Terms and Conditions
Last updated: November 2026
This is an English translation of the German Allgemeine Geschäftsbedingungen. The German version is legally binding.
1. Scope
1.1 These General Terms and Conditions (Terms) apply to all contracts between Edwin von Lemberg, Rollbühlstraße 89, 68309 Mannheim, Germany (the “Provider”), and his clients (the “Client”) for the concept, design, development, publication and operation of learning apps (web app, iOS and Android) as well as related websites and additional services.
1.2 Clients can be consumers (Section 13 BGB) or businesses (Section 14 BGB), for example self-employed people, language schools and other educational institutions. Where a provision applies to only one of these groups, this is stated expressly.
1.3 Deviating terms of the Client apply only if the Provider expressly agrees to them in text form. Individual agreements in the offer take precedence over these Terms.
2. Conclusion of contract
2.1 The presentation of services and packages on edwinvonlemberg.com is not a binding offer. It describes the typical scope of services.
2.2 After the free, non-binding intro call, the Client receives an offer in text form, for example by email or as a PDF. It sets out the scope, the package, the price (for consumers including VAT), the payment plan and the expected schedule.
2.3 The contract is concluded when the Client accepts the offer in text form within the period stated in it, for example by email, or signs it.
2.4 The contract language is German. On request, the contract can be concluded in English. The Provider stores the contract text and sends it to the Client in text form together with these Terms.
3. Process and services
3.1 Prototype. After the contract is concluded and the first instalment of 25% of the package price (prototype fee) has been paid, the Provider builds a clickable prototype in the Client’s design, usually within two to three weeks. One feedback round on the prototype is included.
3.2 Decision after the prototype. From the time the prototype is provided, the Client has 14 days to declare in text form whether the project will continue.
- If the Client decides to continue, the Provider completes the app. The prototype fee is credited in full against the package price.
- If the Client decides not to continue, the contract ends. The Provider refunds the prototype fee in full, without the Client having to give reasons, within 14 days. In this case the prototype remains with the Provider. The Provider returns or deletes the Client’s content and materials.
- If the Client does not make a declaration within the period, the Provider sends a reminder in text form and sets a further period of seven days. If the Client still does not make a declaration, the contract ends as if the Client had decided not to continue.
This exit right applies in addition to the statutory right of withdrawal for consumers (section 12).
3.3 Development. The Provider develops the app step by step and usually provides a new version to try out every two weeks. Before launch, the Client receives a complete test version.
3.4 Publication. Depending on the package, the app is provided as a web app and submitted to the Apple App Store and Google Play. Store publication usually takes place via the Client’s own developer accounts, whose fees are paid by the Client unless agreed otherwise. Apple and Google decide on approval. If they require changes, the Provider makes them within the agreed scope. The Provider is not responsible for decisions of the store operators.
3.5 Revisions after launch. In the first three months after launch, three revisions based on the Client’s feedback are included. A revision is a bundled adjustment of existing features, texts or design. New features are not included. On request, the Provider develops them at a fixed price under a separate offer or on a time basis (section 6.5).
3.6 Exam formats and learning content. Exercises may be modelled on official exam formats. The Provider is not affiliated with any examination institute. No particular learning or exam success is owed. The Client is responsible for the accuracy of the content the Client supplies.
3.7 AI features. Optional features such as AI correction or a read-aloud voice use third-party services. Their results may contain errors and do not replace review by a teacher. Usage is included in operation up to a limit set out in the offer.
3.8 The Provider may use carefully selected subcontractors and third-party services for individual services, for example for hosting. The Provider remains responsible to the Client for the service.
4. Client cooperation
4.1 The Client provides the content needed for the project, for example texts, exercises, images and logos, in good time and in a usable form, and gives feedback within the agreed periods.
4.2 The Client warrants holding the necessary rights to the content supplied and that it does not infringe third-party rights. If the Client is responsible for an infringement, the Client indemnifies the Provider against resulting third-party claims.
4.3 If the project is delayed because the Client’s cooperation is missing, agreed dates are postponed accordingly. If the project is on hold for this reason for more than eight weeks, the Provider may invoice the services rendered so far after giving notice in text form.
5. Acceptance
5.1 Developing the app is a contract for work (Werkvertrag). Once the launch version is complete, the Provider asks the Client to accept it. The Client checks the launch version within 14 days and reports defects in text form.
5.2 Acceptance may not be refused because of insignificant defects. The launch version is deemed accepted if the Client does not refuse acceptance within the period, stating at least one defect. For consumers, this applies only if the Provider pointed out this consequence in text form together with the request for acceptance (Section 640 (2) BGB).
6. Prices and payment
6.1 The prices agreed in the offer apply. Prices on the website are net prices plus statutory VAT. Offers to consumers state the total price including VAT.
6.2 Depending on the agreement in the offer, the package price is paid as follows:
- In full: 25% at the start for the prototype, 50% when the test version is provided and 25% at launch.
- In instalments: 25% for the prototype, the rest in twelve equal monthly instalments without surcharge according to the payment plan in the offer.
- Monthly including operation (businesses only): 25% for the prototype, then 24 monthly payments that include operation. After that, section 7 applies to further operation.
6.3 Invoices are due without deduction within 14 days of receipt. Statutory default interest applies in the event of late payment. If the Client is in default with due payments, the Provider may suspend further work after giving notice in text form with a reasonable period.
6.4 Revenue sharing, where part of the price is paid from the Client’s app revenue for 24 months up to a fixed cap, is only possible under a separate agreement.
6.5 Services beyond the agreed scope are paid for at a fixed price under a separate offer or on a time basis at €90 net per hour, billed in 15-minute increments. The Provider announces any effort of more than two hours in advance.
6.6 Third-party fees paid by the Client, for example for developer accounts with Apple or Google or for domains, are not included in the price.
7. Operation
7.1 Operation covers hosting in the EU, regular backups, security and store updates and the use of AI services up to the limit set out in the offer. New features are not included.
7.2 The first three months of operation after launch are included in the package price. After that, the monthly fee stated in the offer applies.
7.3 If AI usage reaches the agreed limit, the Provider informs the Client. Additional usage requires agreement. Without agreement, AI features may be paused until the start of the following month.
7.4 The Provider ensures high availability but cannot promise uninterrupted access, in particular during maintenance, disruptions at hosting or AI providers or in cases of force majeure. Where possible, the Provider announces planned maintenance in advance.
7.5 The Client may cancel operation at any time with effect from the end of a calendar month in text form. The Provider may cancel with three months’ notice to the end of a month. Under the “monthly including operation” payment model, ordinary cancellation is excluded during the 24 months. The right to terminate for good cause remains unaffected.
7.6 When operation ends, the Client receives the source code and an export of the Client’s data in a common format, provided all due payments have been made. The Provider then deletes the data unless a statutory retention obligation applies.
8. Rights of use
8.1 Upon full payment of the package price, or with the last instalment when paying in instalments, the Client receives the exclusive, transferable right, unlimited in time and place, to use, modify, publish and distribute the app developed individually for the Client, including the source code.
8.2 General components, tools and know-how that the Provider uses across projects remain with the Provider. Where they are part of the Client’s app, the Client receives a simple, perpetual right to use them. Open-source components are subject to their respective licences.
8.3 Until full payment, the Client may use the app for testing and, during operation, within the agreed scope.
8.4 The Client’s content remains the Client’s. The Client grants the Provider the rights needed to build and operate the app.
8.5 The Provider may show the project as a reference with its name, logo and screenshots unless the Client objects in text form. Confidential content is not shown.
9. Rights in the event of defects
9.1 The statutory rights in the event of defects apply. The Provider first has the right to remedy the defect.
9.2 For businesses, claims for defects become time-barred twelve months after acceptance. This does not apply to claims for damages under section 10 or in cases of fraudulent intent. For consumers, the statutory periods apply.
9.3 Malfunctions caused by changes made by the Client or third parties, by updates to operating systems, browsers or stores released after launch, or by changed store policies are not defects. The necessary adjustments are included in operation under section 7.
10. Liability
10.1 The Provider has unlimited liability for intent and gross negligence, for injury to life, body or health, under the German Product Liability Act and where the Provider has given a guarantee.
10.2 In cases of slight negligence, the Provider is liable only for breach of an essential contractual obligation, meaning an obligation whose fulfilment makes proper performance of the contract possible in the first place and on whose fulfilment the Client may regularly rely. Liability is then limited to the foreseeable damage typical for the contract.
10.3 Within section 10.2, the Provider is liable for loss of data only up to the effort that would have been needed to restore it with regular backups.
10.4 These provisions also apply to the Provider’s agents and vicarious agents.
11. Termination before completion
11.1 Until completion, the Client may terminate the contract at any time under Section 648 BGB. The Provider may then claim the agreed remuneration but must deduct saved expenses. By law, the Provider is presumed to be entitled to 5% of the remuneration for the part not yet performed. During the decision phase after the prototype, section 3.2 takes precedence.
11.2 The right of both parties to terminate for good cause remains unaffected.
12. Right of withdrawal for consumers
Consumers have a statutory right of withdrawal for contracts concluded exclusively by means of distance communication, such as email, phone or video call, or outside business premises. So that work can begin before the withdrawal period ends, the Provider asks consumers for express confirmation when the contract is concluded.
Withdrawal policy
Right of withdrawal
You have the right to withdraw from this contract within fourteen days without giving any reason.
The withdrawal period is fourteen days from the day the contract is concluded.
To exercise your right of withdrawal, you must inform us (Edwin von Lemberg, Rollbühlstraße 89, 68309 Mannheim, Germany, phone: +49 179 2955872, email: design@edwinvonlemberg.com) of your decision to withdraw from this contract by an unequivocal statement (e.g. a letter sent by post or an email). You may use the attached model withdrawal form, but this is not obligatory.
To meet the withdrawal deadline, it is sufficient for you to send your communication concerning your exercise of the right of withdrawal before the withdrawal period has expired.
Effects of withdrawal
If you withdraw from this contract, we shall reimburse to you all payments received from you, including the costs of delivery (with the exception of the supplementary costs resulting from your choice of a type of delivery other than the least expensive type of standard delivery offered by us), without undue delay and in any event not later than fourteen days from the day on which we are informed about your decision to withdraw from this contract. We will carry out such reimbursement using the same means of payment as you used for the initial transaction, unless you have expressly agreed otherwise; in any event, you will not incur any fees as a result of such reimbursement.
If you requested to begin the performance of services during the withdrawal period, you shall pay us an amount which is in proportion to what has been provided until you have communicated us your withdrawal from this contract, in comparison with the full coverage of the contract.
End of withdrawal policy
Model withdrawal form
(Complete and return this form only if you wish to withdraw from the contract.)
- To Edwin von Lemberg, Rollbühlstraße 89, 68309 Mannheim, Germany, email: design@edwinvonlemberg.com:
- I/We (*) hereby give notice that I/We (*) withdraw from my/our (*) contract for the provision of the following service (*)
- Ordered on (*)
- Name of consumer(s)
- Address of consumer(s)
- Signature of consumer(s) (only if this form is notified on paper)
- Date
(*) Delete as appropriate.
13. Confidentiality and data protection
13.1 Both parties treat the other party’s confidential information as confidential, including after the contract ends.
13.2 How the Provider processes personal data is described in the privacy policy. If the Provider processes learners’ personal data on behalf of the Client during operation, the parties conclude a data processing agreement under Art. 28 GDPR.
14. Consumer dispute resolution
The Provider is neither willing nor obliged to take part in dispute resolution proceedings before a consumer arbitration board.
15. Final provisions
15.1 The law of the Federal Republic of Germany applies, excluding the UN Convention on Contracts for the International Sale of Goods. For consumers, this choice of law applies only insofar as it does not deprive them of the protection of mandatory provisions of the country in which they have their habitual residence.
15.2 If the Client is a merchant, a legal entity under public law or a special fund under public law, the place of jurisdiction is Mannheim.
15.3 Amendments and additions to the contract require text form. Individual agreements always take precedence.
15.4 If any provision of these Terms is invalid, the rest of the contract remains valid. The invalid provision is replaced by the statutory provision.