Privacy policy
Last updated: 16 September 2026
Yuika ("we", "us") is an app that helps you understand Japanese administrative documents. This policy explains what data we process and why.
1. Data we collect
- Account: your email address (used for magic-link sign-in).
- Documents you scan: the photo you submit and the structured understanding our AI produces (type, summary, actions, deadline, amount, glossary, confidence).
- Device id: a random id generated on your device so pre-login scans can be claimed into your account after sign-in.
- Waitlist: if you ask us to notify you about the iOS launch from our website, we store that email address (plus which page it came from and whether the browser looked like iOS or Android) until we send that announcement or you ask us to remove it. Email support@yuika.app to be taken off the list.
- Technical logs: standard server logs (timestamps, status codes) for reliability and abuse prevention. We do not sell your data.
2. How we use it
- To run the scan pipeline (send the image to our AI vision provider) and show you the result.
- To store your document history, recurrence hints and deadline insights inside the app.
- To send the magic-link email that signs you in.
- To enforce free-tier scan limits, honour Yuika Premium subscriptions (via the App Store / Google Play and RevenueCat), and protect the service from abuse.
3. AI processing
When you scan a document, Yuika sends the photograph you chose (the image bytes) to xAI, Inc. (“xAI”), which operates the Grok vision model we use to read Japanese administrative mail. We call this processor xAI Grok in the app. The image is sent so Grok can classify the document and extract what it is, what to do, the deadline and the amount. We do not send your email address, password, or other account credentials to xAI.
The iOS and Android apps ask for your explicit permission before the first scan that would share a photo with xAI. You can withdraw that permission from the profile menu (AI reading). Yuika will not send further document images to xAI until you allow it again.
Do not scan documents you are not comfortable sharing with xAI. Treat outputs as guidance, not legal or tax advice — always verify amounts and dates against the original.
4. Storage & retention
- Data is stored on our servers (currently self-hosted in the EU) with continuous encrypted backups.
- You can delete individual documents from the app at any time; that removes the record and the stored image.
- You can delete your entire account (see Delete account); we remove your user row, sessions, magic links, documents and images.
5. Sharing
We share data only with the processors needed to run the product: email delivery for magic links and waitlist confirmations; and xAI, Inc. (Grok) for document vision, after you grant in-app permission. We do not sell personal data.
6. Your rights
Depending on your location you may have rights to access, correct, export or delete your data. Use the in-app Delete account action, or email support@yuika.app.
7. Children
Yuika is not directed at children under 13 (or the minimum age in your country). Do not create an account if you are under that age.
8. Changes
We may update this policy. The "Last updated" date at the top will change; continued use after a material change means you accept the new policy.