TINGDUICU

Privacy Policy

Effective date: October 4, 2026

This is the English version of the policy above (中文版). Both versions have the same content.

1. Who we are

TingduICU (Chinese name 听读ICU, website https://tingdu.icu) is a web-based English listening practice tool. It is operated by an individual developer (“the operator of TingduICU”, “we”, “us”) based in the United States. It is not a company.

This policy explains what information we collect when you use the TingduICU website and service, how we use it, where it is stored, how long we keep it, and how you can access or delete it.

2. Summary

3. Information we collect

3.1 Phone number and sign-in data

• Phone number: the number you enter to sign in. Currently only mobile numbers from mainland China, the US and Canada are supported (the US includes Puerto Rico and other US territories); numbers from other countries that share the +1 code, such as Caribbean nations, and toll-free or premium numbers are not supported. Your phone number is your account.
• Account ID: a random identifier our server assigns to each phone number. Your learning records are stored under it.
• Account dates: when the account was created and when you last signed in.
• Time zone: read from your browser the first time you sign in and used to decide when your “day” starts. You can change it in Settings.
• Sign-in tokens: a random string given to your browser after you sign in, so that you stay signed in. Your browser sends the token with every request so that the server knows it is you. The server stores each token with its phone number, creation time, last-used time, and whether that sign-in was verified by SMS.
• Verification code records: each time a code is requested, we record the phone number, the requesting IP address, the time, the purpose (sign-in or parental PIN reset), and the result. Each wrong code entered is also recorded (without the IP address). These records are used only to prevent abuse and to limit how many codes are sent.
• Verification codes: each code can be used once, is valid for 10 minutes, and stops working once it is used or expires. It is used only for that one sign-in or PIN reset. Codes for mainland China numbers and for US and Canadian numbers may be generated by our server (mainland China codes are then sent through Spug Push Assistant, and US and Canadian codes from our own US number through Twilio; see sections 6 and 7); in that case the server stores only a keyed hash (HMAC-SHA256) of the code, never the code itself, each code can be checked at most 5 times, requesting a new code cancels the previous one, and the hash record is deleted after 2 days. Otherwise, codes are generated and checked by Twilio’s verification service (Twilio Verify), and we do not store them. Codes are never written to our logs.
• SMS consent records: an SMS consent notice is shown directly below the “获取验证码” (Get code) button on the sign-in card and below the “发验证码” (Send code) button under “忘记口令？” (Forgot PIN?) in Settings; tapping the button means you agree. Each time a code is successfully sent to you, we record the phone number, the purpose (sign-in or parental PIN reset), the version of the consent notice shown on the page, when the first and the most recent code were sent under that version, the network of the requesting IP address (truncated: only the first 3 parts of an IPv4 address, for example 203.0.113.0/24, or the first 48 bits of an IPv6 address; the full IP address is not kept), and how many codes were sent. These records are used only as proof that you agreed to receive verification code texts, and are kept until your account is deleted (see section 8).

3.2 Learning records

Each time you score a sentence in Sort practice, the server stores a record: the time and date, the subtitle fingerprint and sentence number, the sentence text, the title, the clip start and end time, the sentence difficulty level, points, the number of hints, time spent, the number of loops, and similar details. We also store your daily target and whether (and when) you reached it, and “recently playing”: which subtitles you opened recently and when, one entry per person per subtitle. It is used to validate scoring and to count how many people have opened each subtitle (the operator sees only the count).

In Read-aloud practice (跟读), the server stores: the sentences picked for each day (chosen from sentences you sorted correctly, with the sentence text, subtitle fingerprint and sentence number, and title); for each attempt, the transcribed text (up to 200 characters), the score, the words you did not say clearly, whether it passed, and the length, size, and loudness of that recording (used to tell whether any sound was recorded), as well as the recording format, the recording window (the longest that attempt could record), how long transcription took, whether this device had the original audio for that sentence, and a note on any error (for example, a transcription timeout); and records of swapped sentences and system skips. The recordings themselves are not stored (see 3.9). In Daily Words (每日单词), the server stores: the words and questions for each day, each answer (the option chosen, whether it was right, whether time ran out, time taken, how many times the audio was played), and each word's progress and next review date; when a question includes a whole sentence, its source (subtitle fingerprint, sentence number, title) is recorded.

3.3 Settings

Daily target, the lock-until-target setting, loop timing, subtitle display preferences, difficulty filter, difficulty grade (“小学 / 中学 / 高中 / 大学”: elementary, middle school, high school, college), Read-aloud settings (sentences per day, pass mark, after how many failed tries in a row “换一句” (Swap) is offered, recording length), Daily Words settings (words per day, time limit per question), and time zone. The daily target, the lock, and the daily amounts for Read-aloud and Daily Words are stored as “from this day on, the value is …”, so earlier changes are kept; this lets us judge correctly whether each past day reached its target and how much was due that day. The parental PIN is stored only as a salted hash (scrypt), never in plain text. If the PIN is cleared, we record when and how the most recent clearing happened (by SMS code or by the operator); this note stays in your settings and is shown in the interface for 30 days.

3.4 Word notebook and lookup history

• Word notebook: words you add yourself (the base form and the form you clicked), the date added, and where the word came from (subtitle fingerprint, sentence number, sentence text, title, time point). Removing a word only marks it as removed; the row is kept so that we can recognize words you added before.
• Lookup history: every word you look up while signed in is recorded (while watching, and also when you click a word on the Word Notebook page), with the time, the page, and where the word came from (subtitle fingerprint, sentence number). Lookups are not recorded when you are not signed in. Lookup history is kept for 90 days. The Word Notebook page shows the words you looked up while watching (one line per word, with a count and the last date); “Clear” there deletes all of your lookup history.

3.5 Subtitle text, title, and timing

When you open a video, the website reads the embedded subtitles on your computer or phone and first sends our server a fingerprint computed from the subtitle content, to ask whether a translation already exists. Only if the server does not have these subtitles yet does the website send the subtitle text merged into sentences, the duration of each sentence, and the title. The video itself is never sent.

The title is cleaned up by the website from the file name (or from a title stored inside the video file): for example the show name, year, season, episode, and episode title. If none of these can be recognized, the title is the file name with the extension, bracketed parts, and quality tags removed. If a file name contains something you would not want others to see, rename the file before opening it.

The server stores, by fingerprint, the original subtitle text, the title, sentence durations, the AI-generated translation, notes, glossary, and sentence difficulty levels. Each subtitle is translated only once and shared site-wide: when another user opens subtitles with identical content, they see the existing translation, and may see the title that came from the first uploader's file in the “source” of a notebook word. This shared cache records the phone number of the account that first uploaded it (for usage accounting and cost control); only the operator can see it, and it is not shown to other users. We also count how many times each subtitle is opened and when it was last opened (numbers only; the marker used to count “one person, once per day” is deleted after about 2 days).

3.6 Usage statistics

For each phone number, per day: the number of AI calls and tokens used, sentences translated, sentences served from the cache, new subtitles uploaded, and similar counts, plus the time of last use. We use these for cost control and daily limits.

3.7 Access logs, application logs, and site analytics

• Access logs: the server keeps access logs (IP address, time, URL visited, browser type, and similar request details) for operations, troubleshooting, and traffic statistics. When you look up a word, the word and the subtitle fingerprint are part of the URL, so they also appear in the access logs.
• Application logs: our backend logs its activity and errors. Phone numbers in these logs are always masked (for example 138****8000), and verification codes and secret keys are never logged. The logs may contain account IDs, subtitle fingerprints, titles, the beginning of a sentence, a word added to the notebook, a word whose lookup failed, which settings were changed and their new values, or how many wrong parental PINs were entered, to help us troubleshoot.
• Site analytics: we use Umami to measure website traffic. Umami runs on our own server; it is not a third-party analytics service. With its default settings it records: the URL visited (including URL parameters) and page title, the referring URL, browser, operating system, device type, screen size, browser language, and an approximate location (country, state or province, city) derived from the IP address. It does not use cookies and is not linked to your account.

3.8 Data stored in your browser

The following is stored in this browser on this computer or phone (localStorage, sessionStorage, IndexedDB):

• Your sign-in token and phone number, to keep you signed in. Your browser sends the token to our server with every request, and the server also keeps a copy (see 3.1). Signing out clears the copy in this browser and tells the server to revoke the token.

The following stays only in your browser and is not sent to us:

• interface and playback preferences (view, layout, player settings, subtitle display, floating window position, the country code you chose at sign-in, a cache of today's progress, a marker that Read-aloud recognition is temporarily unavailable (with your account's phone number and the date; kept only in this tab and gone when you close it), whether you have visited before);
• playback history: for up to 40 recently opened videos, the file name, size, modified time, file type, when it was last opened, playback position, duration, a thumbnail, the chosen subtitle track, and a file handle provided by the browser (so you can reopen the same local file with one click);
• original audio clips for Read-aloud: when you sort a sentence correctly, the website cuts the few seconds of that sentence's audio from your own video, on your device, and stores it in the browser for the “原声” (Original) and “慢速” (Slow) buttons in Read-aloud (跟读). These clips are not uploaded. On another device, or after you clear the browser's data, they are gone (Read-aloud then uses AI reading instead).

In addition, your own Read-aloud recording of each sentence (only the latest attempt) is kept in the browser for playback (“听我的” (Play mine), “对比听” (Compare)) and discarded the next day. This copy is not uploaded; for the copy sent for transcription, see 3.9.

You can delete this data by clearing this site's data in your browser settings. We do not use cookies.

3.9 Read-aloud recordings and pronunciation audio

• Read-aloud recordings: for each attempt, the website sends that recording to our server, which passes it to OpenAI's speech recognition and scores the transcribed text. Our server does not keep the recording and does not write it to logs; it keeps only the transcribed text, the score, and the words you did not say clearly (see 3.2).
• Pronunciation of words and sentences (in the word card, the word notebook, Daily Words, and “AI 读” (AI reading) in Read-aloud): generated by our server with OpenAI's text-to-speech and cached site-wide by content, so each word or sentence is generated only once, stored on the server, and the same audio is served to everyone. OpenAI receives only the text of that word or sentence, never your phone number or account. If a word's audio is not ready yet, the word card and the notebook temporarily use your browser's built-in speech feature instead; some browsers use their vendor's online voices for this, which is handled by the browser vendor under its own policies, not by us.

4. What we do not collect

• The video file itself (picture and sound) is never uploaded; it plays only on your computer or phone.
• We do not read other files on your computer or phone, only the video you drag in or choose.
• We do not ask for your name, government ID number, home address, contacts, or precise location, and we do not collect payment information (the service is currently free).
• No ads, and no third-party advertising or tracking tools.

5. How we use information

• To sign you in, keep you signed in, and confirm that the account belongs to the holder of the phone number;
• To store and sync your progress, settings, and word notebook, so they are there when you sign in with the same number on another computer or phone;
• To translate subtitles, generate notes, rate sentence difficulty, score practice, transcribe and score Read-aloud recordings, generate pronunciation audio for words and sentences, and apply your daily target and lock;
• To prevent abuse: limiting how often and how many codes are sent, limiting daily translation volume, and controlling costs;
• To keep a record that you agreed to receive verification code texts;
• To troubleshoot, keep the service secure, improve features, and understand site traffic.

We do not sell your personal information, use it for advertising, or build marketing profiles.

6. Text messages (SMS)

7. Who we share information with

We give the service providers below only what they need to provide the service. Each processes the data under its own terms and privacy policy:

• Twilio Inc. (United States): sends SMS verification codes. Twilio receives your phone number and the message text (including the code itself); when Twilio’s verification service is used, Twilio also generates and checks the code.
• Spug Push Assistant (the company 时巴克, China): sends verification code texts to mainland China mobile numbers. Spug receives your phone number and the verification code (the code is generated and checked by our server; Spug only delivers it).
• OpenAI (United States): translates subtitles, writes notes and glossaries, rates sentence difficulty, restores normal capitalization for all-caps lines, explains sentences, and picks out the words in each sentence for Daily Words; transcribes Read-aloud recordings; and generates pronunciation audio for words and sentences. Receives the subtitle sentences and the title, each of your Read-aloud recordings, and the text of the words or sentences to be spoken. We do not send OpenAI your phone number, account ID, or anything else used to identify you; note, however, that the title is cleaned up from your file name (see 3.5), and that the recordings contain your own voice (see 3.9).
• Tencent Cloud: provides the server we rent, located in Tokyo, Japan. All server-side data (the database, subtitle cache, logs, site analytics, and backups) is stored on this server.

We may also disclose information when required by law (for example, in response to a valid legal order).

All the above categories exclude text messaging originator opt-in data and consent; this information won’t be shared with any third parties.

8. How long we keep information

“Deleted after N days” in this table means the server removes expired data during routine cleanup while it runs (for example when someone signs in, requests a code, or looks up a word), not at the exact moment it expires. When nobody is using the site, expired data may stay somewhat longer.

Backups: every day at 4:30 a.m. (Tokyo time) the server backs up the database, the sign-in and usage files, and the subtitle cache to the same server. Each backup is deleted automatically after about 15 days, so deleted data may remain in backups for up to about 15 days.

9. Children and parents

TingduICU is for anyone learning English, and children can use it too. When a child uses it:

• The account should be held by a parent (or other guardian), who signs in with the parent's phone number, so verification codes go to the parent's phone; the child uses the service with the parent's permission. The sign-in card also recommends using a parent's phone number.
• Read-aloud practice records the child's voice: each recording is used only to check how well the sentence was read and is not kept after transcription (see 3.9).
• When a child practices under a parent's account, practice records, the word notebook, and lookup history are stored under that account. The parent can see today's progress, the word notebook, and the words looked up while watching on the website; sentence-by-sentence practice records are not shown on the website at present, but the parent can email us for them. The parent can also ask us by email to delete them at any time.
• We do not ask children for their name, age, school, or similar information.
• If you learn that a child signed in with their own phone number without a parent's permission, contact us and we will delete that account's data.

10. Your choices and rights

• Access: settings, today's progress, the word notebook, and the words you looked up while watching are visible on the website. Sentence-by-sentence practice records, account details, usage, and other data are not shown on the website at present; email us for a copy.
• Correction: you can change your settings yourself. For other corrections, such as changing the phone number, email us.
• Deletion: you can clear your lookup history and remove words from the notebook at any time. To delete your whole account, there is currently no self-service button; email 80youth@gmail.com with the phone number. Once we confirm that you are the user of that number, we will delete the account, sign-in tokens, learning records (including daily results and “recently playing”), settings, word notebook, lookup history, usage statistics, verification code records, and SMS consent records, and remove your phone number from the shared subtitle cache. Copies in backups are deleted as the backups rotate, within about 15 days.
• Withdrawing SMS consent: stop requesting codes and you will receive no further messages; US and Canadian numbers can also reply STOP (after that you will not receive codes; reply START to resume, see section 6). Texts to mainland China numbers are sent through a platform and cannot be replied to with STOP.
• Signing out: “退出登录” (Sign out) in the avatar menu clears the token in this browser and tells the server to revoke it (if the network is down at that moment, the server deletes the token after 180 days without use).

We will respond as soon as we can, normally within 30 days.

11. Security

• Connections between your browser and the website use HTTPS.
• Verification codes are rate-limited. Current rules: one code per number every 120 seconds; at most 5 per number and 20 per IP address in 24 hours, plus a site-wide daily cap; each code can be checked at most 5 times; verification for a number is paused after 10 wrong codes in an hour.
• For codes generated by our server, only a keyed hash is stored, never the code itself.
• The parental PIN is stored only as a salted hash; 5 wrong PINs in a row lock PIN entry for 15 minutes.
• Phone numbers are masked in logs; verification codes and secret keys are never logged.
• On the server, the data directory and the key file have restricted permissions: only the system account that runs the service and the server administrator can read them.
• Keys for third-party services are kept on the server and never sent to browsers.

No system is perfectly secure. Your sign-in token is stored in your browser, so sign out when you finish on a shared computer or phone. If a security incident may affect your data, we will post a notice on the website.

12. Where data is stored and international transfers

• Our server is in Tokyo, Japan (Tencent Cloud). Wherever you use the service (mainland China, the United States, or elsewhere), server-side data is stored in Japan.
• For translation, sentence explanations, picking out words for Daily Words, Read-aloud transcription, and pronunciation audio, subtitle text, titles, Read-aloud recordings, and the text to be spoken are sent to OpenAI in the United States; SMS codes are sent through Twilio in the United States, and codes for mainland China numbers through Spug Push Assistant (the company 时巴克) in China, in which case your phone number and the code are transferred to mainland China.
• The operator is in the United States and accesses the server remotely from there for maintenance.

By using the service, you understand that your information is transferred to and processed in these countries. If you do not agree, please do not use the service.

13. Changes to this policy

If we change this policy, we will update the effective date at the top of this page, and we will show a notice on the website for important changes.

14. Contact us

• Email: 80youth@gmail.com
• Operator: the operator of TingduICU (individual developer, United States)
• Website: https://tingdu.icu

See also our Terms of Service.