Accounts payable e-invoicing in the UK: a guide for AP teams

For accounts payable, e-invoicing means supplier invoices arrive as data in your system, not as PDFs in an inbox. From April 2029, VAT invoices between UK businesses must be e-invoices, exchanged over Peppol, so AP teams need a way to receive them, check them and route them to approval.

This guide covers what changes in the purchase-to-pay process and what to do about it.

What is confirmed

• E-invoicing becomes mandatory for VAT invoices from April 2029 (government consultation response).
• The model is decentralised: no government portal sits between you and your suppliers.
• Peppol is the network. The GOV.UK Tax update 2026 summary says: "The government has announced that the electronic procurement system Peppol will be the core interoperability network for e-invoicing in the UK."
• No real-time reporting to HMRC alongside the mandate.

Still open: the exact data standard, exemptions, phasing and the timetable for guidance. Expect detail in the roadmap at Budget 2026 on 28 October 2026.

How a supplier invoice will reach you

1. The supplier raises the invoice in its software.
2. Its Access Point looks up your Peppol ID and finds where to deliver it.
3. Your Access Point receives it.
4. Your AP or ERP software imports it.

Two consequences for AP. First, you must be registered on Peppol with an ID your suppliers can find. Second, Peppol invoices must conform to the Peppol BIS Billing 3.0 rules, and service providers typically validate documents against them, so much basic format checking happens before the invoice reaches you. That catches malformed invoices; it does not tell you whether you owe the money.

AP process, before and after

Step	Typical today	With e-invoicing
Receipt	Email inbox, post, supplier portals	One Peppol channel into your system
Capture	Manual keying or OCR scanning	Structured data, no keying
Format checks	Done by a person, if at all	Automated Peppol validation
Matching	Manual against PO and goods receipt	Automated two- or three-way matching on PO and line data
Query or rejection	Email or phone	Optional Peppol invoice response
Archive	PDF folders	Store the e-invoice data and any attachment

The invoice response: tell suppliers where they stand

Peppol has a standard message, the Invoice Response, that buyers can send back to suppliers. According to the Peppol specification (BIS Invoice Response 3.2), statuses include:

Code	Meaning
AB	Acknowledged: received and readable
IP	In process
UQ	Under query: waiting for the supplier
CA	Conditionally accepted
RE	Rejected (final)
AP	Accepted: approved, payment next
PD	Paid (final)

It is optional in general. But a buyer that supports it must be able to report at least AB, RE and AP, and if you send responses, the first should be provided within three working days. The specification describes its purpose as giving suppliers structured feedback so they can act early and so fewer status queries need to be handled manually.

Questions to ask your AP or ERP provider

1. Can we receive Peppol invoices and credit notes directly into the AP module?
2. Which Access Point do you use, and is it a Peppol certified service provider?
3. How are invoices that fail our own business rules (for example, missing PO) handled?
4. Can we send Invoice Responses, and which status codes are supported?
5. How are attachments (timesheets, delivery notes) stored and displayed? See invoice attachments.
6. Can we run Peppol alongside OCR and email intake during the transition?
7. How is the original e-invoice archived, and can we export it?

For ERP users, see our ERP e-invoicing guide.

Data you need to get right

E-invoicing makes your own data matter more, because suppliers' systems use it.

• Your legal entity details. Each company in a group needs correct name, address and VAT number, and its own Peppol registration. Check VAT group treatment.
• Buyer reference and PO numbers. Decide what suppliers must quote. Peppol carries a buyer reference (BT-10) and order reference; see buyer reference in Peppol.
• Supplier master data. VAT numbers, bank details and Peppol IDs, de-duplicated. See master data clean-up.
• Tolerance rules. Price and quantity tolerances for automatic matching.

Controls and fraud

Structured invoices reduce some fraud risks, such as doctored PDFs, but not all. Keep:

• independent verification of bank detail changes, even if the request arrives as structured data;
• checks that the sending Peppol ID belongs to the supplier on your master file;
• segregation between people who maintain suppliers and people who approve payments.

Records

HMRC says VAT records should generally be kept for at least six years (VAT Notice 700/21). Make sure the received e-invoice is stored, not only the posted journal, and that you can retrieve it for a VAT enquiry. See e-invoice archiving and retention.

Supplier communication

You cannot switch on receiving and expect every supplier to be ready the same day. Segment suppliers by volume, tell the largest first, and publish your Peppol ID on purchase orders and onboarding forms. Our supplier onboarding guide has a step-by-step plan.

What to do now

• Count invoices received per month and by channel.
• Ask your AP software provider the seven questions above.
• Decide your PO and buyer reference rules.
• Start a supplier data clean-up.
• Add AP to your wider e-invoicing project plan and readiness checklist.