E-invoicing vs EDI: what UK businesses need to know

EDI (electronic data interchange) and e-invoicing both send invoices as structured data rather than PDFs. The difference is the plumbing: EDI is usually a private, point-to-point arrangement between trading partners, while Peppol e-invoicing is an open network where you connect once and can reach anyone else on it.

That matters because the UK's 2029 mandate will run on Peppol. If you invoice big customers by EDI today, you need to know whether that will still count.

What EDI is

EDI is the exchange of business documents between computer systems in an agreed structured format. It has been around since long before Peppol. The UN/EDIFACT standard, described in the government's consultation response as an international EDI standard published by the United Nations Economic Commission for Europe in 1987, is one of the best known. UK retail has its own long-standing EDI formats too.

A typical EDI set-up:

• The buyer (often a large retailer, manufacturer or distributor) specifies the message format and the rules.
• Each supplier is mapped and tested individually, often through an EDI provider or value-added network (VAN).
• Orders, despatch advice and invoices flow between the two systems automatically.

EDI works very well for high-volume relationships. Its weakness is that each connection is a separate project, and a supplier with ten EDI customers may face ten sets of requirements.

What Peppol e-invoicing is

Peppol is an international network and set of specifications, governed by OpenPeppol, a non-profit association under Belgian law. It began in 2008 as a European Commission-funded pilot.

Instead of building a link per customer, each business connects to one certified Access Point. Invoices travel in the four-corner model: supplier, supplier's Access Point, buyer's Access Point, buyer. The invoice format, Peppol BIS Billing 3.0, is a core invoice usage specification of the European standard EN 16931, and the network uses a directory and lookup service so the sender can find where to deliver.

On 23 June 2026 the government announced that "the electronic procurement system Peppol will be the core interoperability network for e-invoicing in the UK."

Side by side

	Traditional EDI	Peppol e-invoicing
Connection	Point-to-point or via a VAN, set up per trading partner	One Access Point reaches every Peppol participant
Who sets the format	Often the buyer, by agreement	Common specification (Peppol BIS Billing 3.0, based on EN 16931)
Typical syntax	EDIFACT, older UK retail formats, X12 and others	UBL (CII also supported by the specification)
Onboarding a new partner	Mapping and testing each time	Look up their Peppol ID and send
Documents	Orders, despatch advice, invoices, more	Invoices and credit notes; Peppol also has order and other messages
UK 2029 status	Not yet confirmed	Confirmed as the core network

Is an EDI invoice an e-invoice?

In a technical sense, yes: the government's own definition of e-invoicing is "the digital exchange of invoice data directly between buyers' and suppliers' financial systems". EDI invoices fit that description. They are a very different thing from a PDF.

Whether an EDI invoice will satisfy the legal mandate from April 2029 is a separate question, and the answer is not yet confirmed. Three things point to the issues the roadmap must settle:

• Peppol is the core network. The June 2026 announcement said the government "will continue to engage with stakeholders regarding the role of legacy systems which cannot interoperate in the future system."
• Standards are still being designed. The consultation response said the government would review whether to adopt an existing standard or design a UK-specific one.
• Flexibility was requested. One respondent recommended Peppol as the default channel "but allowing alternative channels by mutual agreement". The government has not said whether it will accept that.

Many respondents also flagged the difficulty of mixed formats. The consultation response listed "different standards across systems" such as UBL and EDIFACT as a barrier to seamless exchange.

What this could mean for EDI users

We do not know the final rules, so treat these as scenarios, not predictions:

1. EDI allowed by agreement, with Peppol as default. Existing EDI flows continue between partners who agree, but every business must be able to send and receive via Peppol.
2. Peppol required for VAT invoices, EDI kept for other documents. Orders and despatch advice stay on EDI; invoices move to Peppol.
3. Bridging. Many EDI providers already convert between formats. An EDI provider that is also a Peppol Access Point could convert your outbound EDI invoice into a Peppol invoice.

Whichever applies, the Peppol format may require data your EDI messages do not carry, or carry differently, such as VAT category codes or buyer references.

Questions to ask your EDI provider

• Are you a certified Peppol Access Point, or do you partner with one?
• Can you convert our existing EDI invoices to Peppol BIS Billing 3.0, and receive Peppol invoices into our system?
• How will you handle validation errors and invoice responses?
• What is your plan once the UK specification is published?

What to do now

• List which customers and suppliers you exchange EDI invoices with, and in which formats.
• Check which of your trading partners already have a Peppol ID. See Peppol directory lookup.
• Do not rip out working EDI yet. Wait for the roadmap at Budget 2026 on 28 October 2026 before making big changes.
• Read What is Peppol? and How to choose a Peppol Access Point.