Privacy Policy
This policy explains what personal data TUH Reader (learn.tuh.education) collects, why we collect it, how long we keep it, who processes it for us, and the choices and rights you have.
At a glance
- You can use TUH Reader as a guest, without an account. Guest progress stays in your browser.
- Sign-in is with Google or Apple. We keep your learning progress on our servers only if you turn on Save progress, and you can turn it off or delete it at any time.
- When you are signed in, short answers you write (a reason for your choice, or a sentence) are checked by AI. To do this, the text is sent to our AI provider, Anthropic.
- If you buy Pro, Paddle — our Merchant of Record — takes your payment. We never see your card details; we keep only your Paddle customer and subscription identifiers, plan, status and billing dates.
- No ads, no advertising or analytics trackers, and we never sell your data.
1. Who we are
TUH Reader is operated by TUH (“TUH”, “we”, “us”), the business name 터 (TUH) of a sole proprietorship in the Republic of Korea represented by Jae Yub Kim (address and registration number: see our Terms of Service). TUH is the controller of your personal data for this service. You can reach us at [email protected].
2. What we collect and why
| Data | When | Why | Legal basis (EU/UK GDPR) |
|---|---|---|---|
| Account data — email address, name and a unique account identifier, received from Google or Apple | Only if you sign in | To create and secure your account and sign you in | Performance of a contract |
| Your answers — the answer you choose or write for each question and the time you took; if you do not save progress, also your learning record, in a locked form (section 3) | Each time you answer a question, as a guest or signed in | To check your answer on our server and choose your next questions. Unless you are signed in with Save progress on, we do not keep them on our servers: your learning record goes back to your device, locked | Performance of a contract |
| Learning progress — your course, progress, the answers you choose, the short reasons and sentences you write, how each answer was checked, time spent, cards, and when you turned on Save progress | Only if you are signed in and turn on Save progress | To keep your progress across devices, fit the next questions to you, and improve our questions | Consent — you can withdraw it at any time |
| Text checked by AI — what you write (a reason or a sentence) together with the question, the options and your answer | When you are signed in and submit a written answer | To check your answer — a core feature of the service | Performance of a contract |
| Language profile — the languages you know, your level in each, and your interface language | If you set it | To show explanations in a language you understand | Performance of a contract |
| Problem reports — question identifier, kind of problem, your optional note, app language and version, and what was on screen; linked to your account identifier if you are signed in | When you report a problem | To fix questions and the app | Legitimate interests (content quality) |
| Subscription record — your Paddle customer and subscription identifiers, the price and billing interval (month or year), status, the end of the current period and any scheduled cancellation, and whether a payment was refunded or charged back | If you buy Pro (Paddle tells our server by a signed notification) | To give you Pro, show your plan, let you manage or cancel it, and keep a record of purchases | Performance of a contract; legal obligations (records) |
| Usage counters — for each signed-in account, the number and cost of AI checks per day; the number of new questions, extra rounds and card reviews per day; the number and size of saved answer records per day; the number of times Save progress is turned on or off or progress is deleted, of profile changes and of reports per day; and the number of times checkout, subscription management or a payment-link check is opened per day. For guests, the daily number of new questions, extra rounds and card reviews is counted under a random guest identifier that our server creates and keeps inside your locked learning record | When you answer questions, review cards, use AI checking or save | To apply fair-use daily limits and control costs | Legitimate interests (fair use, abuse prevention) |
| Technical data — the IP address and browser information that reach our hosting provider when you load a page; the country derived from your IP address; when you use the app without signing in — each time you get a new question or start as a new guest, send a report or open a Paddle payment link — a one-way hash of your IP address | Every visit; as a guest: new questions, new guest starts, reports and payment links | To deliver the site securely, to offer the service only in supported regions, to apply daily limits for guests, and to limit abuse of the report form and of payment-link checks. We do not store your IP address itself. | Legitimate interests (security, abuse prevention, legal compliance) |
Our sign-in service (Amazon Cognito) holds your email address and name. Our app database keeps only your account identifier and display name. Without Save progress — as a guest, or signed in with Save progress off — our server checks each answer and chooses your next questions from a locked learning record that your device sends with each request; it sends the updated record back to your device and keeps none of it. If you turn Save progress off, text you submit for AI checking is not stored on our servers after the check.
We never receive your card or bank details: you enter them in Paddle’s checkout, which runs on Paddle’s own servers. We do not collect your precise location, contacts, camera or microphone.
3. Data stored on your device
TUH Reader uses your browser’s local storage to keep: your learning record in a locked form that only our server can open (as a guest, or signed in with Save progress off; a copy is also kept in the browser’s IndexedDB so that open tabs stay in step); the cards you have already seen and card reviews waiting to be sent, so that you can review cards offline; a note that a payment is being confirmed, for up to 24 hours after checkout; your answer to the question about adding guest progress to your account; your sign-in tokens while you are signed in; and, for guests, the languages you know. When you sign in, our sign-in service sets strictly necessary cookies on its own sign-in page to run the sign-in, and this browser tab keeps, in its session storage, a one-time security value for the sign-in and a note that you have just signed in; they are removed once used and are gone when you close the tab. If you tick Save progress and then go to sign in, this browser tab keeps a note of the course you picked and the time in its session storage, so that saving is turned on when you come back within 15 minutes; the note is removed when you come back signed in, and is gone when you close the tab.
We do not use cookies or similar technologies for advertising, analytics or cross-site tracking. You can remove data stored on your device by clearing this site’s data in your browser; progress that exists only on your device (as a guest, or with Save progress off) will then be lost.
4. AI answer checking
TUH Reader uses generative AI. When you are signed in and write a reason for your choice or a sentence with a new word, AI checks it and the app shows you the result. Guests get rule-based checking only, and no text is sent to the AI provider.
All answers are checked on our server. The app sends the answer you chose or wrote, the time you took and, for a wrong multiple-choice answer, the reason you gave (the button and any words you wrote); our server compares them with the question and with your earlier answers. For guests this check is rule-based only, and nothing is sent to the AI provider. Unless you are signed in with Save progress on, none of this is stored on our servers.
AI can make mistakes. If a result looks wrong, please use Report a problem. AI checking gives learning feedback only; it is not used to make decisions with legal or similarly significant effects on you.
Anthropic processes this text as our service provider. Under its commercial terms, Anthropic does not use it to train its models and keeps it only for a limited period (its published default is up to 30 days), unless a longer period is needed to enforce its usage policies or to comply with the law.
This notice is also our advance notice of generative AI use under Korea’s AI Basic Act (in force since 22 January 2026).
5. Who processes your data
| Provider | Role | Data | Location |
|---|---|---|---|
| Anthropic, PBC | AI answer checking | Text you submit for checking, with the question, options and your answer | United States |
| Amazon Web Services (Amazon Cognito) | Sign-in and account | Email address, name, account identifier, sign-in events | Zurich, Switzerland |
| Cloudflare, Inc. | Website hosting, app database, security | The data we store on our servers (section 2) and technical data | Global network; database in eastern North America |
| Google LLC, Apple Inc. | Sign-in providers you choose | They share your email address, name and an identifier with us; their own privacy policies apply | United States |
| Paddle.com Market Limited | Merchant of Record for Pro purchases; checkout and subscription management | Name, email, billing address, payment details and purchase history, handled under Paddle’s own privacy notice; your account identifier is attached to the purchase so that Pro reaches your account. We receive your customer and subscription identifiers and subscription status | United Kingdom |
We do not sell or rent personal data and do not share it with advertisers. We may disclose data where the law requires it.
6. International transfers
Our providers process data outside your country, including in the United States and Switzerland. The European Commission recognises Switzerland as providing adequate protection. For transfers to the United States we rely on the EU–U.S. Data Privacy Framework (and its UK and Swiss extensions) where the provider is certified, and on the European Commission’s Standard Contractual Clauses (with the UK Addendum) where needed. Contact us for a copy of the relevant safeguards.
7. How long we keep data
| Data | Kept for |
|---|---|
| Learning progress | Until you delete it, delete your account data, or ask us to delete your account |
| Answer and check history, including text you wrote | 12 months from when it was created, or less if you delete it |
| Daily AI-check counters (number and cost) | 35 days |
| Other daily counters for a signed-in account (new questions, extra rounds, card reviews, saves, profile changes, reports and payment actions — numbers only) | Up to 3 days |
| A guest’s random identifier with the daily number of new questions, extra rounds and card reviews | Up to 3 days |
| Subscription record | As a record of your purchases for as long as it is needed for tax, accounting and dispute purposes — including after you delete your account data. Paddle keeps the full payment records as the seller |
| Payment notifications from Paddle (event identifier, type and time only) | 90 days |
| Problem reports | 12 months; if you delete your account data, the report remains without a link to you |
| IP hash for guests (new questions, new guest starts, reports and payment-link checks) | Up to 3 days |
| Time of deletion after Delete my progress while signed in (account identifier, the time, and an empty record that keeps only your course, time zone, today’s extra-round count and the last date you used the app) | Until you delete your account data or ask us to delete your account |
| Deletion record after you delete your account data (account identifier and time) | 12 months, or until you turn on Save progress again |
| Language profile | Until you change it or delete your account data |
| Account (email, name, identifier) | Until you ask us to delete your account |
| Data on your device | Until you delete it in the app or clear this site’s data in your browser |
When a period ends, the data is deleted from our systems.
8. Your choices in the app
- Save progress (Me screen): turn it on or off at any time. When it is off, new progress stays on this device only, locked so that only our server can read it; progress already saved stays until you delete it.
- Delete my progress (Me screen): deletes your saved progress and your answer history from our servers, and your progress and cards from this device. If you are signed in, this works even when Save progress is off: we keep the time of deletion with your account (with an empty record), so that locked progress on your other devices is treated as empty when they next connect. As a guest, it starts a new, empty record with a new guest identifier.
- Delete my account data (Me screen): deletes everything our app database holds about you — progress, history and language profile. Usage counters from the last few days (numbers only) stay until their period in section 7 ends, so daily limits keep working. A deletion record (your account identifier and the time) stays for up to 12 months so that another device where you are still signed in cannot re-create the deleted data. Reports you sent stay without a link to you. It does not cancel a Pro subscription, and your subscription record stays as a record of purchases (section 7).
- Manage subscription (Me screen, Pro only): opens Paddle’s customer portal, where you can cancel or change your card.
- Delete your account: email [email protected] from the email address you sign in with. Your TUH sign-in account is shared by TUH services, so deleting it also removes your sign-in for other TUH services that use the same account.
- Use TUH Reader as a guest: your progress stays on this device, locked so that only our server can read it, and no text is sent for AI checking (your answers go to our server only for rule-based checking and to choose your next questions, and are not stored). Our server keeps only daily counts, for up to 3 days: under a random guest identifier, the number of new questions, extra rounds and card reviews; and under a one-way hash of your IP address, the number of new questions and new guest starts. If you send a problem report, we keep the report (without a link to any account) and count it under a one-way hash of your IP address for up to 3 days; opening a Paddle payment link is counted the same way.
9. Your rights
Depending on where you live — for example under the EU or UK GDPR, or Korea’s Personal Information Protection Act — you have the right to access your data, receive a copy in a portable format, correct it, delete it, restrict or object to its processing, and withdraw your consent at any time (withdrawal does not affect processing before it).
To use these rights, email [email protected]. We will reply within one month, or sooner where the law requires. You also have the right to complain to a data protection authority: in the EU, the authority in your country; in the UK, the Information Commissioner’s Office; in Korea, see the Korean section below.
10. Age
TUH Reader is for people aged 16 and over. If you are under 16, please do not use it. If we learn that we hold data about someone under 16, we will delete it. If you are under 18, a parent or legal guardian must agree before you buy Pro.
11. Security
All connections are encrypted (HTTPS). The learning record kept on your device, and the references to questions and cards, travel between the app and our server only as tokens that our server encrypts (AES-256-GCM), which the app cannot read or change. The text of questions and cards is sent as you see it, and the correct answer is sent only after you answer. Each account can access only its own data; only TUH’s operator can view saved learning records, for support and to improve questions. Sign-in uses a standard, secure protocol (OAuth 2.0 with PKCE), and AI checking runs only on answers to questions our server gave you, with daily limits. No system is perfectly secure; if a breach affects your data, we will notify you and the authorities as the law requires.
12. Fonts and third-party content
We host our fonts ourselves (Plus Jakarta Sans and Noto Sans KR, under the SIL Open Font License), so loading a page does not contact Google or any other font service. Our pages load no third-party scripts, with one exception: when you choose to buy Pro (or open a Paddle payment link), the app loads Paddle’s checkout script from cdn.paddle.com and shows Paddle’s checkout window. Paddle then receives your IP address and browser information, under Paddle’s privacy notice.
13. Changes to this policy
We will post any new version on this page with a new date. Before material changes take effect, we will also tell you in the app.
14. Contact
TUH · [email protected]