Terms of use

In force from 1 September 2026 · Amended 14 September 2026 (section 7a) · Changed 4 October 2026 · Otkucaj (otkucaj.com)

Where these terms describe what the regulations require, that is our understanding of them, not legal advice. The regulations themselves prevail.

This English version is provided for convenience. If the two differ in meaning, the Serbian version prevails, because these terms are governed by the law of the Republic of Serbia.

1. The service and the provider

Otkucaj is an ESIR, an electronic invoice issuing system (a web application and an API) for taxpayers subject to fiscalization in the Republic of Serbia. The software is made and the service provided by Saša Mihajlović pr Računovodstveni poslovi TEFIS Vlasotince (below: "Tefis" or "the provider").

2. Definitions

• The service: the Otkucaj application, its API, the documentation, the supporting tools, and every change and new version of those components.
• The user: a business (an entrepreneur or a legal entity) that uses the service, in its own name or on behalf of the taxpayer it represents.
• An account: a sign-in account, a point of sale, an API key, or any other form of access to the service the provider grants to the user.
• PFR: the processor of fiscal invoices, local (L-PFR) or virtual (V-PFR), within the meaning of the electronic fiscalization regulations.
• SUF: the Fiscalization Management System of the Tax Administration of the Republic of Serbia.

3. Acceptance and the user's capacity

• By opening an account, signing in, or using the service in any way, the user accepts these terms in full. A user who does not accept them must not use the service.
• The user expressly declares that it uses the service in the course of its business, as a business and a taxpayer subject to fiscalization, and not as a consumer. Consumer protection rules do not apply to the relationship between the user and the provider.
• Whoever accepts these terms declares and warrants that they are authorised to bind the taxpayer they act for. The provider is under no duty to verify that authority and bears no consequence of its absence.
• Where a separate written contract or a separate accepted offer exists, these terms apply in addition to it. Sections 6, 7a, 13, 14 and 22 of these terms apply alongside a separate contract unless that contract expressly regulates the same matter differently; in case of conflict the separate contract prevails (article 142 of the Law on Obligations).

4. Approval status, environments and demo mode

Otkucaj is an approved element of electronic fiscalization with the Tax Administration of the Republic of Serbia. In the register of approved elements it is listed under the name "Otkucaj", record number 1667, version 1.3.6, classification 3 (advanced ESIR). The approval covers the ESIR only. Nothing on this site, in the application or in the documentation means that the local fiscal receipt processor (L-PFR) is approved; that is a separate element on a separate procedure.

Approval of the ESIR does not by itself make a user's receipts fiscal. A fiscal receipt comes into existence only when the ESIR works with a fiscal receipt processor and with the security element that the Tax Administration issues to the user, against that user's own PIB. A new account opens in demo mode: documents are then issued by a simulator built into Otkucaj, with no PFR and no connection to the Tax Administration. Those documents are not fiscal receipts and carry the notice "ОВО НИЈЕ ФИСКАЛНИ РАЧУН", which the Rulebook on types of fiscal receipts (article 2) prescribes for documents that do not count as fiscal receipts. As we understand it, receipts issued in the Tax Administration's test environment are not fiscal receipts either. Neither may be given to customers in place of a fiscal receipt or used in trade. Using demo mode or the test environment for actual trade is prohibited and is the user's sole responsibility.

The provider, as holder of the approval, maintains Otkucaj in line with the fiscalization regulations and the Tax Administration's technical guide, but does not guarantee that the approval will remain in force, or on what conditions. A withdrawal of the approval, and any change to the regulations, to the technical guide or to the Tax Administration's requirements, is not a breach of contract by the provider and gives the user no claim, unless the withdrawal was caused intentionally or by gross negligence of the provider, and may lead to a change in the service or to its permanent discontinuation, subject to sections 6 and 16.

Demo mode, the test environment, trial periods and any free use are provided as they are, with no warranty whatsoever, and may be changed, restricted or discontinued at any time, with no notice and with no reason given.

5. Accounts, access and API keys

• Accounts are opened by the provider at the user's request, at the provider's own discretion. The provider is under no duty to open an account, nor to explain a refusal.
• The user must keep their credentials safe, must not share them, and must not let third parties in. Every action carried out through the user's account counts as the user's own action.
• API keys are confidential. The user is responsible for every action carried out with their key, including actions carried out through a misuse of the key the user failed to prevent.
• The user must notify the provider of any suspected compromise of an account or a key without delay, and within 24 hours at the latest.
• The provider may temporarily restrict access for maintenance, security or regulatory compliance, with notice where that is possible.
• The user must keep their contact details accurate and up to date.

6. The provider's right to withhold, restrict or withdraw access

Access to Otkucaj is a personal, non-exclusive, non-transferable permission, revocable at any time, which the provider grants to the user. It is not an acquired, permanent or irrevocable right of the user.

The provider reserves the discretionary right, at any time, with immediate effect, without prior notice and with no obligation to state or explain a reason, to:

• suspend access for the user, or for an individual account, point of sale or API key;
• restrict the scope of the service, the number of accounts, points of sale, receipts or API calls;
• refuse to open an account, to reopen it, to renew it or to extend its use;
• permanently withdraw an account and unilaterally terminate the contractual relationship with the user.

The provider may exercise this right against the whole of the user's access or only a part of it, temporarily or permanently. The right does not depend on a reason existing, on that reason being well founded, or on the reason being communicated to the user. The provider is under no duty to explain the decision, to give advance notice, to allow a period for putting something right, or to entertain an objection to that decision.

For clarity, the following are examples of situations in which the provider ordinarily acts in this way, and this list in no way limits the discretionary right in the preceding paragraph: non-payment or late payment of fees; suspicion of misuse, fraud or use of the service for unlawful trade; use of demo mode for actual trade; endangering the security, stability or integrity of the system; loading the infrastructure beyond ordinary use; breach of any obligation under these terms; a request or an order from a competent authority; the termination or change of approval status with the Tax Administration; discontinuation of the service in whole or in a given market; and the provider's own free business judgement.

Exercising the right under this section is not a breach of contract by the provider and gives the user no right to: damages, lost profit, a refund or a proportionate reduction of fees paid, a contractual penalty, an extension of the term of use, or any other claim against the provider on that basis, except the provider's liability for intent or gross negligence, which under article 265 of the Law on Obligations cannot be excluded in advance. The user expressly waives those claims in advance, to the extent such a waiver is permitted by mandatory law.

The provider may cease providing the service as a whole, at any time. That includes shutting Otkucaj down as a product, ceasing maintenance, withdrawing or not filing an application for approval, ending the free plan, ceasing to operate in a market or for a group of users, and permanently closing every account. This is a purely commercial judgement by the provider, requires no reason and no explanation, and gives the user no right to damages, to lost profit, to a refund, or to any other claim, except the provider's liability for intent or gross negligence, which under article 265 of the Law on Obligations cannot be excluded in advance. In that case the provider will notify users in the manner set out in section 20 and allow the period in section 16 for retrieving data, which is its only obligation in connection with the discontinuation.

No provision of these terms, no statement, offer, price, announcement, the label "free", or the length of use so far, creates any right of the user to the service being permanent, to a particular volume, to a particular feature, or to any expectation that the service will be available in future. The user expressly confirms that it does not base its business on an assumption that Otkucaj is permanent and that it is itself responsible for a fallback arrangement in the event of discontinuation, in accordance with section 12.

The free plan is revocable in particular: the provider may at any time change its scope, introduce or change a limit on the number of receipts, start charging for what was free until then, or abolish the free plan entirely, by publishing under section 19. No user of the free plan has any right to keep the terms it found.

Suspension or withdrawal of access does not release the user from paying fees that fell due before the day it ends.

This section does not affect the handling of the user's data under section 16.

7. Permitted use and prohibited acts

The user may use the service only to record its own turnover, in accordance with the regulations and these terms. The following are prohibited in particular:

• misuse of the system, unauthorised access or attempted access to other people's data, and circumventing security mechanisms and limits;
• anything that endangers the operation, stability or availability of the service, including automated load, bulk data extraction and load testing without the provider's written consent;
• resale, rental, sublicensing, sharing access with third parties, or providing the service to third parties under the user's own name, without the provider's explicit written permission under section 7a;
• reverse engineering, decompilation, disassembly, copying, or creating derivative works from the service, except to the extent mandatory law expressly permits;
• using the service, its documentation or data about how it works in order to develop, improve or promote a competing product;
• removing or altering marks of authorship, name, version or fiscal status, and altering the appearance and content of receipts contrary to the regulations;
• entering unlawful, false or other people's content, and using the service to conceal turnover or evade tax obligations.

A breach of this section entitles the provider to suspend access immediately under section 6 and to full compensation.

7a. No resale without explicit permission

Otkucaj may not be resold, distributed or otherwise put on the market without the provider's explicit written permission. A user who does so breaches these terms, and anyone who in doing so copies Otkucaj, puts copies of it on the market or communicates it to the public without permission also, as we understand it, breaks the law.

In this section, Otkucaj means the service defined in section 2 and all software the provider publishes under the Otkucaj name, including Otkucaj Kasa, Otkucaj L-PFR, the mobile application, the installation packages and the documentation. Without the provider's explicit written permission it is prohibited in particular to:

• sell, resell, rent, lease, sublicense or transfer for payment Otkucaj, in whole or in part;
• sell or charge for accounts, access, API keys, points of sale, "licences", "activations" or "subscriptions" for Otkucaj;
• offer Otkucaj under another name or under one's own brand (white label), or present it as one's own product;
• charge for Otkucaj as part of a bundle with equipment (a till, a computer, a printer, a card reader) or with another service, so that the buyer also pays for Otkucaj itself;
• copy, publish or share Otkucaj's installation packages, source code or executable code;
• advertise or offer any of the above, even where no sale took place.

What permission is. Permission exists only if the provider has issued it in writing, expressly, to a named person, stating its scope, territory and term. Permission cannot be inferred from an oral arrangement, from silence or tolerance, from correspondence that does not expressly grant it, from a business relationship, from the free plan, from the length of use so far, or from someone being a user, a partner, a bookkeeper, a service technician or an equipment seller. The provider is under no duty to grant permission, nor to explain a refusal.

What is not resale. A taxpayer uses Otkucaj for its own turnover, and its bookkeeper, representative or employee may use it on that taxpayer's behalf, on that taxpayer's account (section 2). Helping a taxpayer open and set up its own account is not resale, as long as neither Otkucaj itself nor access to it is charged for. The "Otkucaj fiskalizacija" WooCommerce plugin is published under the GPLv2 licence, which governs the code of that plugin only: the plugin does not work without an account and an API key issued by the provider, and gives no right whatsoever to Otkucaj.

What the law says, as we understand it. Otkucaj is a computer program, and a computer program with its documentation is a copyright work (article 2 of the Law on Copyright and Related Rights). The copyright holder has the exclusive right to authorise or prohibit the reproduction of Otkucaj, the distribution and rental of copies of it, and its communication to the public (articles 20, 21, 22 and 30 of that law). Whoever does any of that without permission infringes those rights. The rights holder may then ask a court for a declaration of infringement, a prohibition of the infringing acts, destruction of unauthorised copies, damages and publication of the judgment (article 205 of that law). Unauthorised reproduction of a computer program and putting unauthorised copies on the market may also constitute the criminal offence of unauthorised exploitation of a copyright work under article 199 of the Criminal Code.

The Tax Administration's approval for Otkucaj was issued to the provider, who is its holder. Whoever resells Otkucaj without permission does not thereby become the holder of the approval, and may not offer Otkucaj as their own product or promise a buyer anything on the provider's behalf.

Consequences. In every case it discovers, the provider may, without notice and under section 6, permanently withdraw every account, point of sale and API key opened, used or offered as part of the resale, claim full compensation including the benefit gained from the resale, file a criminal complaint and bring proceedings before the competent court. A person who paid an unauthorised reseller for Otkucaj has no claim against the provider on that basis and pursues its rights against the reseller. The provider may offer that person continued use of Otkucaj directly, under these terms. The right to export data under section 16 is preserved.

Checking and reporting. Whoever claims to hold permission must show it on request. Anyone offered Otkucaj for payment may check through the contact form whether the seller holds permission, and report unauthorised resale the same way.

8. The user's obligations and the accuracy of data

• The user enters accurate taxpayer details (TIN, business name, point of sale, tax rates and labels) and is solely responsible for the accuracy, completeness and lawfulness of the data on the receipts.
• The user must issue receipts in accordance with the Law on Fiscalization and the regulations made under it, and must keep track of changes to them.
• The user must obtain and maintain: the security element, the PAC and access to the Tax Administration's system, a working L-PFR or, as the case may be, access to the V-PFR, computer equipment, a printer, an internet connection and antivirus protection. As we understand article 6 of the Law on Fiscalization, a taxpayer that uses the V-PFR must also ensure at least one device with its own PFR (an L-PFR) in each business premises, unless it sells at retail exclusively over the internet or sells only its own used movable assets.
• The user must check that the receipts issued are correct and report any irregularity without delay, and within 15 days of the day the irregularity could have been noticed at the latest. After that period the user loses the right to rely on that irregularity, unless it results from intent or gross negligence of the provider (article 265 of the Law on Obligations).
• The provider is not the user's tax adviser, bookkeeper or representative before the Tax Administration, and gives no tax or legal advice. Answers given through support are technical assistance only.

9. Plans, fees, payment and price changes

Otkucaj is offered in the following plans, whose scope and price are published on otkucaj.com:

• Free plan: every feature of the application and up to 500 fiscal receipts per calendar month per user. The provider accepts no support obligation whatsoever under this plan: questions are answered by the published manual, the guides and the API documentation, and the provider is not obliged to answer a message from a free plan user, or to do so within any period.
• Priority: 100 EUR per month, excluding tax, with no limit on the number of receipts and with priority support by e-mail. Support covers help using and connecting the application, and not the resolution of problems originating in equipment, the internet connection, the security element, the PFR or the Tax Administration's systems.
• By agreement: scope, conditions and price are set by a separate offer or contract.

• Passing the free plan. Exceeding the number of receipts included in the free plan is a ground for moving to a paid plan. The provider notifies the user in the application and allows a period to respond. If the user does not respond within that period, or does not accept the offer, the provider may without further notice restrict the scope of the service, suspend access or close the account, in accordance with section 6, while the user's right to export data under section 16 remains intact. The provider undertakes no obligation to provide the service beyond the limits of the free plan, or to provide it in any scope free of charge.
• Fees are payable in advance, by the date stated on the invoice. On late payment the provider is entitled to statutory default interest and to suspend access without notice, and such suspension does not postpone the due date of the claim.
• The provider may change prices, the scope and the contents of plans, including the number of receipts included in the free plan, by publishing on otkucaj.com or notifying in the application, at least 15 days before they take effect. Continuing to use the service after that date counts as acceptance of the change. A user who does not accept it may stop using the service before that date.
• Fees paid are not refunded, in whole or in part, if use ends for any reason, including suspension and withdrawal of access under section 6 and discontinuation of the service as a whole, unless the end of use results from intent or gross negligence of the provider (article 265 of the Law on Obligations).
• All prices are stated exclusive of tax unless stated otherwise. Public levies, bank charges and payment transaction costs are borne by the user.
• The provider is entitled to set its claims off against the user's claims.

10. Intellectual property and the licence

The service, its source and executable code, the database, the design, the documentation, the logo and accompanying material are protected by copyright and related rights law. These terms transfer no right in them to the user, nor any right to use the names "Откуцај" and "Otkucaj" or the domain otkucaj.com.

The user is granted a non-exclusive, non-transferable, non-sublicensable and revocable licence to use the service for its own business purposes, only for the duration of the contractual relationship and only to the extent paid for. The licence does not include any right to resell, distribute or sublicense, which can be acquired only by explicit written permission under section 7a. The licence ends the moment access ends, with no separate declaration needed.

If the user sends the provider a suggestion, a comment or an idea for improving the service, the provider may use it freely and permanently, without payment and without attribution, and the user acquires no right on that basis.

The user keeps the rights to its own data entered into the service and grants the provider the right to process, store, transmit to the PFR and SUF, and display that data, to the extent needed to provide the service and to comply with legal obligations.

11. Availability, maintenance and changes

• The provider does not guarantee uninterrupted availability and undertakes no service level (SLA) unless a service level has been separately agreed in writing.
• The provider may carry out planned maintenance, and urgent security work without notice.
• The provider may at any time change, improve, merge, restrict or remove individual features, change the technical requirements for use, and change the infrastructure, including suppliers.
• The provider may discontinue the service in its entirety, by publishing that on otkucaj.com, and in the cases in section 6 without notice.
• The service depends on third party systems (the internet provider, hosting, Cloudflare, the L-PFR device, the V-PFR, the Tax Administration's SUF). Their unavailability is not a defect in the service.

12. The user's business continuity

The user must, in accordance with the fiscalization regulations, arrange its own way of recording turnover while the service is unavailable, including a fallback solution and a procedure for a loss of connection. The risk of an interruption to the user's business caused by the service being unavailable, for any reason, including suspension or withdrawal of access under section 6, is borne solely by the user. The user must regularly download and keep its own reports and records.

13. Liability and its limits

The service is provided "as is" and "as available". The provider gives no express or implied warranty that the service fits the user's particular purpose, that it will run without interruption or error, as to business results achieved, or that regulations, technical guides and third party systems will stay unchanged.

The provider is responsible for the Otkucaj ESIR forming and forwarding requests to the PFR correctly, in line with the Tax Administration's technical guide in force.

The provider is not responsible in particular for:

• interruptions and errors originating with third parties (the internet provider, the electricity grid, hosting, Cloudflare, the L-PFR device, the V-PFR, the Tax Administration's SUF, the bank, the printer and its drivers);
• loss caused by the user entering incorrect, incomplete or late data, nor for the content of the receipts;
• tax liabilities, interest, fines, misdemeanour and other penalties imposed on the user, nor for measures taken against the user by the authorities;
• loss or alteration of data caused by the acts of the user, its employees, or persons the user let in;
• the consequences of credentials or API keys being compromised on the user's side;
• third party software and integrations the user connects to the API itself;
• the consequences of access being suspended or withdrawn under section 6.

Except in the case in the last paragraph of this section, the provider is not liable for indirect loss, lost profit, lost turnover, loss of data, loss from business interruption, loss of a business opportunity, of reputation or of expected savings, whatever the basis of liability and whether or not it was warned that such loss was possible.

The provider's total liability across all claims together is limited to the fees the user actually paid for the service in the three months preceding the event that caused the loss, and to no more than 30,000 dinars. Where the service was not charged for, or was used in demo, trial or free mode, the provider's liability is excluded to the extent mandatory law permits.

The limits in this section do not apply to loss caused intentionally or by gross negligence, to the extent they cannot be excluded under mandatory law.

14. Indemnity

The user must reimburse the provider for every loss, cost, fine, levy and legal representation cost arising from a third party claim or a procedure before an authority which results from: data the user entered into the service, turnover the user recorded or failed to record, a breach of these terms, a breach of fiscalization, tax or data protection regulations, or use of the service contrary to its purpose. The provider will inform the user of such a claim and is entitled to choose its own legal representative.

15. Force majeure

The provider is not liable for failure or delay in performance caused by circumstances beyond its reasonable control, including: an interruption of electricity or of the internet, a supplier infrastructure failure, a cyber attack including DDoS, the unavailability or alteration of the Tax Administration's systems, a change in the regulations, an act of an authority, a strike, an epidemic, a natural disaster, war and civil unrest.

16. Data, export and deletion after termination

The processing of personal data is governed by the Privacy policy.

Data on the fiscal receipts the user issued through Otkucaj is delivered to the Tax Administration through the PFR, as a rule at the moment of issue and, where no internet connection is available, within five days at the latest (article 8 of the Law on Fiscalization). The Tax Administration holds that data independently of Otkucaj and whatever the reason access ended. Whether and in what form the user can see it through the Tax Administration's systems depends on the Tax Administration, so the user downloads and keeps its own reports and records itself (section 12).

In addition, within 30 days of the day access ends, the user may request an export of its data from Otkucaj in a machine readable form, in writing through the contact form. The provider will meet such a request within a reasonable time. After that period the provider may permanently delete the user's data, except the data in the next paragraph, without separate notice.

The provider keeps data on billing for the service for the periods that accounting and tax regulations impose on it. The retention periods for the user's own accounting documents and business books are the user's to meet, and the user downloads and keeps its own records (section 12).

17. Confidentiality

Each party must keep confidential the other party's non-public information it learns through the use of the service, including technical solutions, prices, credentials and security information. The obligation survives the end of the contractual relationship. It does not apply to information that is public without a breach of these terms, or whose disclosure is required by law or by a competent authority.

18. Duration, termination and its effects

• The contractual relationship lasts as long as access does. The user may stop using the service at any time, through the contact form; fees already due remain owed, and fees paid are not refunded.
• The provider may also bring it to an end under section 6, at any time and with no reason given.
• When access ends, every licence granted to the user ends. Sections 7a, 8, 9, 10, 13, 14, 16, 17, 21 and 22 survive termination.

19. Changes to these terms

The provider may change these terms. Changes are published on this page and take effect on the date stated at the top of it, and for existing users no earlier than 8 days after publication, except changes made because of a change in the regulations, an order from an authority or a security need, which take effect at once. Continuing to use the service after they take effect counts as acceptance. The user should check this page from time to time.

20. Notices

A notice from the provider counts as duly delivered to the user when it is published on this page, shown in the application, or sent to the contact details the user gave. The user sends notices to the provider at [email protected], through the contact form or by post to the registered seat given in section 1.

21. Assignment, severability, waiver and entire agreement

• The provider may transfer its rights and obligations under this relationship to a legal successor or an affiliated party, without the user's consent. The user may not transfer its rights and obligations without the provider's prior written consent.
• If any provision of these terms proves void or unenforceable, the rest stay in force, and the void provision is replaced by the permitted provision closest to its purpose.
• The provider's failure to exercise a right on one occasion is not a waiver of that right, on that occasion or in the future.
• These terms, together with the Privacy policy, the price list and any separate contract, are the entire agreement and replace every earlier oral or written understanding on the same subject.
• Section headings are for ease of reference only and do not affect interpretation.
• The Serbian version of these terms prevails. Versions in other languages are provided for ease of reading.

22. Governing law and jurisdiction

These terms are governed by the law of the Republic of Serbia, excluding its conflict of laws rules. The court with subject matter jurisdiction over the provider's registered seat has exclusive jurisdiction over all disputes. The parties will try to settle a dispute by agreement, but that is not a precondition for bringing proceedings.

23. Contact

Saša Mihajlović pr Računovodstveni poslovi TEFIS Vlasotince, details in section 1.
[email protected], the contact form, or by post to the registered seat given in section 1.