Leitweg-ID

Short definition

The Leitweg-ID is a unique routing identifier used to address invoices to German public authorities. It is the mandatory field BT-10 (Buyer reference) of every B2G XRechnung. Without a valid Leitweg-ID, the invoice is rejected by the central intake portal ZRE (federal) or OZG-RE (state) — no matter how correct the rest of the invoice is.

It is published by KoSIT (Coordination Office for IT Standards). Every federal, state or public-law entity receives at least one Leitweg-ID.

Structure

A Leitweg-ID always consists of three parts, separated by hyphens:

[coarse address] - [fine address] - [checksum]

Example: 991-33333TEST-33

Part	Length	Meaning
Coarse address	2–12 chars	identifies federal, state or public-law entity
Fine address	0–30 chars	identifies the specific office/department (optional)
Checksum	2 digits	Modulo-97 checksum over the first two parts

The coarse address follows fixed prefixes: 991 marks test Leitweg-IDs, 992…997 denote different federal tiers, 99001… numbers the German federal states in order.

Where the Leitweg-ID appears

Regardless of XML syntax, the Leitweg-ID always sits in the same BT field:

UBL:

<cbc:BuyerReference>991-33333TEST-33</cbc:BuyerReference>

CII:

<ram:BuyerReference>991-33333TEST-33</ram:BuyerReference>

It is not the recipient’s tax ID, not the VAT ID, not a customer number — it is a standalone routing key the authority provides.

Calculating the checksum

The checksum uses Modulo 97 (similar to IBAN):

1. Concatenate coarse and fine address (no hyphens)
2. Convert every letter into a number (A=10, B=11, …, Z=35)
3. Append the digits 00 to the result
4. Divide by 97, take the remainder
5. Checksum = 98 − remainder, two digits with leading zero

The Dokmatiq API computes the checksum automatically when only coarse and fine parts are supplied — or validates a complete Leitweg-ID coming from an ERP system.

Validation via API

curl -X POST https://api.dokmatiq.com/v1/einvoice/leitweg/validate \
  -H "Authorization: Bearer $DOKMATIQ_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "leitwegId": "991-33333TEST-33" }'

Response: { "valid": true, "parsed": { "coarse": "991", "fine": "33333TEST", "checksum": "33" }, "type": "test" }

Test IDs (991-…) are flagged explicitly — preventing a test invoice from accidentally landing in a production intake.

How do you find the right Leitweg-ID?

• Federal authorities: published via the Federal Office of Justice / KoSIT portal; most agencies state it actively on invoices or in tender documents
• States and municipalities: handled individually, often via state portals or requested directly from the issuing office
• Private sector: has no Leitweg-ID — field BT-10 stays empty or carries other references

Common pitfalls

1. Wrong checksum — the most frequent rejection; compute it automatically rather than retyping it from a Word document
2. Leitweg-ID in the wrong BT field — it belongs in BuyerReference (BT-10), not EndpointID (BT-49)
3. Production ID in test environment (or vice versa) — test IDs begin with 991
4. Outdated Leitweg-IDs — some authorities have migrated their IDs; legacy values are no longer accepted