Regular readers of this blog will already be aware that electronic invoicing has become mandatory for all B2B transactions in Belgium and Poland as of January 1st and February 1st respectively. Not a problem for our Retarus Global E-Invoicing customers.
Belgium: Delays due to unregistered taxpayers
Belgium already rolled out its mandatory B2B e-invoicing regime at the start of 2026. Dozens of Retarus’ customers who booked the service by November and undertook the necessary preparations in their ERP systems (particularly regarding EN compliance and the Peppol ID), were all integrated successfully into the Peppol network on schedule. This means that these customers have already been sending and receiving e-invoices for more than a month now.
However, many of the businesses subject to the regulations have apparently not managed to meet the deadline. The cause of failure we have most often encountered is participants who were not registered on time, leading to unnecessary delays in implementation and significantly increasing communication efforts with business partners and their providers.
This once again highlights just how critical it is to opt for the right tech provider. Retarus, for instance, has gained many years of practical know-how as a holder of the necessary Peppol certifications for inbound and outbound data traffic and has extensive experience setting up a large number of Peppol connections across Europe.
Poland: Touch and go
Where Poland is concerned, it would be fair to characterize January as still somewhat turbulent. The government was still fine-tuning the technical specifications for KSeF 2.0 until the very last minute, meaning that the productive system only actually went live for users on February 1st. This placed considerable strain on the development and integration team at Retarus, not to mention the nerves of our customers. Nevertheless, we were able to successfully connect all customers to KSeF before the stipulated deadline in Poland.
Compared to Belgium, Poland has introduced a significantly more complex e-invoicing system. The interchange of digital invoices is required to take place by way of a central platform (KSeF), which can only be addressed via API. What’s more, Poland is using a proprietary XML format in the Polish language, which consequently deviates from international norms and complicates integration.
Retarus was early to start integration into the first version of KSeF, allowing us the opportunity to transfer the experience we gathered there into v2. There were new challenges, however, including changes in the management of certificates, for which the Polish authorities had introduced its own portal. In addition, many of our customers found the portal complex to use and error-prone.
Leveraging competent local tax consultants is advisable
Users supported by knowledgeable tax law experts were able to complete these administrative tasks more reliably and considerably faster. Accordingly, we have advised our customers to opt for a combination of a reliable service provider and a competent local tax consultant, to ensure that even the most challenging e-invoicing requirements can be met within the stipulated timeframes.
When it comes to e-invoicing, there is barely a moment to catch one’s breath. The UAE and France, not to mention Germany and a large number of other countries, are poised to introduce e-invoicing. To ensure reliable and timely compliance with digital invoicing requirements, simply get in touch with us!
