Mojiya — Privacy Policy

Last updated: 25 October 2026.

Mojiya ("the app") is a Japanese-learning app published by Mojiya Studio. This policy explains what the app does and does not do with your information.

The short version

The app shows no ads and has no analytics or trackers of its own. Everything you do — your lessons, reviews and settings — is stored on your device. You can use the free lessons without an account. If you sign in, with Google or Apple, your account also keeps a copy of your study on our server, so it is backed up and the same on each of your devices, and if you buy the course we keep a record that your account owns it so we can release the course download to you. Books, videos, subtitle files and dictionaries you import never leave your device.

What is stored, and where

• Your study data is kept on your device. Your review history, progress, settings, and any books, subtitles or dictionaries you import are stored on your device. Without an account, the app does not send them to us. With one, the study described under If you sign in is copied to our server; your books, subtitles, videos and dictionaries are not.
• Device backup (optional). If Android's backup is on, Android may include the app's progress database in the backup to your own Google account, so it can be restored on a new device. Google handles that backup under its own terms, and we never see it.
• Files you import stay on your device unless you ask otherwise. The reader and player read books, video and subtitle files locally, and do not send them to us.
  • If you turn on a library-backup switch in Settings and choose a folder (for example in Google Drive or iCloud Drive), the app copies the files you chose into that folder.
  • Your cloud provider then stores them under its own terms, on your quota, and we never see them.
  • Turning the switch off stops future copies.

Your account

You need an account to buy the course, and to back up and sync your study. You sign in with Google or Apple.

• What we store about the account. When you sign in, we store an account identifier; the identifier Google or Apple gives us; your email address, if that provider sends it; a record of which course licence the account holds and until when; and the times the account was given the course download, kept for 90 days, so one purchase cannot be downloaded without limit. We use these only to recognise you, to keep your study in sync, and to release the paid course download to your account. We do not use them for marketing.
• Purchases. Google Play processes an Android purchase, and the App Store processes an iPhone purchase, of the course subscription, the lifetime unlock and optional supporter tips. We do not receive your payment details. Purchase records are managed for us by RevenueCat, a subscription service that acts as our processor. RevenueCat receives your account identifier and the purchase records the store provides, and tells us whether your account currently owns the course.
• The course download. Downloading the course sends your account identifier to our server so it can check your licence. The download itself comes from our storage provider (Cloudflare) through a link that expires, and your device's IP address is visible to them for that request.
• Deleting your account. You can delete your account in the app (Settings → Cloud backup → Delete account) or as described at mojiya.app/delete-account.
  • Deleting it removes, at once, the account and everything our server holds for it: its sign-ins, its licence record, the course-download times, any web reminders, and the backed-up study listed below. It asks RevenueCat to delete its record of the account, and, if you signed in with Apple, tells Apple to revoke Mojiya's access.
  • The study on your device is not deleted. The app keeps it, and offers it to the next account you sign in with.
  • Google Play keeps its own record of an Android purchase, and the App Store keeps its own record of an iPhone purchase, each under its own terms.

If you sign in: backup and sync

Signing in, in the app or on this website, turns on backup and sync, and signing out turns them off. The app sends your study to our server when it opens, when you finish a session, from time to time while it is open, and when you tap Sync now, and it receives what your other devices sent.

• What the account holds.
  • Your review history: for each review, the card, when you reviewed it, how you graded it, how long it took, and how you answered — the option you chose, what you typed, the strokes you drew, how many hints you took — the typeface it was shown in, and an identifier the app makes up for each installation, so it can tell your devices apart. It is random, not your phone's serial number or advertising identifier.
  • What you bought in the in-app shop with the coins you earn by studying. No money is involved.
  • Your settings, except the few that belong to one device: the library-backup folder and its switches, the AnkiDroid note type, Reduce animations, the web pages you opened recently, and the store's customer number.
  • The words you starred, and the words you marked as known, including those an import from Anki, WaniKani or Renshuu marked.
  • Your notes.
  • The pages you bookmarked in the in-app browser: each one's address and title. The pages you visited are not sent.
  • The words you mined, each with the sentence you met it in and, when the video had one, that sentence's translation from the second subtitle track.
  • Where you are in each book, filed under a fingerprint of the book's file, not its title or its text.
  • Your placement-test results, and a record of each import from Anki, WaniKani or Renshuu: which items it matched and the review schedule it brought with them.
  • Which of your installations has synced, and when each last did.
• What it does not hold. Your books, videos, subtitle files, audiobooks, dictionaries and imported decks stay on your device. Only the words and sentences you mine reach the server, as above.
• How long it is kept. For as long as the account exists. Nothing in it is deleted on a timer, except the sign-in sessions, which go a day after they expire (after 30 days), and the course-download times, after 90 days. Once a day the server's database is copied to private storage at our storage provider (Cloudflare), and each copy is kept for 30 days, so a deleted account is gone from every copy within 30 days of its deletion.
• Who handles it for us. Our server and its database run on Railway, our hosting provider. It stores and processes the account for us and for no other purpose.
• Signing in to a different account on a device that already has progress. The app asks before it mixes two accounts, and says what each choice does:
  • Add sends this device's progress to the account you signed in to. Nothing is removed.
  • Start fresh removes the study progress, shop purchases, saved words, notes and settings from this device, apart from how the app looks, then loads the account's. It is refused while something on the device has not been backed up.
  • Cancel signs you out, and nothing changes. You can also decide later; until you do, nothing is sent or loaded.
• Seeing what is kept. Settings → Cloud backup → Export the review log shows, as text, what the account holds: its sign-ins, licence, settings and the study above, its installations, the course-download times, your reviews and your shop purchases. It does not list web reminders, described below. "Save a copy first", which the app offers before Start fresh, copies this device's review log to the clipboard, and nothing else.

On iPhone and iPad

Where this section and the rest of the policy differ, this section is what applies to the iPhone and iPad app.

• You can buy without an account. The App Store processes the purchase and keeps it with your Apple Account, and Restore brings it back. An account is asked for when you download the course audio.
• Signing in. You can sign in with Apple or with Google.
  • With Apple, the app asks Apple for no name and no email address. We keep the identifier Apple gives us and, so that we can withdraw the app's access when you delete your account (as Apple requires), Apple's sign-in token. We keep it encrypted, and use it for nothing else.
  • With Google, we keep the identifier Google gives us and your email address. Google's sign-in software in the app also collects, for Google, what Google describes in its own disclosure for that software, including your name, phone number, coarse location, identifiers and usage data, some of it for Google's analytics. That is governed by the Google Privacy Policy. It does not happen if you sign in with Apple, or do not sign in.
• Sign-in sessions. Besides what is listed under "Your account" above, the server keeps a record of each sign-in session until a day after it expires (after 30 days).
• Page lookup. Text on a manga or PDF page is read by Apple's text recognition on the device. Nothing about it is sent anywhere.
• Device backup. If iCloud Backup is on, iOS includes your progress in your own backup. The course and dictionary files are left out, because they can be downloaded again. Apple handles that backup under its own terms, and we never see it.
• Security. Your sign-in is kept in the iPhone's or iPad's Keychain, on that device only.
• Deleting your account. In the app: Settings, then Account (shown as Cloud backup), then Delete account. This deletes the account and everything above from our server at once, asks RevenueCat to delete its record, and tells Apple to withdraw the app's Sign in with Apple access. If Apple could not be reached, the app tells you how to remove it yourself: open Settings, tap your name, tap Sign in with Apple, choose Mojiya, then tap Delete. Without the app, email [email protected] with the order ID from your App Store receipt (or, for a Google account, from that Google address), and we delete it within 30 days. Our server's database is copied once a day to private storage at our storage provider (Cloudflare), and each copy is kept for 30 days, so a deleted account is gone from every copy within 30 days of its deletion.
• No tracking. The app does not track you across other companies' apps or websites, has no advertising identifier, and shows no ads.

When the app uses the internet

The free lessons work fully offline. The app goes online only for these:

• Download on a recommended dictionary in Settings fetches that dictionary directly from its publisher's website. On mojiya.app, Jiten, JMnedict and Jitendex come through our site instead, because their servers do not let a web page fetch them; the publisher then sees our site's request, not yours, and we keep nothing about it.
• Tapping an online resource on a grammar point opens that page in your browser. The app fetches nothing itself, and nothing is sent until you tap.
• Opening the purchase screen asks the store (Google Play or the App Store) and RevenueCat for the prices in your currency. RevenueCat then holds an anonymous identifier for this install, and no personal information.
• Signing in, buying, the course download, and sync talk to Google or Apple, RevenueCat and our server as described above.
• Sending a word to Anki, or tapping the picture button on a word, searches Microsoft Bing's image search for that word and downloads the picture for the card. Only the word is sent, never the sentence or the book, and only when you send or tap. Turn off "Picture from image search when none is chosen" in Settings and a send searches for nothing.
• Looking up a word on a manga or PDF page. The text is read off the page on your device by Google's ML Kit, and on Android read again by PaddleOCR, which is part of the app and sends nothing anywhere; the page never leaves your device. ML Kit sends Google diagnostics about the feature: your device's model and Android version, and the app's name and version. It does not send the page or anything you read. Google does not pass this data to third parties.
• Opening Live TV fetches the station list from our storage provider (Cloudflare). Nothing about you is sent with it. It also loads a still of each station from YouTube (i.ytimg.com), before anyone presses play. The still is not kept. Opening Watch, which is the videos on this device, does not.
• Playing a Live TV station uses YouTube API Services: it loads YouTube's own embedded player, in its privacy-enhanced mode. What YouTube collects while it plays, including any cookies or device data its player uses, is governed by the YouTube Terms of Service and the Google Privacy Policy. By playing a station you agree to be bound by the YouTube Terms of Service. The app receives no data from the player and records nothing about what you watch.

As with opening any web link, your device's IP address is visible to the server you reach. The app adds no tracking to these requests. Our own server does not write your IP address to its database or its logs; it holds it only in memory, to limit how many requests one address can make.

What the app does not do

• No advertising, and no advertising identifiers.
• No third-party analytics or tracking SDKs. The only diagnostics are ML Kit's, described above.
• No selling or sharing of personal data.
• No account unless you choose one, to buy the course or to back up your study.

The website

mojiya.app counts visits with Cloudflare Web Analytics. It sets no cookies. If you choose a light or dark theme, that choice is saved on your device and sent nowhere. A dictionary search on this site runs in your browser once its dictionary has loaded. Until then it is sent to our server to be answered; the server sees your IP address, and the word is not kept. Studying on this site keeps the study log in this browser. A browser can clear that log. If you sign in here, the session is kept in this browser tab and sent only to our server; it is not a cookie. Signing in also backs up and syncs this browser's study to your account, exactly as the app does (If you sign in, above). For each visit it records the page address, the site you came from, your country, your browser and device type, and how fast the page loaded. Cloudflare does not use your IP address or browser details to identify you or follow you across other sites, and we see only totals. Page addresses on mojiya.app never contain what you read or look up. The Android and iOS apps contain none of this.

Looking up a word on a manga or PDF page on this site reads the page in your browser, and the page is never uploaded. The first time, your browser downloads the reading models from our storage provider (Cloudflare, models.mojiya.app) and keeps them, so later visits do not download them again. Nothing about you or the page is sent with that download, though, as with any download, the server sees your IP address.

Aligning an audiobook on this site listens to it in your browser, and the audio is never uploaded. The first time, your browser downloads the speech model (about 160 MB) from our storage provider (Cloudflare, models.mojiya.app) and keeps it, so later visits do not download it again. Nothing about you or the audiobook is sent with that download, though, as with any download, the server sees your IP address.

Opening a website in the Web tab on this site sends that page's address to our server, which fetches the page, removes its scripts and sends it back. The server keeps no copy and no cookie, and does not write the address to any log; it sees your IP address, as with any request. Pages are not fetched with your sign-in or any cookie. The images and styles of a page are loaded by your browser straight from that site, which sees your IP address and your browser type. The phone apps open sites in their own web view and do not use our server for this.

Web reminders

On this site, Settings can remind you to study at your chosen hour even when Mojiya is closed. It is off until you turn it on, it needs you to be signed in, and your browser asks your permission first. The Android and iOS apps do not use any of this; their reminders are scheduled on the device.

• What we store. For each browser you turn it on in: the address your browser's push service gave for it (its endpoint), the two keys your browser made so that only it can read the message, the hour you chose, your browser's time zone (for example Asia/Jerusalem), when the next reminder is due, when the last one was sent, and a count of failed sends. It is tied to your account. It holds no study data. An account keeps up to five browsers.
• Where, and why. It is kept in our server's database (the relay, on Railway, in Postgres). We use it only to send you the reminder at your hour, and for nothing else. The reminder is a fixed line that does not say what is due. Sending it does not read your study, even when your account backs it up.
• The push service. The reminder travels through your browser's own push service: Google (Firebase Cloud Messaging) for Chrome, Edge and other Chromium browsers, Apple for Safari, Mozilla for Firefox, or Microsoft for Edge on Windows. That service sees that a message was delivered to your browser, and your IP address. The message itself is encrypted so that only your browser can read it.
• How long, and how to remove it. It is kept until one of these happens: you turn the reminder off in Settings; you sign out on this site, which unsubscribes that browser; you delete your account, which deletes every browser's record with it; your browser's push service says the subscription no longer exists; or seven sends in a row fail. Our server's daily database copies, described under deleting your account above, keep a removed record for up to 30 days.

Buying on the website

You can buy the course and the supporter tips on this site, at mojiya.app/buy. This is the only page on the site that loads a payment provider's code. The Android and iOS apps do not use it.

• Sign in first. The page sends you to sign in before it shows anything to buy, so that the purchase is recorded on your account.
• Paddle is the seller and takes the payment. The page loads code from RevenueCat (from the jsDelivr network) and from Paddle. Paddle is the seller of record and the payment processor for web purchases. Your card or other payment details are typed into Paddle's own fields and go to Paddle. They do not go to us, and we never see them. Paddle handles them under the Paddle Privacy Policy.
• RevenueCat keeps the record. As for purchases in the apps, RevenueCat is our processor for web purchases. It receives your account identifier and the purchase records, and tells us whether your account owns the course. It handles them under the RevenueCat Privacy Policy. As with any web page, jsDelivr, RevenueCat and Paddle can see your IP address and browser type when the page loads.
• Deleting your account asks RevenueCat to delete its record, as in the apps. Paddle keeps its own payment records under its own terms.

The browser extension

The Mojiya extension for Chrome, Edge, Opera, Firefox and Safari looks up Japanese on web pages and makes Anki cards. It has no ads, no analytics and no tracking, and it does not record the pages you visit.

• Looking up happens in your browser. The text you look up, the subtitles it reads from a video, and any subtitle file you drop onto a video are read by the extension on your computer and are not sent to us. On YouTube and Netflix it reads the subtitles that the site's own player downloads, and it makes no requests of its own to those sites.
• The dictionary. The first time you look something up, the extension downloads the dictionary (about 80 MB) from our server (api.mojiya.app) and keeps it in your browser. Update in its settings asks the same server for a newer copy. Nothing about you or the page is sent with these requests, though the server sees your IP address.
• Safari on iPhone and iPad. There the extension comes with the Mojiya app and asks the app's own dictionary, on your device, instead of downloading one. The text you look up goes from Safari to the app on the same device and is not sent to us.
• Anki. Adding a card sends the word, its reading and meanings, and the sentence you found it in to AnkiConnect, which runs on your own computer (127.0.0.1). A card made from a video line also carries a screenshot of the video and a few seconds of the line's audio. None of this is sent to us.
• Settings are kept in your browser's storage for extensions. If your browser syncs extension data, it syncs them under its own terms.
• Signing in is optional. If you sign the extension in to your Mojiya account, it keeps a session of its own in your browser's local storage and shows your account's email address. Signing out deletes the session. Review in Mojiya sends the word you chose, with its reading and meanings, the sentence or subtitle line it came from and that line's English if there is one, to your account, so the app can review it with you. Nothing is sent until you press it.

Security

Account traffic is encrypted in transit (HTTPS). Your sign-in token is stored in your device's encrypted keystore.

Children

The app is a general-audience learning tool and is not directed at children under 13.

Changes

When this policy changes, the date at the top changes with it.

Contact

Questions about this policy: [email protected].