Fiskalizacija HR for OpenCart — fiscal receipts to the Croatian Tax Administration CIS (ZKI, JIR, QR)

Fiskalizacija HR for OpenCart is a module for web shops in Croatia running OpenCart 4, 3 or 2.3. In Croatia every receipt to an end customer must be fiscalised, whatever the payment method. The shop computes the ZKI protection code, sends the signed receipt to the CIS fiscalisation service of the Tax Administration (Porezna uprava) and prints the JIR identifier and a QR code on the receipt. The module does this for OpenCart orders straight to CIS with your own certificate, with no third-party service in between and no monthly subscription.

Running WooCommerce? There is a separate version for it — Fiskalizacija HR for WooCommerce, with the same signature, ZKI and request format.

What you need. The OIB of your company or obrt; the web shop registered as business premises in ePorezna (the module does not do this — it only needs the premises code, e.g. WEB1); a fiscalisation certificate issued for your OIB, e.g. FINA “Fiskal”. The CIS test environment accepts only DEMO certificates, production only production ones.

Honestly about testing. The module was built and checked against the official CIS technical specification “Tehnička specifikacija za korisnike” v2.7 and the FiskalizacijaSchema / WSDL 1.10: every generated request — regular receipts, late delivery, storno with negative amounts, receipts with a buyer OIB — passed the official XSD and an independent signature check, and every ZKI was recomputed separately. The full run was done on local shops with OpenCart 4.1.0.3, 4.0.2.3 (pdo driver), 3.0.5.0 and 2.3.0.2 on PHP 7.0 against a model of the CIS answers: success, refusals, outages. The real CIS test server answered us only without a DEMO certificate, which requires a Croatian OIB that CatCode does not have. So you get the live JIR in your own 7-day Pro trial with a FINA DEMO certificate. If CIS answers differently from the specification, we will fix it promptly.

Responsibility for the receipt data stays with the shop. The module takes amounts and taxes from the OpenCart order, and the VAT system, premises and device codes, operator, payment methods and the category of lines without VAT from your settings. Review these settings with your accountant before switching to production.

What the customer sees

The customer gets a receipt: shop details and OIB, the number in the broj/prostor/uređaj format, date and time in Croatian time, operator, payment method, items with VAT rates, the VAT breakdown, ZKI, JIR and a QR code linking to the receipt check on porezna.gov.hr. The receipt page opens only through a keyed link and prints with the “Print” button.

In the customer account, in the order history, a “Fiscal receipt” block appears with the QR code, number, total, ZKI, JIR and a link to the receipt. Customers never see other people’s receipts; on a phone the block has no horizontal scroll.

Pro. A company paying by card or in cash can enter its OIB in the “Company OIB” field at checkout — the default one and CatCode One Page Checkout. The module checks the check digit: a wrong OIB stops the checkout next to the field. After the JIR the customer gets the receipt by e-mail.

What the admin gets

• Extensions → Modules → CatCode Fiskalizacija HR with the “Receipts”, “Settings”, “Tools” and “Licence” tabs (in Croatian when the admin is in Croatian).
• Receipt register: number and time, order, buyer and buyer OIB, total, payment method, status (Fiscalised, waiting for JIR, refused, late delivery), JIR and ZKI; a status filter and search by number, JIR, ZKI, OIB or order.
• “Send receipts without a JIR now” sends the queue at once, “Send again” re-sends a refused receipt after the settings are fixed.
• The top of the page shows the environment (TEST or PRODUCTION) and warnings: the certificate has expired or is about to, the OIB in the certificate differs from the settings, a DEMO certificate in production, receipts without a JIR for more than 30 minutes.

The receipt page shows everything that went to CIS and came back: number, status, ZKI, JIR, whether the answer signature was verified, the number of attempts, the receipt lines and VAT breakdown, all receipts of the order, and below them the signed request and the answer XML. In the test environment there is the provjera check — CIS compares the receipt without fiscalising it.

The order page gets a “Fiscal receipt” panel with the receipts and storno receipts of the order, the “Issue and fiscalise the receipt” button and the buyer OIB field for the next receipt (Pro). Each step is written to the order history.

How it works — step by step

1. Certificate. Upload a .p12 with its password or a .pem. The module shows the subject, issuer, OIB and validity, stores the private key encrypted (the encryption key lives in system/storage, not in the database) and takes the OIB from the certificate into the settings. “Check the connection” tests the link to CIS with an echo message.
2. Issuer and numbering. OIB, whether you are in the VAT system, name and address for the receipt, premises code, device number, sequence (per premises P or per device N), the first number of the year if you continue a series from another program, operator OIB and label (empty means the issuer OIB and “WEB”).
3. Payments and taxes. A G, K, T or O code for each payment module; the category of lines without VAT; codes of order totals that are payments rather than sales (voucher and credit by default).
4. Order. When an order gets the chosen status, the module checks totals and rates locally, only then takes the next number, computes the ZKI, builds and signs the RacunZahtjev and sends it to CIS. Setting the status again does not create a second receipt.
5. Answer. CIS returns the JIR — the module verifies the answer signature and stores the JIR. An s001–s005 or s013 error marks the receipt “Refused”, the reason is shown in the register, “Send again” after the fix.
6. Outage. CIS did not answer — the receipt is already valid with its ZKI, and the module delivers it later with the NakDost flag and a new message ID, with a growing pause from 1 to 360 minutes.

VAT is taken from the order’s tax rows and grouped by rate — 25 %, 13 %, 5 % or 0 %. A rate CIS does not accept is stopped before sending with an explanation, and no number is used. Coupons are spread over the rates, shipping goes by its own tax, and rounding cents are reconciled so the receipt total matches the order total. Lines without tax go as VAT-exempt by default, a product with a real 0 % rate as VAT at 0 %; other categories can be forced.

Pro. A refund produces a storno receipt with negative amounts at the same rates — automatically on the “Refunded” and “Reversed” statuses (configurable) or with a button. The buyer OIB goes to CIS only with payment G or K, as the specification requires. An order in another currency gets a receipt in euro at the shop’s rate, past orders can be fiscalised in bulk by ID, the register exports to CSV, and the owner gets an e-mail when a receipt is refused or still has no JIR after 5 attempts.

Under the hood

• CIS: RacunZahtjev (fiscalisation), ProvjeraZahtjev (check, test only), echo (connection); cistest.apis-it.hr:8449 and cis.porezna-uprava.hr:8449, SOAP 1.1.
• ZKI — MD5 of the RSA-SHA256 signature of OIB + date and time + number + premises + device + total, as in section 12 of specification v2.7.
• Request signature — enveloped XMLDSig: Exclusive C14N, RSA-SHA256. RSA-SHA1 is not used: test CIS refuses it since 1 July 2026, production from 1 January 2027.
• TLS and the answer: the connection is verified with the bundled FINA certificates (Fina RDC 2020, Fina Demo CA 2020), the answer signature with the service certificate.
• Locked numbering: concurrent orders never get the same number and leave no gaps; separate counters for test and production. Tested with 40 concurrent orders and a register of 3,000 receipts.
• OpenCart events: the module does not modify core files — it works through events, so it works with CatCode One Page Checkout (tested on 4.1 and 3.0).
• Uninstalling: OpenCart removes the settings and the certificate, while the register and counters stay as tax records; the “Delete data on uninstall” option removes them too.

How to install

1. OpenCart 4: Extensions → Installer → upload cc_fiskalhr.ocmod.zip (do not rename the archive) and press Install. OpenCart 3: Extensions → Installer → cc_fiskalhr-oc3.ocmod.zip. OpenCart 2.3: upload the contents of the upload/ folder from cc_fiskalhr-oc2.ocmod.zip to the shop root (FTP or the hosting file manager).
2. Extensions → Modules → CatCode Fiskalizacija HR → Install → Edit.
3. Settings: upload the DEMO certificate, press “Check the connection”, fill in the OIB, premises code, device, operator and payment methods, switch fiscalisation on in the TEST environment.
4. Place test orders, check the receipts in the register and with the provjera check.
5. Show the settings to your accountant, switch the environment to PRODUCTION and upload the production certificate.
6. For Pro: paste the licence key from the e-mail after payment or start the 7-day trial on the “Licence” tab.