile/version and findings. xml returns the embedded CII as both a nested JSON tree and base64 XML.

Try it here

The same widget the home page uses, embedded in a plain Markdown page via a shortcode: