As of: June 2026
Note on this translation. This English text is provided for your convenience only. The legally binding version is the German original (steuertool-rechtliches.html). In the event of any discrepancy, the German version prevails. The references below are to German law, which governs this contract.
(1) These Terms and Conditions apply to the purchase of time-limited access to the web application "BTC Steuertool" (the "App") via the website alien-investor.org.
(2) The provider is the operator named in the Impressum (legal notice) (the "Provider").
(3) A consumer within the meaning of these Terms is any natural person who enters into the transaction for purposes that are predominantly outside their trade, business or profession (§ 13 of the German Civil Code, BGB).
(1) The Provider grants the customer a personal access link to the App for a period of 30 days. From CSV exports of Bitcoin brokers and wallets, the App produces calculations for private sales transactions under § 23 of the German Income Tax Act (EStG) (FiFo method), together with corresponding overviews and exports.
(2) All calculations run entirely locally in the customer's browser. The CSV files loaded by the customer are at no point transmitted to the Provider or any third party.
(3) During the access period, use is unlimited; updates to the App (e.g. additional broker formats) are included.
(4) The calculation core of the App is publicly available as open-source software (MIT license). The subject of this contract is solely the provision of the ready-to-use web application.
(1) The Provider's services do not constitute tax advice, legal advice or investment advice. The App is a technical self-help tool: it performs only automated calculations according to fixed, abstract, pre-programmed rules. No legal assessment of the individual case takes place.
(2) The reports generated by the App do not replace advice from a tax advisor. For special circumstances (e.g. mining, staking, lending, commercial trading, cross-border matters), consulting a member of the tax advisory professions is required.
(3) The Provider's support is limited to technical questions (e.g. file formats, operation of the App). Individual tax questions are not answered.
(1) The presentation of the App on the website is not a binding offer but an invitation to place an order.
(2) The customer orders by e-mail to the address stated on the website. By placing the order, the customer accepts these Terms and gives the consent to immediate performance of the contract described in the Right of Withdrawal.
(3) The contract is concluded when the Provider sends the personal access link by e-mail after receipt of payment.
(1) The price is EUR 29.00, charged once for 30 days of access.
(2) Pursuant to § 19 of the German VAT Act (UStG), no value-added tax is charged or shown (small-business rule).
(3) Payment is made, at the customer's choice, via the methods offered on the website (e.g. Bitcoin via Lightning or on-chain, or other payment services named there). For payment in Bitcoin, the conversion amount stated in the payment request at the time of payment applies.
(1) The access link is personal and non-transferable. Passing it on to third parties is not permitted.
(2) The access period begins when the link is sent and ends automatically after 30 days. No cancellation is required; no subscription arises.
(3) The Provider is entitled to block access in the event of abusive use (in particular passing on the link).
(4) 100% availability is not owed. Brief interruptions (e.g. maintenance) are possible. In the event of longer outages, the Provider will extend the access period appropriately.
(1) The quality of the calculations depends entirely on the data loaded by the customer. The customer is responsible for the accuracy and completeness of their CSV exports. The Provider does not check the customer's transaction data and, due to the local processing (§ 2 para. 2), is technically unable to do so.
(2) The customer is obliged to review the generated reports on their own responsibility before using them with third parties (in particular tax authorities). Responsibility for the content and accuracy of their tax return lies solely with the customer.
(3) The App reflects the legal status at the time of provision. Tax rules may change; no guarantee is given for continued up-to-dateness.
The statutory warranty rights for digital products apply (§§ 327 et seq. BGB). A particular tax outcome, a particular tax treatment by tax authorities, or the recognition of the generated reports by third parties is not an agreed characteristic of the App.
(1) The Provider is liable without limitation for intent and gross negligence, as well as for damages arising from injury to life, body or health.
(2) For slight negligence, the Provider is liable only for the breach of essential contractual obligations (cardinal obligations), i.e. obligations whose fulfilment makes the proper performance of the contract possible in the first place and on whose observance the customer may regularly rely. In this case, liability is limited to the foreseeable damage typical for the contract.
(3) Otherwise, liability for slight negligence is excluded.
(4) Liability under the German Product Liability Act remains unaffected.
Consumers generally have a statutory right of withdrawal. The Right of Withdrawal below applies, together with the conditions described there for the early expiry of the right of withdrawal in the case of immediate provision of digital content.
Information on the processing of personal data is contained in the Privacy Notice.
(1) The law of the Federal Republic of Germany applies, excluding the UN Convention on Contracts for the International Sale of Goods. With respect to consumers, this choice of law applies only insofar as it does not deprive them of the protection afforded by mandatory consumer-protection provisions of their country of residence.
(2) The European Commission provides a platform for online dispute resolution: https://ec.europa.eu/consumers/odr/. The Provider is neither obliged nor willing to participate in dispute-resolution proceedings before a consumer arbitration board.
(3) Should individual provisions of these Terms be invalid, the validity of the remaining provisions remains unaffected.
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 on which the contract was concluded.
To exercise your right of withdrawal, you must inform us (contact details see Impressum, e-mail: kontakt@alien-investor.org) of your decision to withdraw from this contract by means of a clear statement (e.g. by e-mail). You may use the attached model withdrawal form, but this is not mandatory.
To meet the withdrawal deadline, it is sufficient that you send your notification concerning the exercise of the right of withdrawal before the withdrawal period has expired.
If you withdraw from this contract, we shall reimburse all payments received from you without undue delay and at the latest within fourteen days from the day on which we receive notification of your withdrawal from this contract. For this reimbursement we use the same means of payment that you used for the original transaction, unless expressly agreed otherwise with you; in no case will you be charged any fees because of this reimbursement.
Note on Bitcoin payments: In the case of payment in Bitcoin, reimbursement is made in Bitcoin in the amount of the Bitcoin originally paid, unless expressly agreed otherwise.
In the case of a contract for the supply of digital content not on a tangible medium, the right of withdrawal expires if we have begun performance of the contract after you have
In concrete terms: We begin performance of the contract when we send your personal access link. You give your consent and confirmation of knowledge in your order e-mail (see the order template on the product page).
(If you want to withdraw from the contract, please complete this form and send it back.)
To: kontakt@alien-investor.org
I/we (*) hereby withdraw from the contract concluded by me/us (*) for the purchase of the following goods (*)/the provision 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 appropriate.
This notice supplements the general privacy information of alien-investor.org.
The most important thing first: your transaction data never leaves your browser. The App processes your CSV files entirely locally on your device. There is no upload, no storage and no transmission of your financial data to us or to third parties. This is not a mere promise but built that way by design — the calculation core is open source and verifiable. All technical components too (Python runtime, fonts) are loaded from our own server — no third-party CDNs.
1. Order (legal basis: Art. 6(1)(b) GDPR) — When you order by e-mail, we process your e-mail address, the content of your order and the payment information (e.g. receipt of a Bitcoin payment). We store this data to perform the contract and for the duration of statutory retention obligations (§ 147 of the German Fiscal Code (AO): 8 years for accounting records).
2. Accessing the App (legal basis: Art. 6(1)(f) GDPR) — When you access your link, our server (location: Germany, Hetzner Online GmbH) processes technically necessary connection data (IP address, time, file requested) in server logs. The server also counts the calls to your access link (with no reference to content). Log data is automatically deleted after a short time.
3. Local storage on your device — The App stores in your browser's localStorage: the colour scheme and cached exchange rates (EUR/CHF/USD). This data stays on your device and can be deleted by you at any time via your browser settings. No cookies are set for tracking purposes; there is no analytics.
4. Exchange-rate retrieval (only if needed) — If your data contains purchases in a foreign currency (CHF/USD), your browser retrieves historical exchange rates from the frankfurter.app API. In doing so, that service receives your IP address and the requested dates — but not amounts, transactions or any other content. Anyone who wants to avoid this can enter the rates manually in advance into an fx_cache.json (see the instructions in the repository).
You have the rights under Art. 15–21 GDPR (access, rectification, erasure, restriction, data portability, objection) as well as the right to lodge a complaint with a supervisory authority (Art. 77 GDPR). Controller within the meaning of the GDPR: see Impressum.