Privacy Policy

Last updated: November 1, 2026

This policy explains which personal data the Walnut iOS app and the website walnut.quizel.app process, for what purpose and on which legal basis. If this English version and the German version differ, the German version prevails.

1. Controller

Vincent Tietze. The full address is in the Impressum (legal notice).
Email for all privacy questions: quizel.support@protonmail.com

2. Your entries on the device and in iCloud

Walnut stores events, reminders, notes, note photos, topics and briefings on your device. If you are signed in to iCloud on the device, Walnut syncs them through Apple's CloudKit in your private iCloud database, so they are available on your devices. That database belongs to your Apple Account. We as the provider have no access to it. Apple's terms and privacy policy apply to iCloud.

3. Speech

The microphone is only active while you use the talk button. Apple's speech recognition turns your speech into text. Walnut runs it on the device where your language allows. Where that is not possible, Apple may process the recording on its own servers, under Apple's privacy policy. Walnut does not store audio and does not send audio to our server.

4. AI processing

When you speak an entry, the app sends to our server:

• the recognised text,
• your device's date, time, time zone and language,
• your topics and matching events, reminders and notes. For notes this can include their text, for example when you have a note restructured by voice. This lets "move the dentist" refer to the right appointment.

For the morning briefing, the app sends the day's events, reminders, short excerpts from notes and, if you entered it in the app, your first name.

Our server passes this data through the OpenRouter service to Anthropic's Claude model. The model is run by Anthropic or by a cloud provider through which OpenRouter offers it. The answer goes back to the app. Our server sets its requests so that OpenRouter only routes them to providers that, under OpenRouter's policies, neither retain them (zero data retention) nor use them for training. We do not send your IP address or an identifier of your installation to OpenRouter.

Our server keeps this content in memory only for the duration of the request. It does not store it or write it to logs.

Do not enter data you do not want to, or may not, send to an AI service, such as passwords, payment details or other people's health data.

5. Calendars, reminders, camera and notifications

Only if you allow it in iOS, Walnut reads your calendars and reminders to show them and adds new events and reminders there. This data stays on the device and in the respective calendar or reminders service, except for the transfer described in section 4. Walnut uses the camera only when you take a photo for a note yourself. Photos are not sent to our server. The app schedules notifications, such as the briefing, on your device. You can change all permissions at any time in iOS Settings.

6. Abuse prevention

To make sure only the genuine app can use our server, Walnut uses Apple's App Attest, which creates a key on your device. For each installation, our server stores:

• the public part of that key,
• a counter against replayed requests,
• the number of requests per day for usage limits.

None of this includes names or content. The server also counts requests per network by IP address. We delete these counters two days after the last request.

7. Subscriptions

Apple handles purchases and subscriptions through the App Store. We do not receive payment details. We use RevenueCat to manage subscriptions. For this, the app sends RevenueCat a random, pseudonymous identifier, purchase and subscription data, technical device data (such as device model, iOS and app version, region and language) and the IP address. Our server only asks RevenueCat whether a subscription is active for that identifier.

8. Website and support

The website walnut.quizel.app and our server run on Cloudflare. When you visit, Cloudflare processes technically necessary connection data such as IP address, time, requested address and browser identifier to deliver the content and fend off attacks. Technical logs are kept for a short time and, on our side, contain no content of your entries. The website sets no cookies and uses no analytics or advertising services.

If you email us, we process your email address and your message to handle your request. Our mailbox is hosted by Proton (Proton AG, Switzerland).

9. Purposes and legal bases

• Providing the app and its features (sections 2 to 5 and 7): Art. 6(1)(b) GDPR, because the processing is necessary for the features you use.
• Security, abuse prevention, troubleshooting and running the website (sections 6 and 8): Art. 6(1)(f) GDPR. Our legitimate interest is a secure, stable service that is not abused at others' expense.
• Support requests: Art. 6(1)(b) or (f) GDPR, depending on the request.
• Storing and accessing information on your device, such as the App Attest key: Section 25(2) no. 2 TDDDG (German Telecommunications Digital Services Data Protection Act), because this is strictly necessary for the service you request.

No automated decision-making within the meaning of Art. 22 GDPR takes place.

10. Recipients

• Apple: App Store, purchases, iCloud/CloudKit, speech recognition, App Attest
• Cloudflare, Inc.: running our server and website
• OpenRouter, Inc. and the operator of the Claude model (Anthropic or a cloud provider): AI processing under section 4
• RevenueCat, Inc.: subscription management
• Proton AG: support mailbox

Depending on the processing, these providers act as our processors or as independent controllers. Where we use a provider as a processor, the agreements required under Art. 28 GDPR apply.

11. Transfers to third countries

Some recipients process data outside the EU and EEA, in particular in the USA. We base such transfers on an adequacy decision of the European Commission, for the USA for example the EU-US Data Privacy Framework where the recipient is certified under it. Otherwise we base them on the European Commission's standard contractual clauses (Art. 46 GDPR). An adequacy decision exists for Switzerland.

12. Retention

• Entries on the device and in iCloud: until you delete them, remove the app or delete the iCloud data.
• Content for AI processing: only for the duration of the request, not stored on our server.
• App Attest data and usage counters per installation: as long as the installation uses Walnut and we need them for abuse prevention. On request we delete them earlier.
• Network counters: two days after the last request.
• Support emails: until your request is resolved, beyond that only where statutory retention duties apply.
• Apple, Cloudflare, OpenRouter, RevenueCat and Proton additionally apply their own retention periods under their terms and legal obligations.

13. Your rights

Under the GDPR you have the right of access (Art. 15), rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18) and data portability (Art. 20). You may also object to processing based on legitimate interests on grounds relating to your particular situation (Art. 21). You can lodge a complaint with a data protection supervisory authority, in particular in the EU member state where you live or work.

You manage most data yourself: delete entries in the app or together with the app, and iCloud data under Settings → your name → iCloud. For anything else, an email to the address above is enough. Because Walnut has no accounts, we may need details to match data to your installation. Never send us your Apple password.

14. Children

Walnut is not directed at children. Anyone under 16 should only use Walnut with a parent's consent.

15. Changes

We update this policy when the app, the server, our service providers or the law change. The version published here applies. The date above shows when it was last updated.