Undertow — Terms of Use

Effective 5 September 2026. Version 1.0.

These terms are an agreement between you and Flapp Bilişim Anonim Şirketi ("we", "us") covering the Undertow iOS app and the service behind it. By subscribing or using the app you accept them. If you do not, do not use Undertow.

We use our own terms rather than Apple's standard EULA because Undertow reads your mailbox, and that deserves saying out loud in the agreement rather than in a footnote. Where these terms are silent, Apple's Licensed Application End User License Agreement applies as the default.

1. What Undertow does

Undertow connects to a mailbox you own, reads the newsletters in it, and builds you a short deck of cards most nights. It is a reading tool for content you already subscribe to. It does not publish, sell, or license any content of its own.

2. Your account and your mailbox

• You must be at least 13 years old, and old enough in your country to enter into this agreement.
• You must own, or be authorised to use, the mailbox you connect. Do not connect an employer's mailbox without permission, and do not connect someone else's mailbox at all.
• You are responsible for the credential you give us and for keeping your device secure. Revoke the app password in your Google Account whenever you want; access stops immediately.
• Keep one account per person. Sharing an account defeats the taste profile anyway.

3. Subscription, price, renewal, and cancellation

Undertow is a paid subscription sold through the App Store. Apple requires these facts to be stated plainly, and they are also just the facts:

• What you get: full access to Undertow — the nightly deck, the taste loop, push delivery, and your archive.
• Length of subscription and price: - Monthly — US$12.99 per month, renewing every month. - Annual — US$99.00 per year, renewing every year. Prices in other storefronts are set from Apple's pricing tiers and are shown in your local currency, including tax where applicable, before you buy.
• Free trial: 14 days, once per Apple Account, on either plan. If you have used a trial or an introductory offer in this subscription group before, you are not eligible again, and the app will show the price without one.
• Payment is charged to your Apple Account at confirmation of purchase, or at the end of the free trial.
• Auto-renewal: the subscription renews automatically unless auto-renew is turned off at least 24 hours before the end of the current period. Your Apple Account is charged for the renewal within 24 hours before the current period ends.
• Cancelling: you cancel through Apple, not through us — Settings → your name → Subscriptions → Undertow → Cancel Subscription, or the "Manage subscription" link in Undertow's own Settings screen, which opens the same sheet. Cancelling stops the next renewal; you keep access until the end of the period you have already paid for.
• Unused trial time is forfeited if you buy a subscription while a free trial is running.
• Price changes: if we raise the price of a plan you are on, Apple asks you to agree before the next renewal, and the subscription does not renew at the higher price unless you do.
• Refunds are handled by Apple, not by us — reportaproblem.apple.com. We cannot issue a refund for an App Store purchase, though tell us what went wrong anyway and we will help you make the case.

Deleting your Undertow account does not cancel your App Store subscription. Cancel it in Settings as above, or you will keep being billed for a service you have deleted.

4. What we do with your data

The Privacy Policy is part of this agreement. The essentials: the mailbox connection is read-only; only messages that carry a List-Unsubscribe header or come from a known newsletter platform are read beyond their headers; extracted newsletter text is stored to build your decks; excerpts are sent to Anthropic's API to write cards; your mail credential is encrypted at rest; nothing is sold, shared with data brokers, or used for advertising; and deleting your account purges what we hold.

5. Third-party content, and the limits of a machine editor

Cards are written from newsletters other people wrote. We do not endorse, verify, or take responsibility for what your sources say, and we make no claim to their content beyond showing you short attributed excerpts of issues you are already a subscriber to, always with a link to the original. If you no longer want a publisher's work summarised for you, drop that sender in the app.

Cards are generated by a language model working from those issues. The system is built to make fabrication hard — a card's sources are re-checked against your own stored issues, and a card can only link to an address that appeared in the issue itself — but it is not built to make error impossible. Cards can be wrong, and can be wrong in confident-sounding prose. Use the source link before you act on anything that matters. Undertow is not financial, legal, medical or professional advice.

6. Acceptable use

Do not: resell or redistribute the decks Undertow makes for you; scrape, automate, or hammer the API; attempt to reach another user's data; reverse the service to rebuild a competing product; or connect a mailbox you have no right to. We may suspend an account that does these things, and will tell you why.

7. Availability

Undertow runs a nightly job, not a promise. Some nights produce no deck because nothing was worth reading — that is the product working. Other nights something breaks. We do not offer an uptime guarantee, and outages are not grounds for a pro-rata refund, though we will not be precious about it if the service is meaningfully broken for a meaningful time: write to us.

We may change or discontinue features. If we discontinue the service entirely, we will give you notice with enough time to export what you care about, and we will not renew subscriptions we cannot honour.

8. Your content, our software

Your mailbox content is yours. You grant us only the permission we need to run the service for you: to fetch, store, process, and send excerpts of your newsletters to the processors listed in the Privacy Policy, for the purpose of building your decks and nothing else. That permission ends when you delete your account.

The app, the server, and the editorial prompts are ours. You get a personal, non-transferable licence to use the app while your subscription is active.

9. Disclaimers and liability

To the fullest extent the law allows, Undertow is provided "as is", without warranties of any kind, and our total liability to you for any claim relating to the service is limited to the amount you paid us in the twelve months before the claim. Nothing here limits liability that cannot lawfully be limited — including, in the EEA and UK, your statutory consumer rights, and in Australia the guarantees under the Australian Consumer Law.

10. Termination

You may stop at any time: cancel the subscription with Apple and delete your account in the app. We may terminate for a material breach of section 6, or if we shut the service down.

11. Apple

Apple is not a party to this agreement. Apple has no obligation to provide support for Undertow, and no responsibility for it or its content. Apple and its subsidiaries are third-party beneficiaries of these terms and may enforce them against you. If the app fails to conform to any warranty Apple is required to give, you may notify Apple and Apple will refund the purchase price; beyond that, Apple has no warranty obligation. Claims about the app — product liability, legal non-compliance, consumer protection, intellectual property — are our responsibility, not Apple's.

12. Changes to these terms

We will change the version and effective date above, and announce a material change in the app before it takes effect. Continuing to use Undertow after that means you accept the new terms; if you do not, cancel and delete.

13. Governing law and contact

These terms are governed by the laws of the Republic of Türkiye, without regard to conflict-of-laws rules, and the courts and enforcement offices of [CITY OF THE REGISTERED OFFICE] have exclusive jurisdiction — except that if you are a consumer in the EEA or the UK, you keep the protection of the mandatory law of your country of residence and may bring proceedings there, and a consumer in Türkiye keeps the right to apply to the consumer arbitration committee or consumer court for their own place of residence.

Flapp Bilişim Anonim Şirketi · undertow@flapp.ist · [REGISTERED OFFICE ADDRESS — required for a Turkish seller under Law 6563 and the Distance Sales Regulation]