Translation for information only. The German version is legally binding.
General terms and conditions for the Gesello app and the purchase of Gesello Pro.
1. Scope
These terms apply to the use of the Gesello app (installed app and web version) and to the purchase of Gesello Pro. The provider is Clemens Riemer, Schulstraße 2, 47918 Sankt Tönis, Germany, email dev@gesello.app.
If you buy through your device’s store, the terms of that store also apply to payment, billing and refunds.
2. Services
Gesello is a digital technical handbook with calculators, sketches and explanations for technical trades. The basic modules are free.
Gesello Pro is a one-time purchase without a subscription. It unlocks the modules and functions marked “Pro” in the app for the store account used to make the purchase.
Which modules and functions belong to Gesello Pro is determined by the description in the store and on gesello.app at the time of purchase.
3. Conclusion of contract and payment
The purchase of Gesello Pro is concluded through the purchase process in your device’s store. Payment and invoicing are handled exclusively by the store. The price is shown in the store before you buy.
4. Further development and changes
Gesello is developed continuously. Modules and functions may be added, revised, merged, renamed, moved, or removed in part or in full. Reasons include new technical findings, changes to standards or the legal situation, third-party rights, security, or technical requirements of the operating systems and stores.
Such changes are no reason for a refund of the purchase price, provided that Gesello Pro as a whole keeps its essential benefit and you incur no additional costs. We announce significant changes in the app or on gesello.app.
Mandatory consumer rights remain unaffected. This applies in particular to the statutory right to terminate the contract if a change impairs access to Gesello Pro or its usability more than insignificantly.
5. Right of use
You receive a simple, non-transferable right to use Gesello for your own purposes, both professionally and privately. Content, sketches and calculation steps may not be systematically copied, redistributed or incorporated into other products.
Licences for schools and companies with several devices are agreed separately.
6. Guide values and responsibility
The values and calculations are prepared with great care. Guide values are marked as such. Gesello does not replace a drawing, work instruction, manufacturer’s specification or applicable standard. Check results before you manufacture or assemble based on them, especially for safety-relevant parts.
7. Liability
We are liable without limitation for intent and gross negligence, for injury to life, body or health, and under the German Product Liability Act.
In the case of slight negligence, we are liable only if an obligation is breached whose fulfilment is essential for the proper use and on which you may rely (material contractual obligation). Liability is then limited to the typical, foreseeable damage. Otherwise, liability for slight negligence is excluded.
The statutory rights in the event of defects in digital products remain unaffected.
8. Withdrawal and refunds
For purchases through your device’s store, the withdrawal and refund rules of that store apply. For digital content, the right of withdrawal may expire as soon as the unlocking begins with your consent. You request refunds directly from the store.
9. Data protection
How we handle data is described in the privacy policy. In short, there is no account, no advertising and no tracking. Settings, favourites and history stay on your device.
10. Final provisions
German law applies. If you are a consumer, the mandatory protective provisions of the country in which you live remain unaffected.
We are neither willing nor obliged to take part in dispute resolution proceedings before a consumer arbitration board.
If any provision is invalid, the remaining provisions remain valid.
Last updated
October 2026