# RechnungCheck (checkxrechnung.com)

> Free online validator for German e-invoices: XRechnung XML (UBL and CII) and ZUGFeRD PDF with embedded XML. Runs the official KoSIT validator with the official XRechnung configuration and returns rule codes (BR-...), locations and German fix hints. Files are processed in request memory only and not stored. Operated by Bobook Limited (Dublin, Ireland).
> Kostenloser Online-Validator für E-Rechnungen (XRechnung UBL/CII, ZUGFeRD PDF+XML) mit offiziellen KoSIT-Regeln. Dateien werden nicht gespeichert.

## What it checks
- Formats: XRechnung XML (UBL and CII); ZUGFeRD PDF when an XML is embedded
- Engine: KoSIT validator + official XRechnung configuration
- Rule versions: KoSIT 1.6.3 · XRechnung 3.0.2 · EN 16931 1.3.16 (configuration release 2026-08-31, scenarios.xml dated 2026-09-02)
- Result: rule code (BR-...), location, German fix hint, and rule_url when that code has a public page; pass / valid with warnings / reject / not an e-invoice / unclear
- Max file size: 5 MB for POST /v1/validate and the website. 10 MB for POST /v1/zugferd/validate and POST /v1/zugferd/extract.

## Not included
- No Peppol access point, no invoice editor, no portal submission, no legal or tax advice
- A file that passes here can still be rejected by ZRE/OZG-RE or other portals (portal/bank overlays)
- Validity is decided by official rules, never by an AI model

## Privacy
- Invoice files are processed in request memory, not written to disk, not logged as XML and not sent to a language model (persisted: false)
- Technical events contain metadata only (byte size, type, error count)

## API / Batch
- POST /v1/validate is live. No API key. Multipart field "file". Same check as the website.
- POST /v1/zugferd/validate checks a ZUGFeRD / Factur-X PDF: PDF/A-3 structure (veraPDF when that program is installed, otherwise a labelled structure check), extracts factur-x.xml / zugferd-invoice.xml / xrechnung.xml, detects profile MINIMUM, BASIC WL, BASIC, EN16931, EXTENDED or XRECHNUNG, and validates the XML with the EN 16931 CII Schematron. Profile XRECHNUNG also runs the XRechnung CII Schematron. Issues include rule_url when a page exists under /fehler/.
- POST /v1/zugferd/extract returns the embedded XML and a JSON summary (invoice number, date, seller, buyer, totals, profile).
- Free: 50 validations per IP per UTC day, and 10 per minute, shared by /v1/validate, /v1/zugferd/validate and /v1/zugferd/extract. Above that: HTTP 429, Retry-After, link to the waitlist.
- Max file size: 5 MB on POST /v1/validate, 10 MB on the ZUGFeRD routes. Larger files: HTTP 413.
- Pages: https://checkxrechnung.com/zugferd and https://checkxrechnung.com/en/zugferd
- Batch and higher volume: waitlist, from EUR 79/month; joining is free, charged only after confirmation
- Join: https://checkxrechnung.com/api-waitlist (or email info@bobook.club, subject "checkxrechnung API waitlist")
- Docs: https://checkxrechnung.com/en/docs (Deutsch: https://checkxrechnung.com/docs)
- OpenAPI: https://checkxrechnung.com/openapi.json

## Key pages
- [Validate an e-invoice](https://checkxrechnung.com/) (English: https://checkxrechnung.com/en/)
- [XRechnung validator](https://checkxrechnung.com/xrechnung-validator)
- [ZUGFeRD validator](https://checkxrechnung.com/zugferd-validator)
- [ZUGFeRD / Factur-X API](https://checkxrechnung.com/zugferd) (English: https://checkxrechnung.com/en/zugferd)
- [KoSIT validator online](https://checkxrechnung.com/kosit-validator-online)
- [Error codes, one page per rule](https://checkxrechnung.com/fehler/) (e.g. https://checkxrechnung.com/fehler/br-de-15). English: https://checkxrechnung.com/en/errors/ and https://checkxrechnung.com/en/errors/br-de-15. POST /v1/validate adds rule_url on issues that match one of these pages.
- [Leitweg-ID format and checker](https://checkxrechnung.com/leitweg-id)
- [XRechnung or ZUGFeRD?](https://checkxrechnung.com/xrechnung-oder-zugferd)
- [Sample files](https://checkxrechnung.com/samples)
- [Changelog](https://checkxrechnung.com/changelog)
- [Datenschutz](https://checkxrechnung.com/datenschutz) · [Impressum](https://checkxrechnung.com/impressum)

## Contact
Bobook Limited, Venture Hub, 136 Capel Street, Dublin 1, D01 T2C9, Ireland · info@bobook.club