Terms of Service

1. Introduction and Acceptance

These Terms of Service (“these Terms”) apply to your use of NihonLetter (“the Product” or “we”). NihonLetter is an iOS app for foreign residents in Japan and multilingual families that helps you understand Japanese letters and documents.

By downloading, accessing, or using the Product, you indicate that you have read, understood, and agreed to be bound by these Terms. If you do not agree to these Terms, please do not use the Product. These Terms should be read together with our Privacy Policy.

2. Service Description

The Product helps you handle Japanese everyday letters and documents. You can scan or upload Japanese letters, documents, images, PDFs, or screenshots, and the Product performs the following processing:

• Uses OCR text recognition and AI analysis to identify the document type and extract key information (such as deadlines, amounts, and institution names).
• Generates “action cards” and offers suggested actions (the output language is determined by your app language setting: currently Simplified Chinese, Traditional Chinese, or English, with other language environments defaulting to Simplified Chinese).
• Generates deadline calendar reminders and Japanese reply templates.

The Product's output is an automated analysis result, and its accuracy, completeness, and timeliness may be affected by factors such as the quality of the original and the recognition and analysis capabilities; for use in practice, please see “Information Is for Reference Only” below.

3. Accounts and Authentication

You can use the Product or create an account in the following ways. The sign-in methods actually available follow what is shown in your app version—sign-in methods other than the anonymous account will be rolled out gradually across versions, and methods not yet released may be temporarily unavailable in your version.

• Anonymous account: can be used without registration. In this case, the session itself is the sole credential for your account. Please note in particular: if you sign out, uninstall the app, change devices, or otherwise lose that session, it may be equivalent to permanently losing that anonymous account and all its associated data, which usually cannot be recovered. If you wish to retain your account long-term, we recommend linking a sign-in method or email once the relevant method is available.
• LINE sign-in, Apple sign-in (Sign in with Apple), email Magic Link / one-time passcode (OTP) (rolled out gradually across versions): these sign-in methods will be rolled out gradually across versions; once enabled in your app version, you can sign in via any of them, and your email address will be used when signing in or linking by email.
• Linking and merging: once the relevant sign-in method is available, you can link an email to your account, or link multiple sign-in identities to the same account. We do not use phone numbers for registration or sign-in.

Account security: you should safeguard the device, email, and sign-in methods used to access your account. You are responsible for activities carried out through your account. If you find that your account is being used without authorization, please contact us promptly via our Support page.

4. Information Is for Reference Only

All output of the Product (including action cards, document-type recognition, deadline and amount extraction, suggested actions, reminders, and reply templates) is based on automated OCR and AI analysis and is for reference only. It does not constitute, and does not replace, the formal opinions, notices, or decisions of any official institution such as the city hall, the pension office, or the tax authorities, nor does it constitute legal, tax, financial, or other professional advice.

Automated analysis may contain recognition errors, omissions, or misunderstandings. For matters involving payments, filings, deadlines, legal affairs, or other important matters, please be sure to check the original and rely on the formal explanations of official institutions or the opinions of professionals. You bear the consequences of any decision made in reliance on the Product's output.

5. Acceptable Use and User Responsibilities

When using the Product, you must comply with the following requirements:

• The content you upload or process must be content you are legally entitled to, or for which you have obtained the appropriate authorization.
• You must not upload others' information or protected content that you are not entitled to process.
• You must not use the Product for any unlawful, infringing, or abusive purpose.
• You must not attempt to interfere with or disrupt the normal operation of the Product, or access the Product's systems and data without authorization.

You are responsible for the content you upload and for your use of the Product.

6. User Content and Intellectual Property

Your content belongs to you. The rights to the letters, documents, images, PDFs, and screenshots you upload, and the analysis outputs generated from them, do not transfer to us because you use the Product.

To provide the service to you, you authorize us to store, process, transmit, and analyze your content (including processing via the third-party services described below) to the extent necessary to provide, maintain, and improve the Product's features. This authorization is used only to provide the service to you, and terminates in accordance with the applicable rules after you delete the relevant content or your account.

The Product's own intellectual property. The intellectual property in the Product's software, interface, trademarks, name, design, and related content belongs to us or the respective rights holders. Without permission, you may not copy, modify, distribute, or otherwise use the foregoing.

7. Third-Party Services

To provide the service, the Product uses third-party services to the extent necessary. These third-party services are operated by their respective providers and are subject to their respective terms and policies. We share data only to the extent necessary to provide the service, and we do not sell your personal data. The relevant processors include:

• AI analysis service providers: the text extracted via OCR from your uploaded content (not the original images) is sent to the third-party AI service provider we use for processing, in order to generate recognition and analysis results—currently Anthropic (Claude), and depending on configuration possibly OpenAI or others, subject to their respective terms and policies.
• Sign-in identity providers (rolled out gradually across versions): when third-party sign-in methods such as LINE and Apple are available in your app version and you choose to use them (these methods are rolled out gradually across versions and may not yet be available in the current version), their respective terms and privacy policies will apply.
• Authentication email delivery: Magic Link and OTP emails are sent via Amazon SES (AWS).
• Storage infrastructure: data is stored on our self-hosted infrastructure (Supabase and object storage on a VPS).
• Subscriptions and in-app purchases: subscriptions and in-app purchases are handled through RevenueCat and the Apple App Store, subject to their respective terms and policies.

We are not responsible for the availability or conduct of third-party services beyond what applicable law requires. For more on how we collect and process information, please see our Privacy Policy.

8. Device Permissions

Some features of the Product require you to actively grant the relevant device permissions within the app:

• Calendar and Reminders: used to write deadline-related events to your device's calendar, or to write reminders to Reminders (via EventKit). After writing, the event / reminder identifier returned by the system is sent back to our servers to mark completion and avoid duplicates; the Product does not upload any other content from your calendar or reminders.
• Camera / Photos: used to scan or select the files you want to process.

You can manage these permissions at any time in your device's system settings. Revoking a permission may prevent the related feature from working properly.

9. User Rights and Account Deletion

You can delete your account and its associated privacy content (including files, analysis outputs, and in-app reminder records) at any time in the app via “Settings → Account → Delete Account”. Once submitted, the deletion request is processed asynchronously in the background and is usually completed within a short time. Deletion cannot be recovered.

Device calendar / reminders: events and reminders previously written to your device's local calendar or reminders via “Add to Calendar / Reminders” are local data on your device, and deleting your account does not remove them automatically; you need to delete them yourself on your device.

Retention exception: deletion removes privacy content such as your files, analysis outputs, and in-app reminder records; but to fulfill legal and compliance obligations, we de-identify finance / transaction-related records and retain them for a legally required period, and we keep one deletion audit record containing an account identifier as evidence that the deletion request was carried out. This data is used only for internal compliance purposes and is not provided externally; for details, see “Data Retention and Deletion” in our Privacy Policy.

If you cannot complete the operation in the app, you can learn how via the Delete Account page, or contact us via our Support page.

10. Disclaimer

To the maximum extent permitted by applicable law, the Product is provided on an “as is” and “as available” basis, without any express or implied warranties. We do not warrant that the Product will be uninterrupted or error-free, or that the recognition and analysis results will be entirely accurate, complete, timely, or fit for your particular purpose. Your use of the Product is at your own judgment and risk.

11. Limitation of Liability

To the maximum extent permitted by applicable law, we are not liable for any indirect, incidental, special, or consequential damages arising from the use of or inability to use the Product. These Terms do not exclude or limit liability that cannot be excluded or limited under applicable law.

12. Changes, Suspension, and Termination of the Service

We may update, change, suspend, or terminate all or part of the Product's features from time to time. We will provide necessary notice where reasonably practicable. If you violate these Terms, we may suspend or terminate your use of the Product. You may also stop using the Product and delete your account at any time.

13. Changes to These Terms

We may update these Terms. Updated Terms will be posted on this page, and the “Last updated” date at the top of the page will be updated. After the changes take effect, your continued use of the Product is deemed acceptance of the updated Terms.

14. Governing Law and Dispute Resolution

The Product is primarily intended for users in Japan, and the related processing follows the requirements of Japan's Act on the Protection of Personal Information (APPI) and the Apple App Store; if you are in another region, local laws (such as the GDPR) may also apply.

The formation, validity, interpretation, and performance of these Terms are governed by Japanese law. Any dispute arising from or relating to the Product or these Terms shall be resolved by the parties amicably and in good faith; if no agreement is reached, it shall be resolved through a channel with jurisdiction in accordance with applicable law. If you are located outside Japan, the rights granted to you by local mandatory law are not affected by this clause.

15. Paid Subscriptions and In-App Purchases

The Product may offer paid subscriptions or in-app purchases. Such purchases are completed through the Apple App Store, with RevenueCat assisting in managing subscription entitlements:

• Auto-renewal: subscriptions are of the auto-renewing type. Unless you turn off auto-renewal at least 24 hours before the end of the current subscription period, it will renew automatically for the selected period and be charged by Apple.
• Management and cancellation: you can manage or cancel your subscription at any time in your device's Apple ID account settings → Subscriptions; cancellation takes effect after the end of the current paid period, and the current paid period is generally not refunded on a pro-rata basis.
• Refunds: payment and refunds are handled by the Apple App Store according to its policies, and we generally cannot refund you directly.
• Prices and entitlements: the specific prices, subscription periods, and included entitlements follow what is shown on the in-app purchase page (paywall), and may be adjusted from time to time.

16. Contact Us

If you have any questions about these Terms, please contact us via our Support page (support@nihonletter.app).