# Peppol ID Northern Ireland: GB or XI VAT number?

> There is no XI scheme in Peppol. Northern Ireland businesses normally register a 9932 ID using their GB VAT number; XI is for EU goods trade documentation.

- Canonical URL: https://einvoices.uk/news/peppol-id-northern-ireland-xi
- Published: 20 October 2026 (2026-10-20)
- Last updated: 20 October 2026 (2026-10-20) (not updated since publication)
- Author: Floris Lindenaar, Editor, e-invoicing expert (https://einvoices.uk/authors/floris-lindenaar)
- Publisher: einvoices.uk (https://einvoices.uk)
- Type: Guide
- Topics: Northern Ireland, Peppol, VAT, Technical
- Language: en-GB (UK English); covers the United Kingdom

## Sources

- [OpenPeppol eDEC Code Lists](https://docs.peppol.eu/edelivery/codelists/)
- [VATNIEU2100 - The Single Market concept: background - HMRC internal manual - GOV.UK](https://www.gov.uk/hmrc-internal-manuals/vat-northern-ireland-and-the-eu/vatnieu2100)
- [Register for VAT: Selling or moving goods between Northern Ireland and the EU - GOV.UK](https://www.gov.uk/register-for-vat/selling-or-moving-goods-between-northern-ireland-and-the-eu)
- [Peppol Policy for use of Identifiers v4.4.0](https://docs.peppol.eu/edelivery/policies/Peppol-EDN-Policy-for-use-of-identifiers-4.4.0-2025-02-06.pdf)
- [Peppol BIS Billing](https://docs.peppol.eu/poacc/billing/3.0/bis/)
- [Peppol BIS Billing 3.0 - ISO 3166-1 Alpha2 country codes](https://docs.peppol.eu/poacc/billing/3.0/codelist/ISO3166/)
- [Tax update 2026: simplification, modernisation and fairness summary](https://www.gov.uk/government/publications/summary-of-tax-update-2026-simplification-modernisation-and-fairness/tax-update-2026-simplification-modernisation-and-fairness-summary)

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There is **no XI scheme** in Peppol. A VAT-registered Northern Ireland business would normally register a Peppol ID under scheme **9932 (United Kingdom VAT number)**, the same as a business in Great Britain, for example `9932:gb123456789` (a made-up number). The XI prefix is a separate VAT matter. It affects what you print as your VAT number on certain invoices, not your Peppol address.

## Two different things: your address and your VAT number

On a Peppol invoice, your identity appears in two separate places:

| Element | Business term | Purpose | NI example |
|---|---|---|---|
| `cbc:EndpointID` | BT-34 Seller electronic address | Routing: where the invoice is delivered over Peppol | `schemeID="9932"` `GB123456789` |
| `cac:PartyTaxScheme/cbc:CompanyID` | BT-31 Seller VAT identifier | Tax data shown on the invoice | `GB123456789` or `XI123456789` |

The **electronic address** must match a Peppol ID registered in an SMP. Otherwise nobody can deliver to it. The **VAT identifier** is invoice content, and it follows VAT rules.

So an NI business can keep a single Peppol ID and still show an XI VAT number on the invoices that need one.

## When the XI prefix applies

HMRC's manual on Northern Ireland and the EU says businesses trading goods between Northern Ireland and the EU need, "where appropriate", to add "the 'XI' prefix before their normal 9-digit UK VAT number" when communicating with EU suppliers or customers.

The same page says the XI prefix is **not** required:

- for services between Northern Ireland and the EU
- within the internal UK market
- for goods or services between the UK and the rest of the world

GOV.UK's registration guidance adds: "You must use your XI VAT registration number on all documentation when communicating with EU customers or suppliers", including invoices. You start using it once HMRC confirms you are eligible.

In practice, then:

| Invoice | VAT identifier (BT-31) | Peppol ID (EndpointID) |
|---|---|---|
| NI supplier to GB customer (goods or services) | GB123456789 | 9932:gb123456789 |
| NI supplier to NI customer | GB123456789 | 9932:gb123456789 |
| NI supplier of goods to an EU customer | XI123456789 | 9932:gb123456789 |
| NI supplier of services to an EU customer | GB123456789 | 9932:gb123456789 |

This table reflects HMRC's general XI guidance. It is not tax advice, so check HMRC's guidance for your own transactions.

## Can you register `9932:xi123456789`?

Technically, the Peppol identifier policy allows any value made of letters, digits and a few symbols, and the 9932 entry has no validation rule. So nothing in the Peppol rules stops a provider registering `9932:xi123456789`. But:

- 9932 is defined as "United Kingdom VAT number", and its listed country is GB.
- Your customers' systems will most likely look you up under the GB form.
- When we searched the Peppol Directory on 20 October 2026, Northern Ireland registrations we found used the `9932:gb...` form.

Registering an XI-based Peppol ID as well as, or instead of, the GB one is likely to cause missed lookups. Unless a buyer specifically asks for it, the GB form is the safer choice.

## Does the validation accept XI?

Yes. EN 16931 rule **BR-CO-09** requires the seller and buyer VAT identifiers to start with an ISO 3166-1 alpha-2 country prefix ("Nevertheless, Greece may use the prefix 'EL'"). The EN 16931 UBL validation artefacts used by Peppol BIS Billing 3.0 include `XI` in their list of accepted prefixes. So `XI123456789` in BT-31 will pass that rule.

The postal address country is a separate question. `GB` is the official ISO 3166-1 code for the whole United Kingdom, including Northern Ireland. But the country code list published with Peppol BIS Billing 3.0 also contains `XI`, "United Kingdom (Northern Ireland)", so an address with country `XI` will also validate. No UK rule yet says which one NI businesses should use, so ask your provider what it does.

## Worked example

Lough Components Ltd (fictional) in Belfast has UK VAT number 123 4567 89 and has been confirmed to use XI for EU goods trade.

- **Peppol ID:** `9932:gb123456789`, registered once by its provider.
- **Invoice to a customer in Manchester:** BT-31 `GB123456789`. Buyer's EndpointID is the customer's Peppol ID.
- **Invoice for goods to a customer in Dublin:** BT-31 `XI123456789`. Same seller EndpointID. Buyer's EndpointID is the Irish customer's Peppol ID, which may use an Irish scheme.

## What is not settled for the UK mandate

**Confirmed:** Peppol will be the core interoperability network for UK e-invoicing, with mandatory e-invoicing for B2B and B2G VAT invoices from April 2029.

**Not yet confirmed (as of 20 October 2026):**

- whether UK rules will say which scheme and value format NI businesses must register under
- whether any UK-specific validation will check that BT-31 uses GB or XI correctly for the type of supply
- whether NI postal addresses should use country code GB or XI
- how the mandate will interact with EU e-invoicing rules for NI goods trade with EU member states

See [E-invoicing in Northern Ireland and XI VAT numbers](https://einvoices.uk/news/e-invoicing-northern-ireland-xi-vat) for the wider picture.

## What to do now

1. Keep one Peppol ID based on your GB VAT number unless a customer asks otherwise.
2. Make sure your invoicing software can switch BT-31 between GB and XI by type of supply, not by customer alone.
3. Ask your provider how it validates VAT prefixes.
4. Related reading: [Peppol participant IDs in the UK](https://einvoices.uk/news/peppol-participant-id-uk) and [EAS codes 9932 and 0088](https://einvoices.uk/news/peppol-eas-codes-uk-9932-0088).

## Frequently asked questions

### Is there an XI Peppol scheme for Northern Ireland?

No. The Peppol participant identifier code list (v9.7) has no XI or Northern Ireland entry. The UK VAT scheme is 9932 (GB:VAT).

### What Peppol ID should a Northern Ireland business use?

Usually the same as any UK VAT-registered business: scheme 9932 with your VAT number, for example 9932:gb123456789. The XI number has the same nine digits, but it is a VAT prefix for EU goods trade, not a Peppol scheme.

### Should I put my XI number on a Peppol invoice?

Only where HMRC says the XI prefix applies, mainly invoices for goods traded between Northern Ireland and the EU. Then the seller VAT identifier (BT-31) would be XI123456789. For UK internal trade and services, use your GB number.

### Does Peppol accept XI as a VAT prefix?

EN 16931 rule BR-CO-09 requires a country prefix on VAT identifiers, and the EN 16931 validation artefacts include XI among the accepted prefixes, so an XI VAT identifier passes that check.

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How to cite: "Peppol ID Northern Ireland: GB or XI VAT number?", einvoices.uk, 20 October 2026, https://einvoices.uk/news/peppol-id-northern-ireland-xi

einvoices.uk is an independent publication and is not affiliated with HMRC or the UK Government. Nothing here is tax advice; check the sources and official GOV.UK guidance before acting.