Privacy Policy

Last Updated: July 26, 2026

1. Introduction

Welcome to Asoi ("we," "our," or "us"). We respect your privacy and are committed to protecting your personal data. This privacy policy explains how we collect, use, and safeguard your information when you use our website and services.

2. Information We Collect

2.1 Information You Provide to Us

  • Account Information: If you create an account, we store your email address, a username you choose, and a securely hashed password.
  • Learning Data: For signed-in users, your decks, uploaded vocabulary lists, review progress, and game statistics are stored on our servers so they are available across your devices.
  • Guest Data: Without an account, all of the above is stored only in your browser using localStorage and is never transmitted to our servers. If you later create an account, this data is copied to your account once (and removed from the browser).
  • WaniKani API Keys: If you connect a WaniKani account, your API key is stored only in that browser's localStorage and is never transmitted to or stored on our servers. Your browser talks to the WaniKani API directly, and we never see the vocabulary or progress it returns. Disconnecting from the home page removes the key. This applies whether or not you have an Asoi account.

2.2 Information Collected Automatically

Usage Data: We use Vercel Analytics and Speed Insights to collect anonymous usage data about how users interact with our website. This includes:

  • Pages visited
  • Time spent on the website
  • Browser type and version
  • Device type and screen size
  • Referring website
  • General geographic location (country/region level)

This information does not identify you personally and is used solely to improve our service and user experience.

3. How We Use Your Information

We use the information we collect to:

  • Provide, operate, and maintain our website and services
  • Improve and personalize your experience
  • Develop new features and functionality
  • Understand how our website is being used
  • Monitor and analyze usage patterns and trends
  • Prevent fraudulent use of our services

4. Data Storage and Security

4.1 Account Data

  • Account and learning data for signed-in users is stored with Supabase, our authentication and database provider.
  • Access is protected by row-level security: each account can only ever read or modify its own data.
  • You can permanently delete your account and all attached data at any time from the Settings page.

4.2 Local Storage (Guest Mode)

  • Without an account, your vocabulary lists and progress are stored locally on your device using browser localStorage.
  • This data remains on your device and is not transmitted to our servers.
  • This data persists until you clear your browser's localStorage, create an account (which moves it to your account), or use private/incognito browsing.

4.3 Analytics Data

  • Analytics data is processed and stored by Vercel, our hosting and analytics provider.
  • This data is anonymized and cannot be used to identify individual users.
  • For more information about Vercel's data practices, please see Vercel's Privacy Policy.

5. Tracking Technologies

Our website does not directly set cookies. However, our analytics providers (Vercel Analytics and Vercel Speed Insights) may use anonymous tracking mechanisms to collect usage data. This is exclusively for improving our service and understanding how users interact with our website.

We primarily use browser localStorage rather than cookies to store your preferences and data. This means:

  • Data is stored only on your device
  • Data is not automatically sent with every request (unlike cookies)
  • Data is restricted to the domain it was set on

You can clear this data at any time by clearing your browser's localStorage or using private/incognito browsing.

6. Third-Party Services

6.1 Service Providers

Our website uses the following third-party services:

  • Vercel: For hosting, analytics, and performance monitoring
  • Supabase: For account authentication and data storage

These services have their own privacy policies that govern how they use your information.

7. Your Rights

7.1 Data Control Rights

Depending on your location, you may have certain rights regarding your personal information, including:

  • The right to access information we have about you
  • The right to correct or update your personal information
  • The right to request deletion of your data
  • The right to object to or restrict processing of your data

7.2 How to Exercise Your Rights

You can exercise most of these rights yourself:

  • Delete your account and all its server-side data from the Settings page
  • Update your username from the Settings page
  • As a guest, clear your browser's localStorage to remove all local data
  • Contacting us directly for specific concerns

7.3 Email Communications

We only send you product updates or progress reminder emails if you explicitly opted in when creating your account. You can withdraw that consent at any time by contacting us. Emails required to operate your account (such as password resets) are sent regardless of this preference.

8. Children's Privacy

Our service is not directed to children under the age of 13. We do not knowingly collect personal information from children under 13. If we learn that we have collected personal information from a child under 13, we will promptly delete that information.

9. Changes to This Privacy Policy

We may update our Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page and updating the "Last Updated" date. You are advised to review this Privacy Policy periodically for any changes.

10. Contact Us

If you have any questions about this Privacy Policy, please contact us at:

Email: asoi.learn@gmail.com

11. Your Consent

By using our website, you consent to our Privacy Policy and agree to its terms.