Terms of Use

Who you are dealing with

KeyFu is operated by Martin Neuschulz, Kurt-Eisner-Straße 58, 04275 Leipzig, Germany, a sole proprietor. Contact: hi@keyfu.app. Full details are in the legal notice. These terms apply to the KeyFu app and the services behind it. Apple’s App Store terms apply as well.

What KeyFu is

KeyFu is a practice tool for iPhone and iPad that works with a MIDI keyboard. It reads what you play, builds exercises around goals you set, and gives feedback while you play.

KeyFu judges your playing from MIDI alone, which means the notes, their timing and how hard you struck them. It does not see your hands, so it cannot judge hand position, posture or fingering. It is not a substitute for a teacher, and nothing in it is a promise about how quickly you will learn anything.

Your practice history is stored only on the device you practice on. We keep no copy on our server and cannot restore it. Your device’s own backup keeps it (on iPhone and iPad, iCloud Backup or a computer backup; on a Mac, a backup of the Mac); deleting the app without such a backup deletes it, and signing in on another device does not bring it over. You can export it at any time with Export My Data in Settings.

Beta

KeyFu is currently in beta, distributed through Apple’s TestFlight. That means it is unfinished on purpose. Features change, things occasionally break, and some of what you see will be replaced. We can end the beta, or your access to it, at any time, for example when a test round closes. What you practiced stays on your device. Joining the waitlist is not a guarantee of an invitation. During the beta you pay nothing. Purchases in a TestFlight build are free and do not carry over to the App Store version.

Your account

You need an account to use the app, created through Sign in with Apple. During the beta you must be at least 18 years old. You are responsible for the Apple Account it rests on. When you create your account, you agree to these terms. This creates an agreement between you and us, including for the free parts of KeyFu, for an indefinite period. You can end it at any time by deleting your account from inside the app, which also deletes the data our server stores under your account (the privacy policy explains what it does not reach). Deleting your account does not cancel a KeyFu Pro subscription. Cancel it in your App Store settings.

Withdrawing from the agreement

If you are a consumer, you can withdraw from your agreement with us within 14 days without giving a reason. The period starts on the day you create your account.

To withdraw, tell us clearly that you are withdrawing, by email to hi@keyfu.app or by post to the address above. You can use the model form below, but you don’t have to. Sending your notice before the 14 days are over is enough.

If you withdraw, the agreement ends and we delete your account. The free version costs nothing, so there is nothing to pay back. Purchases of KeyFu Pro are withdrawn through Apple (see “Paying for it”).

Model withdrawal form (complete and return this form only if you wish to withdraw from the contract)

• To Martin Neuschulz (KeyFu), Kurt-Eisner-Straße 58, 04275 Leipzig, Germany, hi@keyfu.app:
• I hereby give notice that I withdraw from my contract for the provision of the following service: the KeyFu service.
• Ordered on (the day you created your account):
• Name of consumer:
• Address of consumer:
• Signature of consumer (only if this form is notified on paper):
• Date:

Using the coach fairly

The coach is a conversational feature that costs real money to run per message. That is why it comes with a message allowance, which the app shows you, and the free version has a smaller one. You agree not to use the coach for anything other than practicing music with KeyFu. In particular, you agree not to automate requests, resell access, use it as a general-purpose assistant, or enter unlawful or abusive content. We may limit or withdraw access where use is clearly outside that purpose. For a serious breach this can happen without warning.

Coach replies are generated by AI, and they can be wrong. They are not medical or health advice. Use your judgment, and stop if something hurts. The coach is not for emergencies. If you are in danger, contact your local emergency services.

Your content

What you play and the goals you write stay yours. We process them only to run the service, as described in the privacy policy. We do not claim ownership of your music. The app itself, its exercises and its training logic remain ours. You get a personal, non-transferable right to use them while your account exists.

Paying for it

Some features are part of KeyFu Pro, a subscription that renews monthly or yearly. It is sold through the App Store. Depending on your country, Apple sells it in its own name or as our agent. Price, term and renewal are shown in Apple’s purchase dialog before you buy. The purchase itself is handled by Apple: billing, cancellation, refunds and withdrawal from the purchase run through your Apple Account under Apple’s terms. The subscription renews automatically unless you cancel it in your App Store settings before the renewal date. Nothing starts costing money without you confirming a purchase with Apple.

The KeyFu service itself is provided by us, under these terms. Your statutory rights towards us, including the rules for digital products, stay in place, and nothing in these terms limits them.

Availability

We aim for KeyFu to be available, but we cannot promise uninterrupted service. Maintenance, faults, or outages at providers we rely on (in particular the AI providers) can interrupt the features that need the internet. Practicing works without a connection wherever it can. This does not limit your statutory rights if a feature you are entitled to does not work.

Warranty

The statutory rules apply. For consumers, this includes the rules for digital products (§§ 327 ff. of the German Civil Code, BGB) and the duty to provide updates.

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. For slight negligence we are liable only where a material contractual obligation is breached, meaning one whose fulfilment makes the agreement possible in the first place and on which you may regularly rely. In that case liability is limited to damage that was foreseeable and typical for this kind of agreement. Otherwise we are not liable for slight negligence.

Changes to the service

KeyFu will keep changing. We may change the service where there is a valid reason, such as new technology, security, a legal requirement, or a feature that too few people use to keep it running. This includes what the free version contains and how large its allowances are. Two things stay free in any case: setting and changing your own goals, and the exercise library with its ready-made routines. A change never adds a charge to your agreement: you only pay if you choose to buy KeyFu Pro. We tell you about a change in the app beforehand. What you have already paid for keeps working until the end of the period you paid for.

If a change makes the service more than slightly worse for you, you can end the agreement free of charge within 30 days of being told, or of the change, whichever is later. To end it, delete your account, and if you pay for KeyFu Pro, cancel it in your App Store settings.

Changes to these terms

A new version of these terms applies to you only once you agree to it. We will ask in the app. If you do not agree, the version you agreed to continues to apply, and you can end the agreement at any time by deleting your account. The date at the top tells you which version you are reading.

How the agreement is made

You make the agreement in the app, by tapping Sign in with Apple on the screen that links these terms. On the Canadian App Store the terms are shown in full first: you tap “J’accepte”, or “I agree” after choosing the English version, and then confirm in Apple’s sign-in sheet. Until then you can leave at any time and nothing is agreed, and Apple’s sign-in sheet lets you cancel before you confirm. We keep a record of which version and language of these terms you agreed to, and when. The current version is always at keyfu.app/terms, and we send you the version you agreed to on request. The agreement is concluded in English. On the Canadian App Store it is concluded in French, unless you expressly chose the English version before signing in.

Applicable law and disputes

German law applies, excluding the UN Convention on Contracts for the International Sale of Goods. If you are a consumer, this does not remove the protection of the mandatory law of the place where you live.

We are not obliged and not willing to take part in dispute resolution proceedings before a consumer conciliation body (§ 36 of the German Consumer Dispute Resolution Act, VSBG).

If a clause in these terms is invalid, the rest remain in force.