Last updated: August 7, 2026
These General Terms and Conditions (hereinafter "GTC") govern the contractual relationship between you (hereinafter "User") and
One Tree Hill GmbH
Oppenheimer Landstr. 70
60596 Frankfurt am Main
Managing Director: Werner Märkl
Commercial Register: HRB 81584, Local Court of Frankfurt am Main
VAT ID: DE217325183
Email: info@tennisflow.app
(hereinafter "Provider", "we", or "us")
regarding the use of the mobile application "TennisFlow" (hereinafter "App") and the corresponding website tennisflow.app (hereinafter "Website").
TennisFlow is an AI-powered app for analyzing tennis swings and movements. The App allows users to record videos of their play and have them evaluated using machine learning to receive technical feedback and suggestions for improvement.
These GTC apply to all versions of the App (free and paid versions) and all services offered via the App or Website. These GTC are incorporated as part of the contract formation process prescribed by law.
These GTC are directed at consumers habitually resident in the selected EU countries Germany, Austria, France, the Netherlands, Spain, Italy, Portugal, and Sweden and, as a separate non-EU territory, Switzerland. Mandatory country-specific provisions are set out in particular in § 9.
The use of TennisFlow requires the User to be at least 13 years old. Users under 18 years of age require the consent of a legal guardian for use and registration.
The use of TennisFlow is at the User's own risk. A prerequisite for use is that the User is in good general health. Specifically:
The analyses, tips, and workout recommendations provided by TennisFlow do not constitute medical advice and are not a substitute for a medical examination or sports physiotherapy treatment.
The extent of available features depends on whether the User uses the free version (FREE) or a paid version (PRO). The free version provides access to selected basic features. Advanced features are available via subscription (PRO).
Paid monthly and annual subscriptions are distributed exclusively through the Apple App Store. The subscription model, term, and final price displayed there for the User's country or region before purchase confirmation are decisive. Prices shown on the Website are for general guidance only.
Apple processes the order, payment, and invoicing. Whether and how VAT or other statutory charges are included in or shown with the final price is governed by applicable law and the presentation in the Apple App Store.
Full use of TennisFlow may require additional equipment to be provided by the User at their own expense. This includes in particular:
This equipment is not part of the TennisFlow services and must be procured by the User at their own expense.
The use of TennisFlow requires the User to set up their smartphone near the tennis court – e.g., using a tripod, ball can with a rubber band, or another suitable mount. The User is solely responsible for ensuring that the setup is secure and stable.
⚠️ Warning: Ensure that the smartphone and mount are positioned in a way that neither you nor other players, spectators, or passersby can trip over them, run into them, or collide with them. Ensure that the setup is stable and the device cannot tip over or fall down.
The User acknowledges that setting up a smartphone, tripod, or other mount at the edge of the court may pose a risk of injury – especially from tripping, rolling an ankle, or colliding with or knocking over the equipment. The User bears full responsibility for safe positioning and is liable for damages and injuries resulting from improper setup.
To the extent permitted by law and subject to § 10, the Provider is not liable for damage, loss, or destruction of the User's smartphone, tripod, mount, or other equipment occurring in connection with the use of TennisFlow. This specifically includes damages caused by:
TennisFlow uses artificial intelligence (including large language models such as Google Gemini) to generate technique analyses and workout recommendations. The User acknowledges:
⚠️ Warning: Only perform exercises and movements that match your fitness level and health condition. The Provider is liable for injuries resulting from following AI-generated workout recommendations only to the extent mandatorily required by law and subject to § 10.
The User is solely responsible for ensuring that applicable legal regulations are observed when making video recordings on and around the tennis court. This specifically entails:
To the extent permitted by law and where the User is responsible for the infringement, the User indemnifies the Provider against substantiated third-party claims based on unlawful use of the video function, infringement of personality, data protection, or other third-party rights, or a culpable breach of the safe-setup obligations (§§ 4.1 and 4.2). The indemnity includes reasonable statutory legal-defense costs. Mandatory liability, personal injury, product liability, and statutory consumer rights remain unaffected.
The video recordings remain exclusively on the User's device. No videos are transmitted to servers of the Provider or third parties. Further details can be found in our Privacy Policy.
The use of TennisFlow requires the creation of a user account. The User is obligated to provide truthful information and protect their account from unauthorized access.
When using the App for the first time, the User will be asked to read and accept these GTC as well as the Privacy Policy. Without acceptance, the use of the App is not possible.
Paid monthly and annual subscriptions can be concluded exclusively in the Apple App Store. The purchase is concluded upon confirmation after the steps displayed in the Apple App Store. Apple processes the order, payment, and purchase-related declarations; Apple's terms also apply. The Provider supplies the App services. Mandatory consumer rights remain unaffected.
The user agreement for the free version is concluded for an indefinite period. PRO is offered as a monthly or annual subscription. The subscription automatically renews for the period displayed in the Apple App Store before purchase unless canceled within the deadline shown there. Apple displays the duration, price, and renewal terms before purchase confirmation.
The subscription is managed and canceled in Apple's subscription management, for example under “Settings” > Apple Account > “Subscriptions.” Uninstalling the App or deleting the TennisFlow account does not cancel the Apple subscription. The free user account can be deleted at any time. More favorable or mandatory statutory termination rights, including those in § 9, remain unaffected.
The right of both parties to terminate without notice for good cause remains unaffected. A good cause exists in particular if the User repeatedly or seriously violates these GTC.
Refund and withdrawal requests for subscriptions purchased in the Apple App Store must be submitted to Apple via reportaproblem.apple.com. Apple reviews and processes them under the applicable rules. This does not limit any mandatory statutory claims the consumer may have against the Provider.
Consumers in Germany, Austria, France, the Netherlands, Spain, Italy, Portugal, and Sweden generally have a statutory right of withdrawal for 14 days from conclusion of a distance contract unless a statutory exception applies. Because paid subscriptions are distributed exclusively through the Apple App Store, Apple processes the purchase and the withdrawal declaration. The declaration must be submitted via reportaproblem.apple.com using the steps provided there.
For a contract to supply digital content not supplied on a tangible medium, the right of withdrawal may expire before the end of the 14-day period only if performance has begun after the consumer expressly consented to early performance, acknowledged the resulting loss of the right of withdrawal, and received the contract confirmation required by law. The required declarations are obtained in the Apple purchase process where applicable.
For digital services, the mere commencement of performance does not automatically cause the immediate loss of the right of withdrawal. If the consumer expressly requested performance during the withdrawal period, a legally permissible proportionate amount for services supplied up to withdrawal may be payable. The right expires upon full performance only if the express consent and acknowledgment required by law have been given. Apple obtains purchase-related declarations where applicable.
Apple processes reversal and refunds for App Store purchases. Mandatory statutory claims against the Provider remain unaffected. Swiss law does not provide a general statutory right of withdrawal for distance contracts; Apple's voluntary refund policies and mandatory Swiss rights remain unaffected.
For consumers habitually resident in Germany, Austria, France, the Netherlands, Spain, Italy, Portugal, or Sweden, the mandatory protective provisions of their country of residence remain unaffected. This applies in particular to the respective national implementations of Directive (EU) 2019/770 on digital content and digital services. The App and necessary updates must be supplied in conformity with the contract for the period required by law. In the event of non-conformity, remedies under applicable law include bringing the service into conformity and, where the statutory conditions are met, a price reduction or termination and refund. Changes to the digital service are made only for an objectively justified reason provided for in the contract and without additional cost. Where a change has more than a minor adverse impact, the statutory advance notice on a durable medium and the statutory right to terminate free of charge apply unless access to the unchanged service is maintained. The 14-day principle in § 8 remains unaffected.
Mandatory provisions of the German Civil Code (BGB) and German consumer law remain unaffected.
Mandatory rights under the KSchG and FAGG remain unaffected. Mandatory reminder rights concerning automatic contract renewal remain in place where applicable; Apple manages the subscription.
The French version and contractual information required by law will be provided to French consumers in the relevant purchase process. Mandatory rights under the Code de la consommation, including statutory conformity rights, remain unaffected. Where Article L215-1 of the Code de la consommation applies, the consumer is informed in a prominent manner, between three months and one month before the end of the period for rejecting renewal, of the upcoming renewal and the final date for non-renewal. If a legally required notice is not provided, the consumer may terminate free of charge at any time after renewal; advance payments refundable by law will be reimbursed within 30 days. Where applicable, electronic termination must be possible through the online channel used to conclude the contract; Apple subscriptions are canceled through Apple's subscription management. Consumers may use the free consumer mediation identified in § 13.
An English version is provided for the Netherlands. Mandatory Dutch information, transparency, and consumer rights remain unaffected. After an initially agreed fixed term expires, a subscription covered by the relevant law continues only for an indefinite period. The consumer may terminate that continuation at any time with no more than one month's notice. Fees prepaid for a later period will be refunded pro rata from the effective date of termination as required by mandatory Dutch law; more favorable rights remain unaffected.
The Spanish version and contractual information required by law will be provided to Spanish consumers in the relevant purchase process. Mandatory rights under Real Decreto Legislativo 1/2007 and other Spanish consumer law remain unaffected. Termination is available through the same electronic channel used to conclude the subscription, in particular through Apple's subscription management. It may not be obstructed by disproportionate barriers, does not incur a contractual penalty, and generally takes effect at the end of the already paid period; more favorable statutory rights remain unaffected.
The Italian version and contractual information required by law will be provided to Italian consumers in the relevant purchase process. Mandatory rights under the Codice del Consumo remain unaffected. Duration, automatic renewal, and termination are clearly disclosed under §§ 3, 6, and 7 and in the Apple purchase process. For fixed-term service contracts with automatic renewal, the consumer is notified under Article 65-bis of the Codice del Consumo 30 days before expiry, in writing, by SMS, or through an electronic communication method designated by the consumer, of the deadline for non-renewal. If that notice is not given, the consumer may terminate free of charge at any time until the next contractual expiry date. Where Italian law requires separate express approval of individual clauses, that approval is obtained separately; a blanket acceptance of these GTC does not replace it.
The Portuguese version and contractual information required by law will be provided to Portuguese consumers in the relevant purchase process. Mandatory rights under Law No. 24/96 of 31 July (Consumer Protection Act), Decree-Law No. 24/2014 (distance and off-premises contracts), Decree-Law No. 84/2021 (conformity of goods and of digital content and services), and the legal regime on standard contractual terms (Decree-Law No. 446/85, as amended) remain unaffected. Duration, automatic renewal, and termination are clearly disclosed under §§ 3, 6, and 7 and in the Apple purchase process. Under Portuguese law, standard terms that impose automatic renewal by silence are prohibited where the deadline for expressing an opposite intention is excessively remote from the end of the contract. Apple subscriptions are canceled through Apple's subscription management and must not be obstructed by disproportionate barriers; more favorable statutory rights remain unaffected.
An English version is provided for Sweden; mandatory information and language requirements and mandatory Swedish consumer law remain unaffected. Where required by law, the consumer will receive a written reminder no later than one month before the final termination date for an automatic renewal. Statutory exceptions, including for renewals of no more than three months, remain unaffected. If a legally required reminder is not given, the consumer has the immediate termination right provided by law.
For consumers in Switzerland, mandatory rights under the Swiss Code of Obligations (OR), the Federal Act Against Unfair Competition (UWG), the revised Data Protection Act (nDSG), and other Swiss law remain unaffected. A general statutory EU distance-contract withdrawal right does not apply; § 8.4 governs.
The User remains responsible for using TennisFlow, including its analyses, workout suggestions, and recommendations. Liability limitations in these GTC apply only to the extent permitted by law.
For free services, the Provider is liable, to the extent permitted by law, only for intent and gross negligence. For paid services, the Provider is liable without limitation for intent and gross negligence; for a slightly negligent breach of an essential contractual obligation, liability is limited to foreseeable damage typical for the contract. Otherwise, liability is excluded to the extent permitted by law.
Any mandatory statutory liability remains unaffected, including liability for injury to life, body, or health, claims under the applicable product liability rules in the EU and Switzerland, an assumed guarantee, fraudulent concealment, and statutory consumer rights.
Subject to the preceding paragraphs and only to the extent permitted by law, liability for damage to the User's equipment, consequences of unsafe setup, and consequences of unsuitable or improperly performed AI workout recommendations is excluded or limited to foreseeable damage typical for the contract. § 10.3 remains unaffected.
The Provider does not guarantee any particular sporting success. Results depend in particular on physical condition, training intensity, and regularity.
All content provided in the App and on the Website (texts, graphics, logos, animations, software) is protected by the applicable intellectual-property laws. The User receives a simple, non-transferable right of use for personal, non-commercial purposes. Reproduction, distribution, or making available to the public is not permitted without the Provider's prior written consent unless mandatory law permits otherwise.
The protection of your personal data is important to us. Details about processing are available in our Privacy Policy. Mandatory data-protection rights under the GDPR, national EU provisions, and the Swiss nDSG remain unaffected.
Consumers are requested first to send their complaint directly to info@tennisflow.app so that a direct solution can be attempted.
The Provider is willing to participate in dispute resolution proceedings before the following consumer arbitration body:
Universalschlichtungsstelle des Bundes
Zentrum für Schlichtung e.V.
Straßburger Straße 8
77694 Kehl am Rhein
Germany
Email: mail@universalschlichtungsstelle.de
Website: https://www.universalschlichtungsstelle.de/
Consumers in France may also contact the above dispute resolution body after an unsuccessful direct attempt to resolve the complaint. Mandatory national rights of access to other competent bodies remain unaffected.
The Provider may modify these GTC with future effect where necessary because of legal, regulatory, or technical developments and reasonable taking the User's interests into account. The User will generally be informed by email or in-app notice at least two weeks before the intended effective date. Changes become part of the contract only by express consent or another statutory basis. Mandatory information, consent, termination, and consumer rights remain unaffected.
German law applies to the exclusion of the UN Convention on Contracts for the International Sale of Goods (CISG). Under Article 6(2) of the Rome I Regulation, this choice of law does not deprive EU consumers of the protection of mandatory provisions of the law of their country of habitual residence. For consumers in Switzerland, mandatory Swiss protective provisions under the applicable conflict-of-laws rules remain unaffected.
Jurisdiction is determined exclusively by mandatory statutory rules. These GTC do not create any additional or exclusive jurisdiction at the Provider's registered office for consumers.
Should individual provisions of these GTC be or become invalid in whole or in part, the validity of the remaining provisions shall not be affected.
Note: You can view these GTC at any time on our website at tennisflow.app/legal/termsg1/en/. If you have any questions, please contact info@tennisflow.app.