Privacy Policy

Last updated: July 27, 2026

This Privacy Policy describes how h15n Ventures ("we," "us," "our"), the operator of MojiMori, collects, uses, and protects your personal information when you use our Service at mojimori.app. By using the Service, you consent to the practices described in this policy.

1. Information We Collect

Information you provide

Account information: email address and password when you register, email address and Google account ID via Google Sign-In, or email address and Apple account identifier via Sign in with Apple
Native guest accounts: the iOS and Android apps can create a random local identifier so you can purchase and use Pro without registering or providing an email address. A separate random installation token is sent only during guest setup, irreversibly hashed for abuse-rate limiting, and immediately removed from the app session; it is not attached to your account or used to track activity. App Store and Google Play purchases can be restored on supported devices without registering. We collect an email only if you later choose to create an account to sync study progress or sign in on the web.
Profile information: username, language preference, timezone, and email-notification preferences
Study data: kanji and words you add to your study deck, review responses, ratings, timing, streaks, XP, and level
Payment information: if you purchase a Pro plan, your name, email, and billing details. Card numbers are submitted directly to Stripe, Apple, or Google and are not stored on our servers — we receive only the customer, transaction, or subscription references needed to manage Pro access.
Feedback: messages you submit through the feedback form

Information collected automatically

Usage data / product interaction: pages viewed, features used, study actions taken, subscription actions, and other interactions with the Service
Device information: browser type, operating system, and device type
Log data: IP address, access times, and referring URLs
Error reports: when something goes wrong, our error-monitoring service (Sentry) records the error along with technical context including IP address, user identifier, and request details
Cookies: as described in our Cookie Policy
Marketing attribution: when you arrive via a link shared on Reddit, Hacker News, a newsletter, or other distribution channels, the URL may include attribution parameters (utm_source, utm_medium, utm_campaign, utm_content). If you create an account during or after that visit, we record the channel of origin alongside your account so we can measure which channels reach learners. We do not share this with third parties and do not use it for advertising. You can request deletion of these fields by contacting us.
Visit analytics: we use the open-source Ahoy library to count page views on entity pages (kanji, words, idioms, radicals, graphemes) so we can display honest activity counts ("viewed 1,247 times this week"). Ahoy is configured cookie-free, with no GeoIP lookup, IP addresses masked at the last octet (IPv4) or last 80 bits (IPv6), and no third-party requests. Data lives in our own database and is never shared. Bot traffic is filtered out at write time.

App Store privacy label summary

For the iOS app, our App Store privacy label discloses the following six data types. "Linked" includes a random native guest profile as well as a registered account; it does not mean that a guest has supplied an email address or real-world identity.

App Store category Data type Linked to profile Used for Contact Info Email Address Yes, when provided App Functionality Other Data Customer Support Yes App Functionality Identifiers User ID Yes App Functionality and Analytics Identifiers Device ID No App Functionality, including abuse-rate limiting during guest setup Purchases Purchase History Yes App Functionality, including Pro verification and restoration Usage Data Product Interaction Yes Analytics, Product Personalization, and App Functionality

In plain language, if you choose to register, we use your email address to create and manage your account, authenticate you, send account-essential messages, and manage support. Native guest purchases do not require an email address. Feedback sent in the app is Customer Support data. The User ID is the server profile that keeps study progress and purchases together; it may identify only a random guest. Purchase History consists of the App Store or Google Play transaction and subscription references needed to verify, restore, and manage Pro access. The unlinked Device ID is the random installation token described above. We use Product Interaction data to operate MojiMori, understand which features are used, personalize study behavior and progress displays, and improve the Service.

Our Google Play Data safety disclosure uses the corresponding Android categories and purposes. Neither native app uses this data for cross-app tracking or advertising, and neither app sells personal information.

2. How We Use Your Information

We use the information we collect to:

Provide, operate, and maintain the Service
Manage your account and authenticate your identity
Process payments and manage Pro subscriptions
Calculate and schedule your spaced-repetition reviews
Track your study progress and display mastery statistics
Personalize the product experience, including study progress, review scheduling, and learning recommendations
Respond to your feedback and support requests
Send account-essential communications (e.g., password reset emails, payment receipts, the welcome message at signup) — these are required to operate the service and cannot be opted out of
Send occasional service announcements about MojiMori itself (security, downtime, policy changes, billing changes). These are operational in nature; we do not send marketing, lifecycle, or drip emails. Every announcement carries a one-click unsubscribe link and you can adjust your preference at any time at /email_preferences/unsubscribe/<token>
Monitor and analyze usage trends to improve the Service
Detect, prevent, and address technical issues and abuse
Comply with legal obligations

3. Data Sharing and Disclosure

We do not sell, rent, or trade your personal information. We share data only with the service providers listed below and in the limited circumstances after.

Service providers we use

Provider Purpose Data shared Stripe Payment processing for web Pro plans Name, email, billing address, payment method (held by Stripe, not us) Apple Payment processing for iOS in-app Pro subscriptions App Store transaction/subscription status and account-level payment handling by Apple Google Play Payment processing for Android in-app Pro subscriptions Play subscription status, purchase token, order reference, and account-level payment handling by Google Google Sign-In via Google OAuth (only if you choose this option) Email, Google account ID, profile name Sentry Error and performance monitoring IP address, user identifier, request context when errors occur Resend Delivery of transactional and broadcast emails Email address, message content Hosting provider Application and database hosting All stored data, encrypted in transit

Each provider is bound by its own data-processing terms and confidentiality obligations.

Other circumstances

Legal requirements: when we believe disclosure is necessary to comply with applicable law, regulation, legal process, or governmental request
Safety: to protect the rights, property, or safety of MojiMori, our users, or the public
Business transfers: in connection with a merger, acquisition, or sale of assets, your data may be transferred as part of that transaction

4. Data Retention

We retain your account information and study data for as long as your account is active or as needed to provide the Service. You can permanently delete a registered or automatically generated guest account inside MojiMori under Account > Data and privacy > Delete account. The in-app flow deletes the account and associated study data immediately and deletes or anonymizes other personal data, except where retention is required by law. Before deleting an account with an active web subscription, we synchronously request cancellation from our billing provider. If cancellation cannot be confirmed, no account data or billing ownership is detached and the account remains available.

Email delivery logs (records of which emails we sent you and when) are kept for up to 24 months for deliverability and audit purposes, unless you delete your account, in which case account-linked delivery logs are deleted.
Feedback messages are kept for up to 24 months so we can follow up and track recurring issues. If you delete your account, associated feedback is stripped of its email, account link, body, and technical context.
Payment and tax records are retained for the period required by applicable accounting and tax law (typically 7 years).
Deleted-account App Store recovery proof: deleting a MojiMori account does not cancel an App Store purchase. To let Apple restore that purchase to a new local guest without retaining the deleted identity, we keep only a one-way cryptographic digest of the random purchase token. It has no email, user, or transaction link and is deleted when a device-verified restore consumes it.

Legacy Sign in with Apple accounts for which MojiMori does not hold a usable Apple revocation token are still deleted immediately. After deletion, the app directs the user to Apple's official account-management instructions to revoke the remaining Sign in with Apple client access manually.

Aggregated and anonymized data that cannot be used to identify you may be retained indefinitely for analytics and research purposes.

5. Data Security

We implement industry-standard security measures to protect your personal information, including encrypted connections (TLS/SSL), secure password hashing, and access controls. However, no method of transmission over the internet or electronic storage is 100% secure, and we cannot guarantee absolute security.

6. International Data Transfers

Your data may be processed and stored in countries other than your country of residence. By using the Service, you consent to the transfer of your data to such countries, which may have different data protection laws.

7. Children's Privacy

The Service is not directed to children under 13. We do not knowingly collect personal information from children under 13. If we become aware that we have collected such information, we will take steps to delete it promptly. If you believe a child under 13 has provided us with personal information, please contact us.

8. Third-Party Links

The Service may contain links to third-party websites or services. We are not responsible for the privacy practices of those third parties. We encourage you to review their privacy policies.

9. Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of material changes by posting the updated policy on this page with a revised "last updated" date. Your continued use of the Service after changes become effective constitutes your acceptance of the updated policy.

10. Contact

MojiMori is operated by h15n Ventures. Questions about this Privacy Policy? Contact us at mojimori@h15n.com.