E-invoicing in Bulgaria from 2028: how NISSEF, electronic invoices and the link with the NRA will work

• creation of structured electronic invoices and notes to them;
• receipt of data on invoices created through external ERP, accounting or other software systems;
• automatic semantic checking of the information;
• generation of a unique compliance code;
• notification of the supplier and the recipient;
• access to data on structured electronic invoices issued and received;
• storage of the data on these documents. Strategy

This means that the NRA will not receive invoice information later through traditional monthly reporting. For invoices within the scope of the new regime, the data will be passed to the NRA immediately and in real time. Strategy

What is a structured electronic invoice?

A PDF invoice is not the same as a structured electronic invoice

Under the proposed Article 120a, a structured electronic invoice will be an invoice that at the same time:

1. meets the requirements of the VAT Act;
2. is issued, transmitted and received in a structured electronic format that allows automatic processing;
3. meets the applicable European e-invoicing standard;
4. has a unique compliance code generated by the national system. Strategy

Additional structured data is also planned, including codes for goods and services and information on the supplier’s accounts. The exact technical requirements are to be set by an ordinance of the Minister of Finance. Strategy

What will the NRA’s role be?

This is one of the most significant changes.

In the current model, a company issues an invoice in its ERP system or accounting software, sends the document to the customer, and the data later goes into tax reporting.

The proposed model puts the NRA inside the e-invoicing process itself.

When an invoice is created through an external system, for example BORA Business Suite, the specified data will be sent in real time to the NRA’s information system.

The system will run an automatic check and, if the invoice passes, will generate a unique compliance code (UKS). Strategy

What is the unique compliance code (UKS)?

The UKS is one of the key elements of the proposed model.

Under the draft, a structured electronic invoice will be considered issued at the moment the national information system generates the unique compliance code. Strategy

In other words, the process will roughly look like this:

BORA Business Suite → NRA/NISSEF → check → UKS → invoice
This is a significant difference from the current process, where generating the invoice in the ERP system practically completes its issue.

What will issuing an invoice through BORA Business Suite look like?

If the proposed model is implemented, the process in BORA Business Suite (BORA BS) could look like this:

1. Creating the invoice

The user creates the invoice in the usual way in BORA Business Suite, for example in the “Customers” or “Shop” module.

2. Automatic submission to the NRA

BORA BS converts the necessary data into the required structured electronic format and sends it to NISSEF.

3. Automatic check

The national information system runs a semantic check of the document against the regulatory requirements.

4. Generating the UKS

If the check passes, the system generates a unique compliance code.

5. Returning the UKS to BORA BS

BORA Business Suite receives the code automatically and links it to the invoice.

6. Issuing and delivering the document

According to the published draft, the invoice is considered issued when a UKS has been generated for it. The draft provides that it is considered received by the customer at the same moment, while the supplier still has to send it to the recipient electronically. Strategy

What happens if the invoice contains an error?

This is another important practical effect.

The data sent from an ERP or other external system will go through an automatic compliance check.

If a mismatch is found, NISSEF will return an error message. The published draft provides that the mismatch must be fixed within 48 hours, under a procedure to be set out in the ordinance of the Minister of Finance. Strategy

This means that the quality of the data in the ERP system will matter even more.
A wrong UIC, an incorrect goods or service code, a missing mandatory detail or another structural error can lead to a mismatch being found at once.

What will change for businesses?

The change will not be just technical.
It will affect the whole process, from creating the sale to accounting and VAT reporting.

The current model

The typical process today is:

ERP → invoice → PDF/print → customer → monthly ledgers and VAT return

The proposed new model

With structured e-invoicing the process changes roughly to:

ERP → structured data → NISSEF/NRA → automatic check → UKS → issued invoice → customer

The ERP system will no longer just create an invoice. It will have to communicate automatically with the NRA’s information infrastructure and handle the responses, errors and status of every document.

Will the VAT ledgers be dropped?

The draft also provides for a major change in this area.
It proposes that the NRA provide every registered person with a pre-generated draft VAT return, compiled automatically from the data the revenue administration already has, including structured electronic invoices and customs declarations. Strategy

Companies will be able to correct, add to or delete certain data before the return is submitted.
This is an important part of the move from periodic tax reporting to a model where much of the information reaches the tax administration at the level of the individual transaction and practically in real time.

And what does ViDA have to do with it?

The Bulgarian changes should also be seen in the context of the European initiative VAT in the Digital Age, ViDA.
In March 2025 the EU adopted Directive (EU) 2025/516, which amends the European VAT rules. Among its main areas are e-invoicing and digital reporting of transaction data. The European rules make structured e-invoicing a key part of the future VAT system. Eur-Lex
For businesses this means that e-invoicing is not an isolated Bulgarian project but part of a much larger European transformation.

What does this mean for ERP systems?

For ERP systems the change is significant.

Software will need to handle not only the accounting information in the invoice, but also:

• the structured electronic format;
• the new mandatory data and code lists;
• communication with NISSEF;
• sending data in real time;
• receiving and storing the UKS;
• processing mismatch messages;
• resubmission after correction;
• the status of the invoice;
• electronic sending and receiving of documents;
• traceability between the ERP document and the data registered with the NRA.

For companies that issue a large number of invoices every day, this integration will be critical.

BORA ViDA: preparing BORA Business Suite for the new model

BORA Solutions is developing BORA ViDA, a feature for BORA Business Suite designed to prepare the system for the requirements of structured e-invoicing and digital VAT reporting.

The aim is for the process to stay as automated as possible for the user:

creating an invoice in BORA BS → automatic communication with NISSEF → check → receiving the UKS → recording the result in BORA Business Suite.

The technical implementation will follow the finally adopted regulatory requirements, the NRA’s specifications and the upcoming ordinance of the Minister of Finance.

Why should companies start preparing early?

Introducing structured e-invoicing means changes not only to the software but also to:

• product and goods master data;
• goods and service codes;
• customer and supplier data;
• internal procedures for issuing and correcting invoices;
• integrations between ERP, online shops, POS systems and other applications;
• the organisation of accounting and sales processes.

That is why 2027 is likely to be a key year for preparing, analysing and testing companies’ systems, if the proposed schedule for introduction from 1 January 2028 is kept.

Important
At the date of publication, the regulatory texts on NISSEF and structured e-invoicing are part of a published draft amendment to the VAT Act. Some of the technical rules are still to be set by an ordinance of the Minister of Finance. BORA Solutions will update this information if the regulatory framework changes.