Last updated: 6 October 2026
These Terms of Use (the "Terms") form an agreement between you and Übelacker Solutions GmbH, Bläsiring 28, 4057 Basel, Switzerland ("we", "us", "our"), regarding the Letter application for iPhone, iPad, Mac and Android together with the server services it uses (together, the "App").
By installing or using the App, you agree to these Terms. If you do not agree, do not install or use the App.
You may use the App only if you are at least 16 years old and able to enter into a binding contract. If you are under 16, you may not use the App.
You may use the App for personal purposes or for the internal purposes of a business. If you use the App on behalf of a company or other organisation, you confirm that you are authorised to accept these Terms on its behalf, and the provisions of these Terms that apply specifically to consumers do not apply to you.
You may not use the App if applicable law prohibits you from doing so, or if we have previously terminated your access.
Subject to these Terms, we grant you a limited, personal, non-exclusive, non-transferable and non-sublicensable licence to install and use the App on devices you own or control, in accordance with the usage rules of the app store from which you obtained it. For the Apple App Store, this includes use on Apple-branded products that you own or control and any use permitted by the Family Sharing or volume purchasing rules.
All rights not expressly granted to you are reserved by us. This licence ends as set out in Section 15.
The App is free to use for writing, printing and exporting letters. Certain features ("PRO Features") require a paid purchase — see Section 4.
The App, including its software, source code, design, user interface, texts, graphics, the letter templates we supply, the names "Letter", "Briefe", "Cartas", "Lettre", "Lettere" and "Brieven" under which it is published, and our logos, is owned by us or our licensors and is protected by copyright, trade mark and other laws. Nothing in these Terms transfers any of those rights to you.
You may use the letter templates we supply to write your own letters, including for business purposes. You may not extract, redistribute or resell the template collection itself.
The App contains third-party and open-source components that are licensed under their own terms. Where those terms conflict with these Terms, they prevail for the component concerned. A list of these components is available on request from support@letter-app.com.
4.1 Free and paid features. Downloading the App and using it to write, lay out, print and export letters is free. The PRO Features require a paid purchase. They currently are: saved senders, letter templates of your own, per-letter settings and text formatting, capturing a handwritten signature, and the AI writing suggestions described in Section 7.
4.2 Your contract for the purchase is with the app store. The PRO Features are sold, billed and delivered through your Apple App Store or Google Play account. The purchase contract is concluded between you and the relevant store operator, not with us. The store's terms apply in addition to these Terms. We cannot process payments, refunds or cancellations ourselves.
4.3 Two ways to buy. You may unlock the PRO Features either through a subscription, which renews automatically, or through a one-time purchase, which does not renew and does not need to be cancelled.
4.4 Automatic renewal. A subscription renews automatically for the period you selected unless you cancel it at least 24 hours before the end of the current period, or within any other period the store requires, through your store's subscription settings.
4.5 What "one-time" means. The one-time purchase permanently unlocks the PRO Features offered at the time of purchase for your store account. "Permanently" means for as long as we operate the App, in accordance with Sections 9 and 15; it does not create an entitlement to the App being operated for an unlimited period. Features we add later may require a separate purchase or a subscription.
4.6 Free trials. A free trial converts automatically into a paid subscription unless you cancel before the trial ends.
4.7 Prices and price changes. The store handles payment processing and shows the price in the App and in the store before you purchase. Price changes for a subscription take effect only from the next subscription period and are announced in advance.
4.8 Refunds and cancellation rights. Refunds are governed by the refund policy of the store you purchased through, and are handled by the store. Any statutory right of withdrawal or cancellation you may have as a consumer is exercised through the store, in accordance with its terms.
4.9 What happens when a subscription ends. Your letters stay intact and accessible, and you can still write, print and export them. Senders, templates and signatures you already created remain on your device, and the settings you already applied to a letter keep working. Ending the subscription only removes the ability to use the PRO Features listed in Section 4.1.
4.10 Changes to the PRO feature set. We may change which features are included in the PRO Features. We will announce material changes in advance. If a change materially reduces the features you are paying for, you may cancel your subscription through your store.
You must not:
6.1 Your content stays yours. Everything you write — letters, senders, templates, signatures ("your content") — belongs to you. We claim no ownership of it.
6.2 Where it lives. Your content is stored on your device. On iPhone, iPad and Mac it syncs through your own private iCloud if you have that switched on; that is Apple's service to you, not ours, and the data does not pass through our servers. On Android there is no sync: your content stays on the device you wrote it on.
6.3 The permission you give us. So that we can run the features you use, you grant us a worldwide, non-exclusive, royalty-free, terminable licence to process the parts of your content that a feature actually needs, and to pass them to the service providers named in our Privacy Policy. In practice this concerns one feature only: the AI writing suggestions, which send the subject and body of the letter you are working on to our server and from there to our AI provider.
This permission is limited to what is needed to operate the features you use, and it lasts only as long as you use them. We do not use your content to train machine-learning models, and we do not use it for advertising or sell it.
6.4 Other people's data. A letter usually contains someone else's name and address. You decide what you write and whom you write to, and you are responsible for having a legal basis for it. Please do not put other people's sensitive information, identity documents or payment details into the AI writing suggestions.
6.5 Posting and delivery. The App writes, lays out and exports letters. It does not post them. Printing, enveloping, franking and delivery are yours to arrange, and we are not responsible for anything that happens to a letter after it leaves the App.
6.6 Backups are your responsibility. You must keep your own backups of anything important — for example by exporting a letter as PDF. The App is not a backup service and is not designed as one.
The App can suggest a draft, rewrite a passage or translate a letter. To do this, the subject and body of the letter, the language and the country you are writing to are transmitted to our server and from there to a third-party AI provider, as described in our Privacy Policy. The App asks for your consent before it uses this feature for the first time, and you can decline and keep using the rest of the App.
These outputs are automated suggestions and may be wrong, incomplete or inappropriate. We give no warranty as to their accuracy, completeness or suitability. Read a suggestion before you rely on it, and in particular before you print and send a letter.
You must not rely on the App's automated output for any decision with legal, financial, medical, safety-related or other significant consequences. A letter with legal effect — a notice of termination, an objection, anything with a deadline — is your responsibility, including its wording, its accuracy and its timing.
We apply a daily limit to the number of AI requests per installation, to keep the feature available for everyone.
If you send us ideas, suggestions, feature requests or other feedback, you grant us a perpetual, irrevocable, worldwide, royalty-free right to use, modify and implement it without restriction and without any obligation to compensate or credit you. Please do not send us anything you consider confidential.
We may modify, suspend or discontinue the App or any of its features at any time.
The AI writing suggestions depend on our servers and our AI provider being reachable and may be temporarily or permanently unavailable. Everything else — writing, laying out, printing and exporting letters — is designed to keep working offline.
We may apply reasonable technical limits, for example on request rates and text lengths, to keep the service available for everyone.
We may amend these Terms where there is a valid reason to do so — for example changes in the law or in case law, new or changed features, security requirements, or changes in the service providers we rely on.
We will notify you of material changes in the App or at letter-app.com at least 30 days before they take effect, unless a change has to take effect sooner for legal or security reasons.
If you do not agree to a change, you may stop using the App and cancel any subscription through your store before the change takes effect. If you continue to use the App after that date, the amended Terms apply. Your mandatory statutory rights are not affected.
The App relies on services provided by third parties, including Apple (App Store, iCloud, App Attest), Google (Google Play, Play Integrity), our hosting provider, our AI provider, RevenueCat and your mobile network operator. Their own terms apply to your use of those services, and we are not responsible for their availability, performance or acts.
When using the App you must comply with any applicable third-party terms of agreement — for example the terms of your wireless data service plan.
To the maximum extent permitted by applicable law, the App is provided "as is" and "as available", and we exclude all warranties, whether express or implied, including any implied warranty of merchantability, fitness for a particular purpose and non-infringement. We do not warrant that the App will operate uninterrupted or error-free, that a letter will print exactly as it appears on screen on every printer, or that data will not be lost or corrupted.
This Section applies only to the extent the law permits. In particular, if you are a consumer, your mandatory statutory rights under the law of your country of residence — including rights concerning the conformity of digital content and digital services — remain unaffected, and in respect of a paid purchase of the PRO Features we remain liable for conformity to the extent mandatory law requires.
13.1 Unlimited liability. We are liable without limitation for damage caused intentionally or by gross negligence, for death, bodily injury or damage to health, for fraudulently concealed defects, and in any other case where mandatory law does not permit a limitation of liability.
13.2 Slight negligence. In cases of slight negligence, we are liable only for breach of an obligation that is essential to the purpose of this agreement, and our liability is limited to the damage that is typical for a contract of this kind and was foreseeable when it was concluded.
13.3 Overall cap. Subject to Section 13.1, our total aggregate liability for all claims arising in any twelve-month period is limited to the total amount you paid for the PRO Features in the twelve months before the event giving rise to the liability. If you have not paid for the PRO Features, that amount is nil.
13.4 Excluded losses. Subject to Section 13.1, we are not liable for indirect, incidental, special or consequential damage, nor for loss of profit, loss or corruption of letters or other data, loss of goodwill, or business interruption. In particular, we are not liable for the consequences of a letter being sent late, not at all, with the wrong content or to the wrong recipient.
13.5 Third parties and auxiliary persons. To the extent permitted by law, we are not liable for the conduct of auxiliary persons (Art. 101 of the Swiss Code of Obligations), nor for the availability, performance or acts of the third-party services described in Section 11.
13.6 Our people. The limitations in this Section apply equally to our directors, employees, contractors and agents.
To the extent permitted by applicable law, you will indemnify us and hold us harmless against third-party claims, damage and reasonable legal costs arising from (a) your content, (b) the letters you write and send, (c) your breach of these Terms, or (d) your infringement of third-party rights.
This does not apply where you are a consumer and the claim does not arise from a culpable breach of these Terms on your part. We will notify you of any such claim without undue delay and will not settle it without consulting you.
This licence runs until it is terminated.
You may terminate it at any time by deleting the App from your devices and cancelling any subscription through your store.
We may suspend or terminate your access with immediate effect if you materially breach these Terms, if we are required to do so by law or a competent authority, or if it is necessary to protect the security or integrity of the service or other users. Where it is reasonable and lawful to do so, we will warn you first and give you an opportunity to put matters right.
We may also terminate this agreement for convenience on 30 days' notice. If you have a paid subscription running at that time, you may cancel it through your store, and we will support a request to the store to refund the unused portion.
On termination you must stop using the App and delete it from your devices. Deleting data held on your own device or in your own iCloud account is your responsibility.
Survival. Sections 3, 5, 6.3 to 6.6, 7, 8, 12, 13, 14, 16 to 19 and 21 survive termination.
We are not liable for any delay or failure in performance caused by events outside our reasonable control, including outages at our hosting or AI providers, network and telecommunications failures, cyberattacks, acts of government or regulators, industrial action and natural events.
You represent and warrant that you are not located in, and are not a national or resident of, a country subject to a Swiss, EU, UK or U.S. embargo or designated by the U.S. Government as a "terrorist supporting" country, and that you are not listed on any Swiss, EU, UK or U.S. list of restricted, prohibited or sanctioned parties.
You must not use or export the App in breach of applicable export control or sanctions laws.
These Terms are governed by Swiss law, excluding its conflict-of-law provisions and the United Nations Convention on Contracts for the International Sale of Goods.
The exclusive place of jurisdiction is Basel, Switzerland.
If you are a consumer, this choice of law does not deprive you of the protection afforded to you by mandatory provisions of the law of your country of residence, and you may also bring proceedings before the courts of your place of domicile.
19.1 Severability. If any provision of these Terms is or becomes invalid or unenforceable, the remaining provisions remain in force. The invalid provision is replaced by a valid provision that comes as close as possible to its commercial purpose.
19.2 No waiver. If we do not enforce a provision of these Terms, that is not a waiver of our right to enforce it later.
19.3 Assignment. You may not assign or transfer your rights under these Terms. We may assign these Terms to a group company, or in connection with a merger, acquisition or sale of assets, provided your rights under these Terms are not reduced.
19.4 Entire agreement. These Terms, together with our Privacy Policy and the terms of the app store you obtained the App from, constitute the entire agreement between you and us regarding the App.
19.5 Language. These Terms are published in English, German, French, Spanish, Italian, Dutch and Portuguese. If you are a consumer, the version in the language in which these Terms were presented to you applies. In all other cases, the German version prevails in the event of discrepancies.
19.6 Notices. We may give you notice in the App, at letter-app.com, or — where we hold your address — by email. Notices to us go to support@letter-app.com or to the postal address above.
19.7 Consumer dispute resolution. We are neither obliged nor willing to participate in dispute resolution proceedings before a consumer arbitration board.
If you obtained the App from the Apple App Store, the following also applies:
If you obtained the App from Google Play, the Google Play Terms of Service apply in addition to these Terms. Google is not a party to these Terms and is not responsible for the App.
Questions about these Terms: support@letter-app.com
Übelacker Solutions GmbH
Bläsiring 28
4057 Basel
Switzerland
