Why five corners and not one gateway
Many countries built a central portal to which every invoice is uploaded before reaching the customer (the "clearance" model). The UAE chose Peppol's decentralised model, called Decentralised CTC: exchange happens between accredited providers over an open network, and tax reporting runs in parallel. In practice: there is no government website where you register invoices by hand, and no invoice "approval number" to wait for from the FTA before delivery. The invoice is valid once your customer receives it through the system.
The eleven steps, per chapter 5.1 of the guidelines
- The supplier (corner 1) hands the invoice data to its provider in whatever format the two agreed — from the accounting system, a file, or manual entry in the provider's interface.
- Corner 2 validates the data and converts it into an electronic invoice in the PINT AE format (XML).
- Corner 2 transmits the invoice over the Peppol network to the customer's provider (corner 3).
- In parallel, corner 2 reports the tax data to the FTA (corner 5).
- Corner 3 validates the invoice and sends an electronic confirmation to corner 2.
- Corner 3 delivers the invoice to the customer (corner 4) in the format the two agreed.
- After validation, corner 3 also reports the tax data to the FTA — the authority hears the story from both sides.
- Corner 5 sends an electronic confirmation to corner 2 once the data is received.
- Corner 5 confirms to corner 3 as well.
- Corner 2 forwards the confirmations to the supplier (corner 1).
- Corner 3 forwards the confirmations to the customer (corner 4).
Three terms you will meet in the contract
- Peppol participant identifier. Your business's address on the network, issued through your provider. In the official sample it looks like 0235:1234567890. The supplier is responsible for obtaining its customer's identifier (item 5 in the responsibilities table); its provider is responsible for looking it up on the network.
- UUID. A globally unique identifier your provider generates for every electronic invoice to prevent duplicates. It does not replace your sequential invoice number; it is added to it.
- Electronic confirmation. Not an FTA "approval" of the invoice, but an acknowledgement that the data was received. The invoice's tax validity remains your responsibility.
Who does what: the responsibility stays with you
The responsibilities table in chapter 5.2 splits seven tasks between supplier, buyer and provider. The line that matters is a footnote: "Practically, ASPs are engaged by suppliers to carry out these activities although the compliance obligation remains with the supplier (or buyer in the case of self-billed invoices)." Translation: if your provider errs, the penalty carries your name. So you ask before signing: what happens when an invoice is rejected? Who tells me? Within how long? And what is the contractual remedy if the fault was theirs?
What this means for choosing a provider
- Corner 2 and corner 3 are the same product from two angles: if your provider is excellent at sending (corner 2) and weak at receiving (corner 3), you pay for its weak half every time a supplier sends you an invoice. Ask to see the receiving screen before you sign.
- Exchange over an open network means a customer on a different provider receives your invoice with no special arrangement. Do not accept a "discount" for having your customers on the same provider.
- The electronic invoice is XML with no QR code (chapter 5.3). The human-readable PDF is an extra the provider offers for customers not yet onboarded — it is not the legal invoice.