# XRechnung required fields: a practical checklist

- Date: 2026-04-28
- Modified: 2026-08-29
- Reviewed: August 29, 2026
- Reading time: 2 min read

Check the XRechnung fields that most often block validation, with exact BT numbers and the related BR-DE rules.

> Reviewed against KoSIT validator configuration, BMI e-invoice introduction.

XRechnung combines the European EN 16931 invoice model with German rules. A field can be optional in the European model and still be required by XRechnung. The active validator report is the final check.

## Document and party basics

- **Invoice:** invoice number (BT-1), issue date (BT-2), type code (BT-3), currency (BT-5), and specification identifier (BT-24).
- **Seller and buyer:** legal names, postal addresses, country codes, and the identifiers required for the transaction.
- **Lines and totals:** item names, quantities, units, prices, VAT categories, VAT rates, line totals, tax totals, and payable amount.
## Address fields: do not make BT-35 mandatory

**BT-35 is optional:** it is the first seller address line. Do not reject an otherwise complete address only because BT-35 is empty. For XRechnung, BR-DE-3 requires seller city (BT-37), and BR-DE-4 requires seller post code (BT-38). The seller country code is BT-40.

## Seller contact is required

**BR-DE-2** requires SELLER CONTACT (BG-6). **BR-DE-5** requires seller contact point (BT-41). **BR-DE-6** requires seller contact telephone number (BT-42). **BR-DE-7** requires seller contact email address (BT-43). Use a monitored business contact.

## Buyer reference and tax identifiers

**BR-DE-15** requires Buyer reference (BT-10). For a domestic B2B tax invoice without an agreed buyer reference, the BMF permits `-`. For a public recipient, enter the routing reference supplied by that recipient, often a Leitweg-ID; a placeholder can fail recipient routing.

**BR-DE-16** requires at least one of Seller VAT identifier (BT-31), Seller tax registration identifier (BT-32), or Seller tax representative VAT identifier (BT-63) when the listed VAT categories are used.

## Electronic addresses need a scheme

Despite its Peppol name and origin, XRechnung 3.0 KoSIT validation enforces PEPPOL-EN16931-R020 as a fatal rule for every XRechnung channel: the seller electronic address (BT-34) needs a schemeID. `9930:DE123456789` is one endpoint example, not a fixed XRechnung value. Use the seller identifier and scheme that apply to the invoice.

## Final check before sending

- Confirm the recipient, channel, and required profile.
- Check source values against the invoice, especially tax IDs and totals.
- Generate the UBL or CII XML and run the matching KoSIT configuration.
- Correct the source data and generate again. Keep manual review for uncertain source fields.

## Official references

- [KoSIT validator configuration](https://github.com/itplr-kosit/validator-configuration-xrechnung)
- [BMI e-invoice introduction](https://www.bmi.bund.de/DE/themen/moderne-verwaltung/verwaltungsmodernisierung/einfuehrung-e-rechnung/einfuehrung-e-rechnung-node.html)