Published: August 22, 2026
Free toolInternal act generatorThe internal act is step two on this list. Fill in your data and the document assembles itself.Open →The order matters
The most common mistake is buying the certificate first, then discovering the premises were never registered or the internal act does not exist. The certificate is close to last.
The whole process takes a few working days if nothing is unusual. The waiting is on the certificate and on tax portal access if you do not have it yet.
Step 1: access to the tax portal
Everything is filed electronically through the ePorezna system. Access requires an NIAS-accepted credential: an eID card with a reader, your bank's mToken, or a business certificate.
- For a sole trader or single-member company, a bank mToken or eID card is fastest.
- If your accountant files for you, they need a power of attorney in the system.
- Make sure the person who will actually file has access, not only the owner.
- ePorezna, sign in the official Tax Administration portal
- Croatian Tax Administration, fiscalization guidance and forms at the source
Step 2: the internal act
Before filing anything you must define your premises, their codes, the payment devices and the invoice numbering rule. That goes into an internal act, which is not filed but shown on inspection.
The usual mistake is a mismatch between the codes in the act and the codes in the filing. They must be identical.
Step 3: register your premises
Premises are registered electronically through ePorezna, before the first receipt is issued from them.
- The premise code, identical to the internal act.
- The address. For an online store you give the webshop address, because a webshop counts as a premise.
- The activity carried out there and the opening hours.
- The start date from which you issue receipts there.
Every later change is filed the same way, before it takes effect.
Step 4: the fiscalization certificate
Signing messages to the Tax Administration requires an application certificate for fiscalization. It is not the same as the certificate you use to sign in to the tax portal.
- In Croatia it is issued by FINA and by Certilia. Both are accepted; they differ in price and in how you collect it.
- It is issued to the company and its OIB, not to a person.
- It expires and must be renewed. Note the expiry date, because fiscalization stops when it lapses.
- A free demo certificate exists for testing against the tax authority test environment only.
Prices and lead times change, so check them with the issuer directly rather than relying on figures quoted in articles.
- FINA, fiscalization certificates issuer; terms and pricing on their site
- Certilia the other issuer, by AKD
Step 5: load the certificate into your software
The certificate is loaded into the system that issues invoices. It then signs each receipt and sends it to the Tax Administration, which returns the JIR.
- Guard the file and its password like a bank password. Whoever holds it can issue receipts in your name.
- A serious system stores it encrypted and never shows it back.
- Do not e-mail it or keep it in a shared folder.
Step 6: test, then go live
Before the first real receipt, run the process against the test environment with the demo certificate, then switch to production.
- Issue a test receipt and confirm the JIR comes back and prints on the document.
- Confirm numbering runs sequentially in the number-premise-device format.
- Try a storno, because refunds and cancellations will come.
- Check what happens when the tax service does not respond: the receipt is still issued and delivered later.
Commonly missed
Cash-handling rules apply regardless of software. From 2026 bank-transfer orders are fiscalized too, not only card and cash, so a webshop previously outside the obligation now falls inside it.
If you are VAT-registered, from 2026 you also face the B2B e-invoice obligation, which requires a contract with an information intermediary. That is a separate step.
Frequently asked questions
- Do I need a certificate if I only sell online?
- Yes. A webshop is a business premise and its receipts are fiscalized. From 2026 this includes bank-transfer orders.
- FINA or Certilia, what is the difference?
- Functionally there is no difference for fiscalization; both are accepted. They differ in price, lead time and collection process.
- Can I fiscalize without an internal act?
- Technically the software will work, but in an inspection the act is the document that ties your invoice numbers to your premises.
- What if the certificate expires?
- Fiscalization stops and receipts cannot be signed. Start the renewal before expiry, because issuance takes time.
- Does this apply to a flat-rate sole trader?
- Yes; the fiscalization obligation does not depend on the taxation method.
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