Terms of Service (AGB)

Effective date: 5 July 2026

Section 1 Scope and Provider

(1) These Terms of Service (the "Terms") govern the use of the web-based application "Butterbill", accessible at https://butterbill.app (the "Service" or "Butterbill"), between the provider and the user.

(2) The provider and contracting party is:

Johann Philipp Strathausen
Sole proprietor (freelance)
Krachtstr. 8
10245 Berlin
Germany

Email: philipp@stratha.us
VAT ID: DE294406882

(the "Provider", "we" or "us").

(3) Users within the meaning of these Terms are both consumers (Section 13 German Civil Code, BGB) and businesses/entrepreneurs (Section 14 BGB) who use the Service. A consumer is any natural person who enters into a legal transaction for purposes that predominantly are outside their trade, business or profession. A business/entrepreneur is a natural or legal person or a partnership with legal capacity that, when entering into a legal transaction, acts in the exercise of its trade, business or profession.

(4) These Terms apply exclusively. Any deviating, conflicting or supplementary general terms and conditions of the user shall only become part of the contract if and to the extent that we have expressly agreed to their application in writing.

(5) The version of these Terms in force at the time the contract is concluded shall apply.

Section 2 Description of the Service

(1) Butterbill is a chat-based application for creating and managing invoices. The user creates and manages invoices in dialogue with an AI-assisted assistant. The application performs the amount-related calculations deterministically (rule-based) and generates invoice documents as PDFs as well as electronic invoices in the ZUGFeRD and XRechnung formats.

(2) The substantive content (e.g. descriptions of services, amounts, tax rates, names and addresses of clients, VAT identification numbers) is provided by the user or determined in dialogue with the assistant.

(3) User's own responsibility. The user remains solely responsible for the legal and tax correctness, completeness and admissibility of the invoices they create and of the underlying information. This includes in particular the correct application of tax rates, compliance with the statutory mandatory particulars on invoices (e.g. Section 14 German VAT Act, UStG), the correct treatment of the small-business scheme, reverse charge and intra-Community supplies, as well as compliance with commercial and tax retention obligations.

(4) No tax or legal advice. Butterbill is a software tool and does not constitute tax, legal or any other advice. Outputs, notes or suggestions of the AI assistant do not replace individual professional advice from a tax advisor or lawyer. The user is required to check the documents generated by the Service before using them.

(5) Note on AI-generated content. The AI assistant may produce erroneous, incomplete or inappropriate outputs. No automated decision-making producing legal effects within the meaning of Art. 22 GDPR takes place.

(6) Further development of the Service. We are entitled to further develop and adjust the scope of the Service and to change individual features, provided this is reasonable for the user and the contractually owed core of the service is not materially impaired. Where the Service is a digital product supplied to a consumer for payment, changes that go beyond what is necessary to maintain conformity are additionally and primarily governed by the requirements of Section 6 of these Terms (Section 327r BGB).

Section 3 Registration and User Account

(1) Use of the Service requires the creation of a user account. A valid email address and a display name are required for registration.

(2) Magic-link sign-in. Sign-in is carried out via a single-use sign-in link (magic link) sent to the email address provided by the user. The user must ensure that only they have access to the associated email inbox. We recommend securing access to the email inbox appropriately.

(3) The user is obliged to provide truthful and complete information upon registration and to keep such information up to date in the event of changes.

(4) The user must protect their access credentials and access to their email inbox from unauthorised third-party access. If misuse of the account is suspected, this must be reported without undue delay.

(5) There is no entitlement to the creation of an account or to the conclusion of a contract. We are entitled to refuse registration without giving reasons.

Section 4 Conclusion of Contract and Information on Electronic Commerce

(1) The Service may be offered as a free basic use and/or as a paid variant ("Butterbill Pro").

(2) Free contract. Upon registration and creation of the account, a contract for the free use of the respectively offered free features is concluded at no charge. The personal data provided by the user in the course of the free use (email address, display name and the content entered) is processed by us solely to provide the Service and to comply with legal obligations, and not for any other purpose; no use for advertising, analytics or tracking takes place. Because the data provided by the user is thus processed exclusively for the purposes set out in Section 312(1a) sentence 2 BGB, the consumer-protection provisions on off-premises contracts and distance contracts, including the right of withdrawal, do not apply to the free contract. The user may terminate the free contract at any time by deleting the account in accordance with Section 8.

(3) Paid contract – order ("button solution"). A paid contract for "Butterbill Pro" is concluded when the user selects the paid plan during the ordering process and places the order by clicking the button labelled "order with obligation to pay" ("zahlungspflichtig bestellen") or with a correspondingly unambiguous wording. Immediately before the user places the order, the essential characteristics of the service, the total price including any taxes, as well as the term of the contract and the conditions for termination are displayed to the user in a clear and comprehensible manner and in a highlighted form (Section 312j(2) BGB in conjunction with Art. 246a EGBGB). We confirm the conclusion of the contract without undue delay in text form (e.g. by email).

(4) Technical steps and correction of input errors. The ordering process comprises the selection of the plan, the entry or confirmation of the required information, the display of an order summary and the placing of the order via the button pursuant to paragraph 3. Before placing the order, the user can view and change their entries at any time using the customary keyboard and mouse functions and the correction and "back" functions provided during the ordering process (Section 312i(1) sentence 1 no. 1 BGB in conjunction with Art. 246c EGBGB).

(5) Storage of the contract text. We store the contract text (the specific order data and the version of these Terms in force at the time the contract is concluded) and send the user this information together with the order confirmation in text form. The current version of these Terms is also available at any time at https://butterbill.app, where it can be saved and printed.

(6) Contract language. The contract can be concluded in German. This English version is provided for ease of understanding only; in the event of any discrepancy between the language versions, the German version shall prevail.

Section 5 Prices and Payment

(1) The paid variant "Butterbill Pro" can be booked for the following billing periods:

Monthly: EUR 10 per month;
Annually: EUR 96 per year (equivalent to EUR 8 per month, approx. 20% saving).

(2) Price statements. Vis-à-vis consumers, the above prices are total prices and are inclusive of statutory value added tax (final prices; e.g. EUR 10 per month incl. VAT). Vis-à-vis businesses/entrepreneurs, the above amounts are net prices plus the applicable statutory value added tax.

(3) Billing period and due date. The selected subscription is payable in advance at the beginning of each billing period (monthly or annually). The term of the contract and its renewal are governed by Section 8.

(4) Payment. Payment is made via the payment methods offered during the ordering process. The invoice amount is due upon conclusion of the contract or at the beginning of the respective billing period.

(5) If the user is in default of payment, we are entitled, after prior notice, to block access to the paid features. Statutory claims, in particular claims for default interest, remain unaffected.

(6) Price changes.

a) Vis-à-vis consumers, an increase in the price for an ongoing subscription constitutes an offer to amend the contract. We will notify the consumer of an intended price change in text form at least six weeks before the intended effective date. The change only takes effect if the consumer expressly agrees to it (e.g. by active confirmation within the Service). If the consumer does not agree to the change by the intended effective date, the contract continues at the previous price; in this case we are entitled to terminate the contract by ordinary notice with effect from the end of the current billing period. A billing period that is already running and has been paid in advance is not affected by a price change.

b) Vis-à-vis businesses/entrepreneurs, we will notify price changes in text form at least six weeks before they take effect. If the entrepreneur does not object to the change before it takes effect, the change shall be deemed accepted; we will point this out separately in the notice. If the entrepreneur objects, either party is entitled to terminate the contract as of the date on which the change takes effect.

Section 6 Consumer Rights for Digital Products (Sections 327 et seq. BGB)

(1) Where we supply a consumer with a digital product (digital content or digital services) within the meaning of Sections 327 et seq. BGB against payment of a price, the following provisions apply. The consumer's statutory rights under Sections 327 et seq. BGB are not excluded, limited or circumvented by these Terms (Section 327s BGB); to that extent, any conflicting provisions of these Terms do not apply vis-à-vis consumers.

(2) Conformity. We owe the consumer the supply of a digital product that conforms with the contract and are liable for its subjective and objective conformity in accordance with Sections 327d et seq. BGB (Section 327e BGB).

(3) Updates (Section 327f BGB). During the relevant period we will provide the consumer with the updates, including security updates, that are necessary to maintain the conformity of the digital product, and we will inform the consumer about them. In the case of continuous supply (subscription), this obligation extends over the entire supply period; otherwise, it extends over the period the consumer can reasonably expect given the type and purpose of the digital product.

(4) Changes going beyond conformity (Section 327r BGB). We will make changes to the digital product that go beyond what is necessary to maintain conformity only under the following conditions:

a) there is a valid reason, in particular adapting the product to a new technical environment or to an increased number of users, a change in the legal situation or supreme-court case law, necessary security measures, or the further development of the Service in general;

b) the change entails no additional cost for the consumer;

c) we inform the consumer clearly and comprehensibly about the change; and

d) if the change adversely affects the accessibility or usability of the digital product to more than a merely insignificant extent, we additionally inform the consumer, within a reasonable period before the time of the change and on a durable medium, of the features and time of the change and of the consumer's right to terminate the contract and – where applicable – of the option to continue using the digital product unchanged.

(5) If a change under paragraph 4 adversely affects the access to or usability of the digital product to more than a merely insignificant extent, the consumer may terminate the contract free of charge within 30 days of receipt of the information or of the time of the change, whichever is later. This does not apply if the adverse effect is only insignificant or if we enable the consumer to continue using the digital product unchanged at no additional cost.

Section 7 Right of Withdrawal for Consumers

For paid contracts, consumers have a statutory right of withdrawal in accordance with the following withdrawal instructions. No right of withdrawal exists for contracts that are not consumer contracts within the meaning of Sections 355 et seq. BGB (in particular vis-à-vis businesses/entrepreneurs). Regarding the free contract, see Section 4(2).

Withdrawal Instructions

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 of the conclusion of the contract.

To exercise your right of withdrawal, you must inform us

Johann Philipp Strathausen
Krachtstr. 8
10245 Berlin
Germany
Email: philipp@stratha.us

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 mandatory.

To meet the withdrawal deadline, it is sufficient for you to send your communication concerning the 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 without undue delay and no later than fourteen days from the day on which we receive notification of your withdrawal from this contract. For this reimbursement, we will use the same means of payment that you used for the original transaction, unless expressly agreed otherwise with you; in no event will you be charged any fees as a result of this reimbursement.

If you requested that the provision of services should begin during the withdrawal period, you shall pay us a reasonable amount corresponding to the proportion of the services already provided up to the point in time at which you inform us of the exercise of the right of withdrawal with regard to this contract, compared with the total scope of the services provided for in the contract. Such compensation for value is only owed if you expressly requested that we begin performance before the end of the withdrawal period and if, before you submitted your contractual declaration, we informed you of this payment obligation in accordance with Section 357(8) BGB.

Early expiry of the right of withdrawal

In the case of a contract for the provision of services, the right of withdrawal expires if we have fully provided the service and only began performing the service after you gave your express consent and at the same time confirmed your acknowledgement that you would lose your right of withdrawal upon complete performance of the contract by us (Section 356(4) BGB). In the case of digital content not supplied on a tangible medium, the right of withdrawal expires if we have begun performance of the contract after you have expressly consented to us beginning performance before the end of the withdrawal period, you have confirmed your acknowledgement that by giving your consent you lose your right of withdrawal upon the beginning of performance, and we have provided you with confirmation of this (Section 356(5) BGB).

Note: We obtain this express consent and the confirmation of your acknowledgement of the loss of the right of withdrawal separately during the ordering process (e.g. via a dedicated selection field). If you do not give this consent, your right of withdrawal remains in place for the duration of the fourteen-day period.

Model Withdrawal Form

(If you want to withdraw from the contract, please fill in this form and send it back.)

To:
Johann Philipp Strathausen
Krachtstr. 8
10245 Berlin
Germany
Email: philipp@stratha.us

I/we () hereby withdraw from the contract concluded by me/us () for the purchase of the following service (*):

Ordered on () / received on (): __________________

Name of consumer(s): __________________

Address of consumer(s): __________________

Signature of consumer(s) (only for notification on paper): __________________

Date: __________________

(*) Delete as applicable.

Section 8 Term and Termination

(1) Free contract. The free use contract is concluded for an indefinite period. The user may terminate it at any time by deleting their account. We may terminate the free contract with a notice period of fourteen days in text form.

(2) Paid subscription. The "Butterbill Pro" subscription initially has the initial term selected by the user (monthly or annually).

a) Consumers: After the initial term expires, the subscription is extended for an indefinite period. The consumer may terminate the subscription extended for an indefinite period at any time with a notice period of no more than one month. The consumer may terminate the initial term with effect from the end of that term.

b) Businesses/entrepreneurs: If the entrepreneur does not terminate the subscription with effect from the end of the respective term, it is renewed for a further period equal in length to the term originally selected; it may be terminated with effect from the end of the current period.

(3) Form of termination and cancellation button. Termination may be declared in text form (e.g. by email). For consumer contracts directed at a continuing obligation and concluded online via the Service, we additionally provide an easily accessible, directly and permanently available cancellation button ("Cancel contracts here" / "Verträge hier kündigen") (Section 312k BGB). Via this button, the user reaches a confirmation page on which they can provide the information required for the termination and submit the termination by means of a confirmation button. We confirm to the user the receipt of the termination and the point in time at which the termination ends the contractual relationship without undue delay in text form (e.g. by email).

(4) The right to extraordinary termination for good cause remains unaffected for both parties. Good cause exists for us in particular if the user seriously or repeatedly breaches these Terms.

(5) Upon termination of the contractual relationship, we are entitled to delete the account and the associated data in accordance with the statutory provisions and our privacy policy. The user is responsible for backing up their data in good time (see Section 12).

Section 9 Availability, Maintenance, Updates

(1) We endeavour to keep the Service available as far as possible. Vis-à-vis users who do not obtain the Service as a digital product for payment (in particular under the free basic use), we do not owe any particular level of availability and do not provide any availability guarantee (best-effort provision). Vis-à-vis consumers to whom we supply "Butterbill Pro" as a digital product for payment, the statutory provisions on conformity and supply apply (Sections 327 et seq. BGB, Section 6 of these Terms); the above disclaimer does not apply in that respect.

(2) Availability may be restricted by maintenance work, further development, necessary security measures and by circumstances beyond our control (e.g. disruptions at service providers used, force majeure). Where possible, we carry out plannable maintenance work during off-peak periods.

(3) The Service uses services provided by third parties (including hosting, AI processing, email delivery, object storage). Outages or changes at these service providers may affect the availability of the Service.

(4) The provision of updates to consumers is governed by Section 6(3) (Section 327f BGB).

Section 10 User Obligations and Acceptable Use

(1) The user undertakes to use the Service only within the framework of applicable law and these Terms.

(2) The user is solely responsible for all content entered via their account. The user warrants that they are entitled to process the data they enter (in particular personal data of their own clients) and that the content entered does not infringe the rights of third parties and does not violate applicable law.

(3) The user is in particular prohibited from:
a) using the Service for unlawful or fraudulent purposes, in particular to create factually false or misleading invoices;
b) introducing malware or circumventing security measures;
c) using the Service in a manner that excessively impairs its functionality, integrity or availability (e.g. automated mass queries without consent);
d) uploading or distributing unlawful, offensive, violence-glorifying, discriminatory or otherwise objectionable content;
e) making the Service available to third parties without authorisation or passing it on in breach of these Terms.

(4) In the event of a breach of these obligations, we are entitled to remove the affected content and/or to temporarily or permanently block the user's access, taking due account of the user's legitimate interests.

(5) The user shall indemnify us against justified claims asserted by third parties as a result of unlawful use of the Service for which the user is responsible or a breach of these Terms, including reasonable costs of legal defence. Vis-à-vis consumers, this applies only to the extent that the consumer is responsible for the breach of duty.

Section 11 Liability

(1) We are liable without limitation for damages arising from injury to life, body or health that are based on an intentional or negligent breach of duty by us or our legal representatives or vicarious agents, as well as for damages caused by intent and gross negligence.

(2) In the event of the slightly negligent breach of a material contractual obligation (cardinal obligation) — an obligation whose fulfilment makes the proper performance of the contract possible in the first place and on whose compliance the user may regularly rely — our liability is limited to the foreseeable damage typical for this type of contract.

(3) Otherwise, liability for slightly negligent breaches of duty is excluded.

(4) Liability under the German Product Liability Act (Produkthaftungsgesetz), under a guarantee assumed by us, and the consumer's statutory rights in respect of defects in digital products (Sections 327 et seq. BGB) remain unaffected.

(5) Insofar as our liability is excluded or limited under the preceding paragraphs, this also applies to the personal liability of our legal representatives, employees and vicarious agents.

(6) We are not liable for the substantive and legal correctness of the invoices created by the user and of the content entered by them or generated by the AI assistant in response to their input (Section 2). In this respect, the user remains solely responsible.

(7) We are liable for the loss of data only to the extent that such loss would also have occurred had the user carried out proper and regular data backups (see Section 12). This does not apply where we are guilty of intent or gross negligence.

Section 12 Data, Data Backup and Processing on Behalf

(1) The user is responsible for the data they enter and store within the Service.

(2) We recommend that the user regularly download their invoices and other important documents and back them up outside the Service, in particular with regard to statutory retention obligations (e.g. Section 147 AO, Section 257 HGB). Such external backup is the sole responsibility of the user.

(3) Data protection. Details of the processing of personal data, of the processors used, of any transfers to third countries and the associated safeguards, of the legal bases, storage periods and your data-subject rights can be found in our separate privacy policy, available at https://butterbill.app/privacy. These Terms do not replace the privacy policy.

(4) Processing on behalf. Insofar as the user processes personal data of their own clients or other third parties within the Service and is the controller in this respect under data protection law, we process such data on the user's behalf as a processor within the meaning of Art. 28 GDPR. For all users acting as controllers in this respect (in particular businesses/entrepreneurs), the data processing agreement (AVV/DPA) available at https://butterbill.app/dpa forms an integral part of these Terms; it is concluded upon use of the Service for this purpose and is therefore not dependent on a separate request. We will provide a signed counterpart on request.

Section 13 Rights of Use

(1) For the duration of the contract, the user receives a non-exclusive, non-transferable and non-sublicensable right to use the Service to the contractually agreed extent.

(2) All rights in the software, the trademarks and the other components of the Service remain with the Provider or the respective rights holders.

(3) The user retains all rights in the content they enter. The user grants us the non-exclusive right to process this content to the extent necessary to provide the Service (including processing by the processors named in the privacy policy).

Section 14 Amendments to these Terms

(1) We are entitled to amend these Terms with effect for the future insofar as this is necessary for valid reasons, such as a change in the legal situation, supreme court case law, technical requirements or in order to adapt to a changed market situation, and provided the user is not unreasonably disadvantaged as a result. The deemed-consent procedure set out below applies only to amendments of subordinate, non-essential ancillary provisions. The main performance obligations, the scope of the services owed and the price-performance ratio (fees) are excluded from this and cannot be amended in this way; price changes are governed exclusively by Section 5(6).

(2) We will notify the user of amendments within the meaning of paragraph 1 at least six weeks before they take effect in text form (e.g. by email). If the user does not object within six weeks of receipt of the notice and continues to use the Service after the amendments take effect, the amended Terms shall be deemed accepted. We will point out separately and prominently in the notice the significance of remaining silent, the start of the period and the possibility of objecting.

(3) If the user objects in good time, the contract will be continued on the previous terms. The mutual right to ordinary termination under Section 8 remains unaffected; an objection by the user to an amendment does not, in itself, entitle us to terminate.

Section 15 Final Provisions

(1) The law of the Federal Republic of Germany applies, to the exclusion of the UN Convention on Contracts for the International Sale of Goods (CISG). If the user is a consumer, this choice of law applies only insofar as it does not deprive them of the protection afforded by mandatory provisions of the law of the state of their habitual residence.

(2) If the user is a merchant, a legal person under public law or a special fund under public law, the exclusive place of jurisdiction for all disputes arising from this contractual relationship is Berlin. Mandatory statutory provisions on exclusive places of jurisdiction remain unaffected.

(3) Consumer dispute resolution. The Provider is neither obliged nor willing to participate in a dispute resolution procedure before a consumer arbitration board (Sections 36, 37 VSBG).

(4) Severability clause. Should individual provisions of these Terms be or become wholly or partially invalid or unenforceable, the validity of the remaining provisions shall not be affected. The invalid or unenforceable provision shall be replaced by the statutory rule.

(5) Amendments and supplements to this contract must be made in text form. This also applies to any amendment of this text-form clause.

Effective date: 5 July 2026