Guide
SEF and e-invoicing: obligations, deadlines and common errors
SEF is the free state platform for e-invoices: the response deadlines, user authorizations, electronic VAT recording and the errors that come up in practice, and we can run all of it for you.
You must use SEF if you are a VAT payer or you invoice the public sector, while flat-rate traders usually do not have to. The platform itself is free, and the only unavoidable cost is a qualified electronic certificate for logging in. In practice the money is lost on deadlines rather than on the certificate: a received invoice you never responded to goes to automatic rejection, and a rejected invoice gives no right to deduct input VAT. Below are the deadlines for responding and for electronic VAT recording, a checklist for setting the account up, and the errors that come up most often in SEF, with what each one means. If you need bookkeeping support for SEF, we run all of it for you.
What you should know
- An e-invoice is mandatory if you are a VAT payer or you deal with the public sector; between private companies (B2B) it has been mandatory since 1 January 2023. Flat-rate traders are not obligatory users, but register when they invoice the public sector. If you are only now entering the VAT system, the duty to use SEF arrives together with the VAT payer status.
- The SEF platform is free. The only unavoidable cost is a qualified electronic certificate to log in (about 3,000 to 5,000 dinars a year). Access needs an eID.gov.rs account and that certificate; a simple password is not enough.
- Access is granted through authorizations: the legal representative or administrator adds users and assigns each a role (issuing invoices, accepting or rejecting, recording VAT). An account with no role assigned can do nothing, so set the roles up before the first invoice, not on the day you need to send one.
- Deadlines matter. In the private sector you accept or reject a received invoice within 15 days; if you do not respond, after a reminder and 5 more days it is automatically rejected on day 20. For the public sector, silence means acceptance. So review statuses weekly and keep the rest of your dates in the tax calendar.
- An invoice's status affects VAT. Only an accepted invoice can be used to deduct input VAT, so a rejected or auto-rejected invoice means a lost deduction, which can cost you.
- VAT recording (e-PDV) is also done electronically through SEF, within 10 days of the end of the tax period. That data ties into what goes on the VAT return, so we treat recording and filing as one job rather than two separate ones.
- Penalties for lapses are real: for a company 200,000 to 2,000,000 dinars, for an entrepreneur 50,000 to 500,000, and for the responsible person 50,000 to 150,000 dinars. The key detail is that no penalty applies if you spot and correct the error yourself before a tax audit begins.
- The amendments from Official Gazette 109/2025 apply to tax periods starting after 31 March 2026: an e-invoice is required for retail sales to corporate-card holders, internal invoices are formalized, and the pre-filled VAT return is postponed to periods after 31 December 2026.
- The mistakes repeat month after month and they are always the same four: the login fails because there is no valid certificate, a user cannot issue an invoice because no role was assigned, an invoice is rejected over a wrong PIB, amount or tax rate, and a received invoice is lost because nobody responded in time. All four are solved with setup and routine, not with extra software.
- Electronic operations do not stop at SEF. The movement of goods is tracked by the electronic delivery note system. The rules for retail turnover are explained in our guide to fiscalization.
| Type of entity | SEF usage status | What it means in practice |
|---|---|---|
| VAT payers | Must use SEF | They issue and receive e-invoices through SEF and record the VAT calculation electronically within 10 days of the end of the tax period. |
| Public-sector entities | Must use SEF | For them silence on a received invoice counts as acceptance, so there is no automatic rejection as in the private sector. |
| Flat-rate traders | Voluntary users | They are not obligatory users, but must register when they invoice a public-sector client. |
| Agricultural holdings | Voluntary users | There is no duty until they register themselves, and entering the VAT system turns SEF into an obligation. |
| Other individuals | Voluntary users | They register only if they choose to; nothing is imposed on them automatically. |
How we handle it
- 01 Registration and authorizations We register you on SEF and set up user authorizations, so everyone in the company has exactly the role they need, from issuing invoices to recording VAT.
- 02 Issuing e-invoices We prepare and issue e-invoices with correct buyer data, tax ID (PIB), amounts, and tax rates, and send them through SEF within the legal deadlines.
- 03 Tracking statuses We monitor the statuses of issued and received invoices (sent, accepted, rejected) and respond in time, keeping the prescribed response deadlines in mind.
- 04 Reviewing received invoices We check incoming e-invoices and compare them against the documentation, then accept the correct ones and reject those with errors, with a clear explanation.
- 05 Electronic VAT recording We carry out electronic recording of VAT in SEF, generally within deadlines tied to the end of the tax period and in line with the regulations in force.
- 06 Reconciliation and filing We connect the SEF data with your bookkeeping and VAT return and inform you in good time about changes to the e-invoicing regulations.
Frequently asked questions
Do I have to use e-invoices and SEF at all?
If you are a VAT payer or you invoice the public sector, yes: e-invoices via SEF are mandatory, and B2B (between private companies) has been mandatory since 1 January 2023. Flat-rate traders are not obligatory users, but must register when they invoice a public-sector client.
How much does SEF cost?
The SEF platform itself is free. The only unavoidable cost is a qualified electronic certificate needed to log in, roughly 3,000 to 5,000 RSD per year. Invoicing software that connects to SEF is optional and separate.
Why can I not log in to SEF?
Logging in needs two things: an eID.gov.rs account and a qualified electronic certificate. A plain password is not enough, so if the certificate is not on the computer or is no longer valid, the login will fail. The certificate is an annual cost of about 3,000 to 5,000 dinars, and it is worth renewing it ahead of time rather than on the day you must send an invoice.
An employee has an account but cannot issue an invoice. What does that mean?
It means the right role has not been assigned. Access in SEF runs through authorizations granted by the legal representative or the administrator, and the roles are separate: issuing invoices, accepting or rejecting received invoices, and recording VAT. Someone allowed to accept invoices is not automatically allowed to issue them, so check the roles before the work stalls.
What happens if I ignore a received e-invoice?
In the private sector you have 15 days to accept or reject it; after a reminder and 5 more days, an unanswered invoice is automatically rejected on day 20. A rejected invoice cannot be used to deduct input VAT, so staying silent can cost you money.
An invoice was rejected although I did nothing. How?
That is automatic rejection caused by silence. In the private sector you have 15 days to respond, then a reminder arrives and 5 more days pass, and on day 20 an invoice you never answered is rejected on its own. The consequence is not only administrative, because a rejected invoice does not go into the input VAT deduction. So received invoices should be reviewed during the month, not just before the VAT return.
The buyer rejected my e-invoice. What now?
A rejection means the buyer found an error, most often in the buyer data, the PIB, the amount or the tax rate. Correct the data and send the invoice again, because a rejected invoice gives no right to deduct input VAT. The same applies when you are the one receiving: compare invoices against the documentation, accept the correct ones, and reject only with a clear explanation so the other side knows what to fix.
How do I know an issued invoice reached the buyer?
By its status. Every invoice in SEF carries a status, from sent to accepted or rejected, and that is the only reliable indicator of what happened to it. If the status does not move, the buyer has not responded, so count on the 15 day deadline and automatic rejection on day 20. With the public sector it is the other way round, because there silence means acceptance.
What changed for e-invoices on 1 April 2026?
Amendments published in Official Gazette 109/2025 apply to tax periods starting after 31 March 2026: e-invoices are now required for retail sales to corporate-card holders, internal invoices are formalized, and the pre-filled (preliminary) VAT return is postponed to periods after 31 December 2026.
What are the fines for e-invoicing mistakes?
For a company the fine is 200,000 to 2,000,000 RSD, for an entrepreneur 50,000 to 500,000 RSD, and for the responsible person 50,000 to 150,000 RSD. If you find and correct the error yourself before a tax audit starts, the penalty is not applied.
How to start a company
A guide to starting a company in Serbia: choosing a legal form, APR registration and first obligations.
Read moreSole trader, flat-rate or LLC: which to choose
An overview of the three Serbian legal forms (flat-rate sole trader, sole trader on business books, and an LLC) compared by liability, taxation, bookkeeping and capital, so you can pick the form that pays off best for you.
Read moreOpening a company in Serbia for foreigners
A separate process for foreign founders: documents, APR, physical KES/QES, banking and the required visit to Serbia.
Read moreReady to hand your books to the experts?
Book a free 30-minute consultation. No obligations, just a clear plan for your finances.