# BR-63 Buyer electronic address must have a scheme identifier

The Buyer electronic address (BT-49) shall have a Scheme identifier that names the electronic address scheme.

## Problem Description

> **ERROR**: EN 16931 core business rule (CEN)

## Context and Significance

This is an EN 16931 core rule and the buyer-side counterpart of BR-62. The scheme of the buyer electronic address (BT-49-1) tells the sender how to interpret the receiving address, for example a Leitweg-ID (0204) for German public-sector buyers or a GLN (0088). The error usually appears when the buyer Leitweg-ID or e-mail address is copied without the schemeID attribute. The value must also belong to the EAS code list (BR-CL-25).

## Solution

Set the schemeID attribute on the buyer cbc:EndpointID to the EAS code that matches how the buyer receives invoices, for example 0204 for a German Leitweg-ID, 0088 for a GLN or EM for an e-mail address. In CII, set ram:BuyerTradeParty/ram:URIUniversalCommunication/ram:URIID/@schemeID.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-63)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-63)

## Valid Examples

- BT-49 = 04011000-12345-03 with schemeID="0204" (German Leitweg-ID)
- BT-49 = 4012345000016 with schemeID="0088" (GLN)

## Invalid Examples

- BT-49 EndpointID present but with no schemeID attribute

## Code Examples

### Valid XML
```
<cac:AccountingCustomerParty>
  <cac:Party>
    <cbc:EndpointID schemeID="0204">04011000-12345-03</cbc:EndpointID>
  </cac:Party>
</cac:AccountingCustomerParty>
```

### Invalid XML
```
<cac:AccountingCustomerParty>
  <cac:Party>
    <cbc:EndpointID>04011000-12345-03</cbc:EndpointID>
  </cac:Party>
</cac:AccountingCustomerParty>
```

## Affected Fields

- [BT-49 Buyer electronic address](/resources/xrechnung/bt-49-buyer-electronic-address)

## Related Rules

- [BR-62](/resources/kosit-validator-errors/br-62-seller-electronic-address-scheme-required)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.