In order to improve control over their VAT legislation, governments in various countries have been working for years to encourage the business community in their countries to conduct intercompany invoicing in a structured format (such as UBL) and to exchange these invoices with each other via special networks (such as Peppol), but despite many attempts to do so, there are still very few companies exchanging UBL invoices with each other, and therefore governments have now proceeded to make e-invoicing mandatory, as Belgium, for example, has done as of January 1, 2026, and many other countries will follow in the short term.

We are of the opinion that the business community has insufficient resources to bring this transition to a successful conclusion and therefore ask for your attention for our ProcurementDocumentManager WebApp, abbreviated PDM. We are of the opinion that with the PDM app, not only can the expected problems with e-invoicing be prevented, but that it adds so much quality to the e-invoicing process that companies will be eager to start using e-invoicing and mandatory requirements can be dispensed with.

In the following paragraphs, using 2 flowcharts, we indicate which problems we believe can be expected during the introduction of e-invoicing and how these problems can be prevented by using the PDM app. We do this not only using text and diagrams but also with LIVE exercises on the PDM app, which can be used live from this website and which you can also test; however, we will start with the diagrams first.

The quadrilateral Peppol e-invoicing model without the PDM App

The 1st diagram is a representation of the well-known quadrilateral Peppol model in which e-invoices are sent from supplier to customer via Peppol providers. In this diagram, the focus is strongly on the customer role so that it is clearly visible how the invoice flow proceeds at the customer when the PDM app is not used.

The crown jewel within the above e-invoicing model is that e-invoices are automatically posted to the customer's accounting system by their ERP app immediately upon receipt. This automatic posting is said to lead to significant work savings and result in faster payment of invoices. But what administrator wants to have unvalidated and even unseen invoices posted to their accounting system? And what entrepreneur would proceed to a quick payment of invoices that have not yet been seen by anyone? In short, in most cases, administrators will have no choice but to reverse the early invoice entry and, as before, create a new journal entry based on PDF invoices including underlying procurement documents, on the basis of which the invoice is posted again.

The quadrilateral Peppol e-invoicing model but now based on the PDM model

The 2nd diagram is also a representation of the well-known quadrilateral e-invoicing model, but now based on the PDM e-invoicing model. The characteristic and decisive difference that distinguishes the PDM app from the previous e-invoicing model is that procurement documents are not stored as a file or journal entry, but as Documents in the PDM database. The documents stored in the PDM app can be visualized as a document at any time within the PDM app. Furthermore, documents within the PDM app are “attached” to DocumentTrees of mutually related (FromQuoteToInvoice) documents, so that each document can be assessed at all times in conjunction with its related documents.

In the 2nd diagram, it is clearly visible that the various invoice flows within the PDM model proceed differently; simply compare the red and blue arrows from the 2 diagrams. In the PDM model, incoming invoices are not booked in the accounting system upon arrival, but are first uploaded to the customer's PDM App, where they are digitally linked in (FromQuoteToInvoice) DocumentTrees to related procurement documents such as waybills, delivery notes, photos, or even correspondence conducted between supplier and customer. This provides a solid basis upon which the invoices can be validated, approved, numbered, and coded. Only after this are they booked in the ERP application, after which they can be paid from the ERP app. Because invoices are digitally coded within the PDM app, these journal entries can optionally also be automatically imported/booked in the customer's ERP app, but this depends partly on the ERP app.

Within the PDM model, solutions are also offered for problems that have not even been addressed above; for example, outgoing invoices must also be traceable stored in a structured manner, and therefore they are stored in the PDM database just like incoming invoices, instead of being stored in printed form together with their underlying documents in folders in cabinets.

Another challenge companies face is that they must implement a two-track invoice archiving system, one for traditional PDF invoices and one for UBL invoices. Administrators will be forced to continue using traditional PDF invoices alongside UBL invoices, because although UBL invoices are human-readable, they are not, or hardly, human-interpretable. Administrators will therefore simply continue to manage their bookkeeping using PDF invoices, but in addition, they will also have to archive UBL invoices, whereby every UBL invoice must always be flawlessly traceable from the PDF invoice. We believe that most administrators will solve this by printing out both the PDF and the UBL sales and purchase invoices, stapling them together, storing them in binders, and archiving them. This is not only extremely labor-intensive but also highly inconsistent with sustainability and places a huge strain on archive space.

The PDM app offers an efficient digital and sustainable alternative to the 2-track paper invoicing archive, namely the side-by-side display of PDF and UBL invoices. You can see what is meant by this by logging into the PDM app, by first clicking on Login, after which you will arrive at a page in the PDM app displaying a number of documents that were previously uploaded to the PDM app via the menu option UploadUBL+PDF Docs. On each of the lines, you will see an UBL button and a PDF button, allowing the documents to be displayed side by side. In this way, UBL invoices are easily linked to each other and traceable. Please do not pay attention to the content of the various PDF and UBL invoices in these examples in the PDM app, however, as they do not match; this exercise is not about the content but about the SidebySide display technique. Incidentally, anyone is free to enter matching UBL and PDF invoices into the PDM app as a test; to do so, click on menu option Upload UBL+PDF Docs, select the relevant PDF and UBL invoice, and you can then upload them to the PDM app.

One of the many other PDM benefits that has not even been mentioned here yet is that accounting records are much more accessible remotely when using the PDM app. All documents that administrators, accountants, and perhaps even the tax authorities need for better control over VAT legislation are digitally accessible via the internet.

The age-old e-invoicing dream finally becoming a reality!

The technology of digitally linking related documents together via DocumentTrees in the PDM app is a digital alternative to the centuries-old, unsustainable, time-, space-, and paper-consuming method we have always used, namely: Stapling invoices to the underlying documents and storing them in binders/archives.

With the PDM app, it is possible to digitize the entire From Quote to Invoice process, which means that you can manage this entire process without having to print out a single document. The age-old dream of paperless invoicing from 15 to 20 years ago is becoming a reality and even being surpassed, because back then it was only about the digitization of invoices, but in the PDM app, not only are the invoices digitized, but the entire FromQuotetoInvoice process of procurement documents, which implies that many more trees can be saved than was already estimated at the time.