# BT-17 Tender or lot reference

Reference to the tender, lot, or procurement package connected to the invoice.

## Quick answer

> **Invoice basics**: Core document identifiers, dates, process identifiers, and high-level invoice context.

- [Validate XML](/en/xrechnung-validator?source=resource&bt=BT-17)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&bt=BT-17)

## In plain language

Reference to the tender, lot, or procurement package connected to the invoice.

Reference to the tender, lot, or procurement package connected to the invoice.

This is especially relevant in public procurement, framework agreements, and project contracts with lot structures.

## What you usually enter here

Tender or lot identifier

Typical valid values include: LOT-04, TENDER-2026-17

Optional according to EN 16931-1.

## What goes wrong often

Avoid values like: , AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

## Examples in context

This is especially relevant in public procurement, framework agreements, and project contracts with lot structures.

Optional according to EN 16931-1.

## Valid Examples

- LOT-04
- TENDER-2026-17

## Invalid Examples

- AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

## Related Fields

This is especially relevant in public procurement, framework agreements, and project contracts with lot structures.

- [BT-12 Contract reference](/resources/xrechnung/bt-12-contract-reference)

## XML mapping and field facts

Open the technical reference if you need XML paths, validator rule codes, legal wording, or schema-specific mapping details.

### Field ID:
BT-17

### Data Type:
text

### Cardinality:
0..1

### Requirement:
Optional

### Max Length:
50 characters

### Since Version:
Optional

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cac:OriginatorDocumentReference/cbc:ID
```

### CII (UN/CEFACT) Syntax
```
/CrossIndustryInvoice/SupplyChainTradeTransaction/ApplicableHeaderTradeAgreement/ram:AdditionalReferencedDocument/ram:IssuerAssignedID
```

## Create an XRechnung from your PDF

The converter reads the invoice and shows the fields it found before download, so you can check and correct the values. No PDF? Fill in the XRechnung directly in the form.

- [Convert invoice](/en/pdf-to-xrechnung)
- [Fill in XRechnung in the form](/en/create-xrechnung)

Download requires an account. Subscriptions from €10/month with annual billing (excl. taxes), or €5 per conversion (excl. taxes) without a subscription.

## Why the standard cares about this field

### Business Context
This is especially relevant in public procurement, framework agreements, and project contracts with lot structures.

### Legal Requirement
Optional according to EN 16931-1.

## Official sources and tools

- [KoSIT Validator](https://erechnungsvalidator.service-bw.de/)
- [XRechnung Standard](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)