Terms of Use

Last updated: 15 October 2026

1. About these terms

These terms apply to the website trollsoftworks.com and the web application TrollFit. Both are provided by Šimon Svoboda, a private individual from the Czech Republic, who publishes software under the name Troll Softworks (“we”, “us”). By creating an account, signing in or otherwise using TrollFit you agree to these terms. If you don’t agree, please don’t use it.

2. Free beta by invitation

TrollFit is currently provided free of charge as a beta. It is under active development: features may change, be added or removed, and you may come across bugs — reports to info@trollsoftworks.com are very welcome.

For now the beta is by invitation. If you would like to try TrollFit, ask for an account number by email. We decide at our discretion whom we give a number to — mainly students, teachers and researchers — and there is no claim to receiving one. We may stop giving out new numbers, or open sign-up to everyone, at any time.

After the beta, TrollFit is planned to become a paid subscription service. We will announce this on this website and in TrollFit well in advance, together with the prices and terms. A free account never turns into a paid one on its own — you will only ever pay if you explicitly choose a paid plan, under terms shown to you at that time.

3. Your account

Using TrollFit requires a free account. An account is a 16-digit account number that we generate for you; the account itself stores no email or name. During the beta by invitation we send the number to you by email. You must be at least 16 years old to create one.

Your account number is the only key to your account. Keep it private — anyone who knows it can use your account. We store only a one-way fingerprint of it, so a lost number cannot be recovered or replaced; during the free beta you can ask us for a new one. An account is personal — please don’t share it or publish it.

You can delete your account at any time on the account page. We may block or delete an account that is used to attack or overload the service, to get around its access controls, for automated mass use, if its number has been published, or for anything unlawful.

4. Your data and results are yours

Your data is processed in your browser and stays on your device (see the Privacy Policy). We claim no rights to the data you analyse or to the results, fits, tables and figures you create with TrollFit. You are free to use them for any purpose — in publications, theses, teaching, reports and commercial work — without asking or attributing. (A mention that TrollFit helped is always appreciated, but never required.)

5. Your licence to use TrollFit

TrollFit — its code, design, texts and graphics — is © Šimon Svoboda, all rights reserved. We give you a personal, non-exclusive, non-transferable licence to use TrollFit for any lawful purpose, including study, research, teaching and work. You may not:

• copy, modify, redistribute, sell, rent or host TrollFit or any part of its code,
• remove or alter copyright notices,
• reverse-engineer it, except where the law expressly allows this,
• get around sign-in or other access controls, or
• use its code to build a competing product.

TrollFit includes open-source components that remain under their own licences — see Open-source licences.

6. Intended use — check your results

TrollFit is a tool for analysing and visualising data in research, teaching, studies and technical work. Its results — fitted parameters, uncertainties, bands, predictions, tests and figures — are statistical estimates. They depend on the data you enter, the model and settings you choose and on assumptions (for example about the uncertainties of your data) that only you can judge. TrollFit does not give professional, engineering, medical or legal advice.

TrollFit’s numerical methods are carefully tested, including against established reference implementations such as SciPy. Still, no software is free of errors. You are responsible for checking that results are correct and suitable for your purpose before you rely on them, for example by an independent calculation, a second method or software validated for that purpose.

TrollFit is not designed, tested, validated or certified for safety-critical or regulated use — that is, any use where an error or an inaccurate result could lead to death, injury, or serious damage to property or the environment. This includes in particular the design, operation, testing or certification of aircraft, vehicles, ships, railways, nuclear or chemical installations, medical devices, the diagnosis or treatment of people or animals, load-bearing structures, safety systems and weapons, and decisions that require validated software under laws or standards. TrollFit must not be used as the basis, or as a part of the basis, for such uses. If you use it that way anyway, you do so entirely at your own risk and outside the purpose for which TrollFit is intended.

7. No warranty

TrollFit is provided “as is” and “as available”. To the extent permitted by law, we give no warranties, express or implied — including that it will be error-free, uninterrupted, that its results will be accurate, or that it will be fit for a particular purpose. We may change, suspend or discontinue TrollFit; if we plan to discontinue it, we will try to announce this in advance. Your work is stored on your own device and can be exported at any time.

8. Limitation of liability

TrollFit is provided free of charge. To the maximum extent permitted by law, we are not liable for any damage resulting from the use of, or inability to use, TrollFit or its results — in particular indirect or consequential damage, lost profits, lost data, or damage caused by relying on results that you did not check, or by using TrollFit contrary to section 6.

If you use TrollFit in the course of a business or profession, our total liability towards you for all claims together is limited, to the extent permitted by law, to the amount you paid us for TrollFit in the twelve months before the event that caused the damage (during the free beta, this amount is zero). You are responsible for using TrollFit’s results in your work appropriately, and if a third party makes a claim against us because you used TrollFit or its results contrary to these terms, you will compensate us for the resulting damage and reasonable costs.

Nothing in these terms limits liability for damage caused intentionally or through gross negligence, for harm to life or health caused by us, or any other liability that cannot be limited under Czech law or the mandatory consumer-protection law of your country.

9. Changes

We may update these terms, for example when new features or paid plans are introduced. We will update the date at the top and announce significant changes on this website and in TrollFit at least 14 days before they take effect. If you don’t agree with the new terms, you can stop using TrollFit and delete your account.

If Troll Softworks becomes a company, TrollFit and these terms may be transferred to it. We will announce this in advance; your rights under these terms stay the same.

10. Governing law

These terms are governed by the law of the Czech Republic. If you are a consumer, you keep the protection of the mandatory laws of the country where you live. Disputes are decided by the courts of the Czech Republic, without prejudice to any right you have as a consumer to go to the courts of your own country.

11. Contact

Šimon Svoboda (Troll Softworks), Czech Republic
Personal contact: simon.svoboda@trollsoftworks.com
General enquiries and support: info@trollsoftworks.com