
Electronic invoicing (e-invoicing) is significantly increasing and becoming more and more regulated by the introduction of business-to-government (B2G) and business-to-business (B2B) e-invoicing mandates in many countries around the globe. The introduction of electronic invoicing on a national level is a complex and challenging endeavour.
In this blog we would like to give a perspective and example of one country that has already implemented in practice a government e-invoicing and real time VAT reporting solution and therefore ensured mandatory e-invoicing on a national level.
Unifiedpost Group, a leading technology provider in the field of e-invoicing, e-payments and e-identity, has developed and implemented in practice a solution for the Serbian government that is currently in production and running live under the name “System eFaktura” (SEF).
Selected model and timeframe of implementation
The Serbian government opted for the fully Centralised model, based on which the SEF platform has been configured. The model has been introduced in phases and became fully live, and in production on a national level, from April 2022 for all B2G and B2B mandates.
Project dates:
- Platform licensing date - December 2019
- Setup, customisation and integration - 2020/2021
- E-invoicing law adopted - May 2021
- B2G mandate - May 2022
- B2B mandate - January 2023
In this model all companies, both government owned and private, are reachable in one system. There is only one e-invoice in the system between sender and receiver and therefore only one source of truth.
SEF provides the possibility to attach up to three PDF documents (for example purchase order, dispatch advice, contract) in a total size of 75 MB.
The law on e-invoicing allows companies to use the system directly (API/UI) or through certified invoice providers. Although the Serbian platform is a centralised government model that is free of charge, it has increased the emergence of commercial solutions, which have provided a lot of opportunities for e-invoicing providers and ERP integrators.
What is the main government objective?
The government’s main objective is to automate VAT reporting and improve the supervision of both the private and public sector, therefore significantly reducing the VAT tax gap as well as optimising state budget spendings.
Details on service
- Contracted by the Ministry of Finance.
- Hosted at the government ICT office and will be migrated to the Oracle cloud infrastructure (OCI) in 2024.
- Extended engagement: change requests, integrations, support and maintenance.
- SEF platform can be accessed via UI & API free of charge.
- All commercial e-invoicing platforms must integrate with SEF.
Interesting facts and figures
More than 220,000 companies have been onboarded onto the platform, including 10,000 government entities.
During 2023, 119 million electronic invoices were processed through the system. Around 300,000 electronic invoices were processed on a daily basis, while the peak of daily processing reached 700,000 electronic invoices. The majority of all electronic invoices are sent via API, 94%, while only 6% are using UI.

Next level and key integrations with System eFaktura
A major achievement is the upgrade of the System eFaktura with new integrations of industry, services and sectors that are of high importance for the government, such as: E-Customs, Retail eFiscalisation, E-Health system (procure to pay), as well as completely automatised VAT reporting.
Introducing the eFaktura World project
eFaktura World is Unifiedpost Group’s next generation e-invoicing solution for governments worldwide. The solution was designed and developed in 2023 based on EU standards and best practice from the Serbian project (SEF). With a new architecture design, the solution is fully modular, integrable, scalable and adaptable, with microservice architecture: based on EN-16931-1 invoicing semantic model and mapping to UBL structural model.
eFaktura World supports different government e-invoicing models including real-time reporting, clearance, centralised exchange and decentralised CTC and exchange (including the Peppol infrastructure).
What to find out more about eFaktura World?
Explore the full eFaktura World offering and see how we can help you to implement a national e-invoicing government solution.