Privacy
Last updated: 16 July 2026
Dian is a vocabulary widget app. It works quietly in the background of your phone, showing you words from your chosen languages. This page describes what data it touches, where that data lives, and what your options are.
The short version: Dian works anonymously by default and never requires you to sign up. If you choose to sign in with Google or Apple — entirely optional — Dian receives your email address from that provider. Dian doesn't track what you do across other apps or websites, and it doesn't show advertising. It stores your preferences on a server, tied either to an anonymous identifier or to your signed-in account, so they survive between sessions.
If you'd like the detail, it's below.
What Dian collects
An anonymous identifier, by default
When you first open Dian, the app creates an anonymous identifier — a random string of characters that Dian uses to tell your phone apart from anyone else's. On its own, this identifier is not connected to your name, email, phone number, contacts, location, or any other personal information. You are never required to sign in to use Dian.
If you choose to sign in
Signing in with Google or Apple is optional. If you do, Dian receives your email address from whichever provider you used, so it can identify your account, let your settings and any subscription follow you across devices, and let you manage or delete your account from within the app. Dian never sees or stores a password — Google and Apple handle the actual sign-in, and only confirm your identity and email address back to Dian.
Your language preferences and settings
To show you the right words, Dian stores your choices on its server, tied to your anonymous identifier or your signed-in account:
- Your native language
- The foreign languages you're learning (up to three)
- The difficulty level you've selected
- The themes you've chosen (e.g. travel, food, business)
- Your subscription status (free or premium)
- The date you were last active
These let your settings persist between phone restarts and let the widget show you words that match what you asked for.
Data stored only on your phone
Some things stay on your device and never leave it:
- The list of words you've saved for review
- Your interface preferences (which languages are collapsed on the word card, for example)
- Downloaded pronunciation audio clips, cached locally so the widget and app can play sound without a live connection
For words that don't yet have a pre-rendered pronunciation clip, and for example sentences, Dian falls back to your device's own built-in text-to-speech — that speech is generated on your phone and never uploaded anywhere.
Standard platform information
When you install Dian from the App Store or Google Play, Apple or Google may share standard information with Dian — things like the country your store account is in, your device model, and your OS version. This comes through each platform's normal processes. Dian doesn't have its own analytics or crash reporting beyond what Apple or Google provides by default.
What Dian does not collect
To be specific, Dian does not collect:
- Your name or phone number
- Your email address — unless you actively choose to sign in with Google or Apple
- Your location, GPS, or any sense of where you are
- Your contacts, photos, calendar, microphone, or camera
- A list of other apps on your phone
- A history of websites you visit or apps you use
- Any kind of advertising identifier (no IDFA, no fingerprinting)
- Information from third-party trackers or analytics services
- Your payment card details — Apple, Google, and RevenueCat (see below) handle payment directly; Dian never sees them
- Anything to send you marketing emails or notifications
The app doesn't ask for permissions beyond what's needed to show a widget and play audio on your device.
Where your data lives
Your settings, and your email address if you've signed in, are stored on Supabase, a database service hosted in Tokyo, Japan. Dian uses Supabase's standard authentication and database features. Supabase has its own privacy policy describing how it handles data on behalf of services like Dian.
Vocabulary content (the words, definitions, translations, and pronunciation audio) lives on the same Supabase database. This content is the same for everyone — it's not personal to you.
If you sign in, that authentication happens directly between you and Google or Apple — Dian never handles or stores your password. See Google's privacy policy or Apple's privacy policy for how each of them handles sign-in.
Subscriptions are billed through Apple's App Store or Google Play Billing, depending on your device — Dian never sees your card details. Subscription status itself is managed through RevenueCat, a subscription-management service: RevenueCat receives your anonymous identifier or account identifier so it can tell Dian whether you have an active subscription, and it does not receive your email address or any vocabulary/learning data.
Your choices
- You can use Dian without ever signing in. Everything works anonymously by default — there's no requirement to create an account or provide an email address.
- If you sign in, you can delete your account at any time. Settings → Account → Delete Account removes your email address, your preferences, and disconnects your subscription record.
- If you use Dian anonymously, you can delete your data by uninstalling the app. Because the anonymous identifier is created fresh on each install, removing the app removes the connection to your settings on the server. Reinstalling creates a new anonymous identifier and a new set of default settings.
- You can also request deletion by writing to us directly — useful if the in-app control doesn't cover your situation. Include the anonymous identifier (visible in the app's debug settings) or the email you signed in with, and we'll delete the associated data.
Children
Dian is designed for adult language learners. It is not directed at children under 13. Dian does not knowingly collect any information from children. If you believe a child has been using Dian, please contact us so we can remove any associated data.
Changes to this policy
When Dian adds new features that affect what data it touches, this policy will be updated — the "last updated" date at the top of this page will change, and meaningful changes will be reflected in the app itself before they take effect.
Contact
Questions about privacy in Dian:
We aim to respond within a few days.