Privacy Policy

Joker · Last updated 4 October 2026

Joker is a Japanese learning app: a chat app for friends and family that translates as you talk, so you learn Japanese vocabulary from conversations with the people you already know. This page explains what the app collects, what it does with it, and who else sees it. Joker is operated by Cheung Pak Wai, and “we” and “us” mean us.

Joker is for people aged 18 and over.

What we collect

Your account. Your nickname and email address, and either a password or an identifier from Sign in with Apple or Google Sign-In. If you use a password we store only a hashed version of it, never the password itself.

Your profile. Your nickname, a profile photo if you add one, the language you speak and the language you are learning.

Your contacts in Joker. The invite links you create and who joined through them, the people you chat with, and the group chats you are in, with their names and photos.

Joker does not ask for your location, and it does not read your phone’s address book. Before a photo you send leaves your phone, its location and other camera details are removed.

Your conversations and learning. The messages you send and receive, in one-to-one and group chats, stored both as you wrote them and as they were translated, along with reactions, replies, read state and timestamps. Also your study cards — the words you bookmark and the message each one came from, cards you make from a scan or import from Anki — your review history, which the Stats tab counts by day, and your deck settings.

Photos and stickers you send. A photo you send in a chat is stored with a smaller preview of it, and both are deleted 24 hours after you send it. A sticker is stored only as a reference — which Signal sticker pack it comes from, that pack’s public key, and which sticker in it — and the sticker packs you add to your stickers are kept with your account. We never download or store the sticker images themselves.

Your device and purchases. A notification token so we can send push notifications, a record of your in-app purchases and your remaining balance, and for each translation the AI model used, the number of tokens and what it cost.

Safety. The accounts you block, and any reports you send us.

When something goes wrong. If a request in the app fails, it sends us a short report so we can find the fault: the app and iOS versions, your device model (“iPhone 14 Pro”, not an identifier for your particular phone), which part of our API failed, the status code it returned, a brief error code, and your account id if you are signed in. It does not include the contents of your messages, your photos, your name or email, or any advertising identifier.

What we do with it

• Let you chat with the friends and family you invite.
• Translate your messages so you can hold a conversation before you are fluent.
• Send you notifications about messages and about cards due for review.
• Keep your cards, schedule your reviews, and show you how many you reviewed each day.
• Process purchases and track your balance.
• Act on blocks and reports.

Who else sees it

• Apple — Sign in with Apple, push notifications, and verifying in-app purchase receipts.
• Google — Google Sign-In, push notifications on Android, and verifying Google Play purchases.
• Amazon Web Services — profile and group photos, and the photos you send in chats, are stored on S3 and delivered through CloudFront using links that expire.

Sticker packs come straight from Signal. Joker’s stickers are Signal sticker packs. When you send, view or add a sticker, your phone downloads the pack directly from Signal’s servers (cdn-ca.signal.org), and a sticker link that does not include the pack’s key is looked up in the public directory at signalstickers.org. Those requests do not go through us, and like any website those servers see your IP address and which pack was requested. Joker is not affiliated with Signal or with signalstickers.org.

We do not sell your personal information, and we do not share it with anyone for advertising.

What stays on your phone

• Scanning text. When you photograph printed text to make cards from it, the text is read on your device using Apple’s Vision framework. The photo is not sent anywhere — only the sentences you choose to turn into cards reach us.
• Dictionary lookups. The dictionary and the furigana readings are built into the app. Tapping a word to see what it means does not contact any server.
• Pronunciation practice. This uses your microphone. Recognition runs on your device when iOS has the speech model for that language installed; if it does not, iOS sends the audio to Apple to recognise it. Either way the recording never reaches us — we receive only whether what you said matched.
• Reading aloud. The speaker button, and Auto in card review, use your phone’s own voices. Nothing is sent to read a word or a sentence, and Auto checks whether headphones are connected on your phone alone.
• Translating definitions. Dictionary definitions are translated into your language with Apple’s Translation framework, on your device.
• Exporting to Anki. The export file is made on your phone and goes wherever you choose to save or share it.

What we don’t do

Joker contains no analytics SDK, no advertising SDK and no third-party trackers. The only outside components in the app are the ones for signing in with Google, for reading Japanese text, for opening Anki files, and a few that only help draw the interface; none of them collects data for anyone else. We do not profile you for advertising, and we do not sell data to anyone.

That includes the error reports described above: they go only to our own servers, never to a third-party crash-reporting or analytics service, and they are read to fix faults rather than to measure you.

Keeping and deleting your data

You can delete your account from inside the app, under your profile. When you do, we remove your email address, name, password, Apple and Google sign-in identifiers and profile photo, delete the photo itself from storage, and sign you out everywhere. Your one-to-one conversations disappear from the other person’s chat list and can no longer be opened; group chats carry on for their other members.

To be straightforward about the part that is not erased: the messages themselves, and the words saved from them, remain in our database rather than being deleted. A conversation belongs to two people, and we do not remove one person’s side of it from the other’s account. If you want your messages removed as well, email us and we will do it.

Photos sent in chats, and their previews, are deleted from our storage 24 hours after they are sent; the message stays in the chat as an expired photo. Error reports are deleted automatically after 30 days, whether or not they were attached to an account. We keep everything else for as long as your account exists.

Your choices

• Camera and microphone permissions can be turned off at any time in iOS Settings.
• Push notifications can be turned off in iOS Settings or in the app.
• You can change or clear your profile details in the app.
• You can ask us for a copy of your data, or ask us to correct or delete it, by emailing the address below.

Security

Passwords are stored only as bcrypt hashes. Traffic between the app and our servers is encrypted in transit. Photos are served through links that expire, so a copied URL does not stay valid.

No service can promise perfect security, and we would rather say so than imply otherwise.

Children

Joker is not intended for anyone under 18, and we do not knowingly collect personal information from children. If you believe a child has created an account, email us and we will remove it.

Changes to this policy

If we change how the app handles your information, we will update this page and change the date at the top. Significant changes will also be announced in the app.

Contact

Questions about privacy, or requests about your data: hello@joker-japanese.com.