Privacy Policy

Last updated: 2026-09-23

Contextia ("the tool") is a language-learning reading tool, built and run by an independent solo developer. This page explains what data we collect, how it's used, and what you can do about it. It applies to both the website and the iOS app.

What data we collect

Account info: your username and password (the password is stored encrypted — we can't see it in plain text either), your Google account ID and email if you sign in with Google, or your Apple ID's unique identifier and (if you choose to share it) your email if you sign in with Apple
Any AI provider API key you enter yourself (stored encrypted)
Articles you upload, paste, or import, and the vocabulary/sentence notes you save
Your AI feature call count and estimated cost, so you can see your own usage

How your data is used

When you use an AI feature, the content it needs is sent to a third-party AI service to generate the result: the word or sentence you select (with nearby sentences for context) for word/sentence explanations; the article text and, when word selection prioritizes your vocabulary, up to 80 words from your vocabulary list for immersion reading; the article text (up to its first ~6000 characters) for the Comprehension Quiz; public news headlines plus your reading level for AI Picks; and, if you tap "AI Summary" on a recommended article, that article's full text (fetched from its public source page) to generate the summary. Your username, email, password and other account details are never included. During the free trial this goes to DeepSeek; if you add your own key in Settings, it goes to the provider you choose there (DeepSeek / OpenAI / Anthropic Claude / Google Gemini) or to any OpenAI-compatible relay address you enter. In the iOS app, we ask for your permission before the first time anything is sent. This is the only case where your content is sent to a third party.
If you're the owner account and have enabled Google Sheets sync, your saved vocab/notes are additionally synced to your own configured Google Sheet.
If you connect Notion in Settings, your saved vocab/notes are additionally sent to the Notion page you choose, using an access token Notion issues after you authorize the connection. We only store that token (encrypted) and the ID of the page you picked — we don't see or store anything else in your Notion workspace. Disconnecting in Settings deletes the stored token immediately.
Outside of those two cases, your data is not shared with any other third party for any purpose unrelated to the tool. See "Advertising (iOS)" below for the one exception this policy carves out in advance.

Advertising (iOS)

The iOS app has Google AdMob's SDK integrated. The ad shown in this version is a Google test ad placeholder only — it doesn't come from a live ad auction and generates no advertising revenue. It's there to preview what an ad-supported version of the app would look like.

On first launch, you'll see Apple's system-level App Tracking Transparency prompt asking for your permission before any tracking-related identifier is used for ad personalization. Declining doesn't block any other feature of the app, and won't stop the test ad from showing.
Google AdMob's SDK requests this test ad from Google's servers, which involves sending device/advertising identifiers and general app usage signals, under Google's own privacy policy — the same as it would for a real ad.
When this switches from a test ad to real, revenue-generating ads, this page will be updated again in advance, and the update will be noted under "Changes to this policy" below.

Notifications (iOS)

If you allow notifications, the iOS app schedules local reminders on your device (e.g. "you have N words due for review") based on data already on your device. These are scheduled entirely on-device — nothing about your notification content or schedule is sent to us or to Apple's push servers.

Data storage and security

Account passwords are stored salted and hashed; AI keys are stored encrypted — neither is stored in plain text
Data is stored in a Postgres database hosted on Supabase
Login sessions automatically expire after 30 days and require signing in again
On iOS, a small amount of data (your saved vocabulary and reading history) is cached locally on your device so recently-viewed data is still available offline; this cache lives only on your device and follows the same account-deletion rules as your server-side data

Your rights

You can change your username and password anytime in Settings
You can contact us to request deletion of your account and data, or to export your own data
We only collect the data our features actually need, and nothing more

Changes to this policy

The tool is currently free to use; its feature scope or pricing may change in the future, and we don't promise the service will remain free forever. Any significant changes to this policy will be posted on this page, with advance notice where reasonably possible.

Contact

If you have any questions about this privacy policy, or want to delete your account or export your data, contact: johnhuangyijun2002@gmail.com