北极星中文 · BeiStar Chinese

Privacy policy

Effective date: August 3, 2026

BeiStar Chinese (北极星中文) is made by BCHAN Studio LLC ("BeiStar", "we", "us"). This policy explains what information we collect when you use the BeiStar Chinese app or beistar.app, why we collect it, and what control you have over it.

The short version: we collect your email address (so you can sign in) and your learning progress (so it follows you between devices). Speaking-practice audio is scored in real time on our own servers and is not saved. There are no ads in the app, we use no analytics or tracking SDKs, and we do not sell personal information. You can delete your account and everything tied to it from inside the app at any time.

Questions about anything here: support@beistar.app.

What we collect

Your account

You can create an account three ways:

Your learning progress

Progress is tied to your account and synced to our servers so you can pick up where you left off on any device. This includes:

Practice answers and feedback

We collect the answers you give in practice exercises, including answers you type in, and quick feedback you leave, such as rating a section too easy or too hard. When you first set up the app we also ask a short survey about your background and learning goals. The survey is optional and you can skip it; it asks about your situation (for example, student or working adult), never your age or birthdate. We use all of this to improve lessons and to tune what the app shows you next.

Reports and feedback

Most screens carry a flag button for telling us something is wrong: the pinyin, the English, the audio, a fact in the text, or the app itself. Settings also has a box for anything you want to say about the app in general, good or bad.

When you send one of these we receive what you typed, and the reason you picked where the form offers a list, along with which screen you were on, which lesson, section, or word it was about, your app version, and your device platform and OS version. These reports carry no advertising identifier and nothing else that would let us follow you around. They do not carry your device model either. The crash reports described under "Diagnostics" below are the one place we receive that.

Write only what you want us to have. Neither box needs anything about you to be worth reading.

Class-card accounts get the flag and its reason list, with no text box anywhere. See "Children and school accounts" below.

Speaking practice (voice)

When you do a speaking exercise, your microphone audio is streamed to our pronunciation server, which scores it as you speak and sends back a transcript and score. The audio is processed in memory on our own server, running our own speech model. It is not written to disk, not stored in any database, and not sent to any third party. When the exercise ends, the audio is gone; the only thing kept is your numeric score and attempt count.

Your device keeps a temporary copy of the recording so you can play back your own attempt during the exercise. That file lives in the app's temporary storage and is deleted when you leave the screen.

The microphone is only active while you are doing a speaking exercise, and you can revoke microphone permission at any time in your device settings.

Purchases

Pro subscriptions are bought through the Apple App Store or Google Play. Payment runs entirely through them: we never see your card number, billing address, or payment details. We receive and store the transaction identifiers the store gives us, which we use to confirm your subscription and enable Pro on your account. Apple's and Google's own privacy policies cover the payment itself.

Diagnostics

The app may send us crash reports and basic diagnostic information, such as your device model, operating system version, and what the app was doing when something went wrong, so we can find and fix problems. Diagnostics do not include your learning content or personal information.

Crash reports go to crash-tracking software we run on our own server, and we keep them for 30 days. No third-party crash or analytics service is built into the app, so nobody outside receives them. You can turn crash reports off in Settings, under "About".

Server logs

Like nearly every online service, our servers keep routine, short-lived logs of requests (IP address, time, and what was requested) for security, debugging, and rate limiting. Rate-limit counters are held in memory and expire within an hour.

What we don't do

Service providers

A small number of companies process data for us, each for one job:

ProviderWhat it doesWhat it sees
MailgunSends account email (confirmation, password reset)Your email address and the message content
AppleSign in with Apple; subscription validationIts own sign-in and purchase data
GoogleGoogle Sign-In; subscription validationIts own sign-in and purchase data
StripeInvoicing for schools that buy class-card seatsSchool billing contacts only; individual learners never touch Stripe

That is the full list. Pronunciation scoring, progress sync, and content delivery all run on our own servers.

How long we keep things

Teachers and classrooms

If you join a classroom (through a class card or a school program), the teachers of that classroom can see your display name, seat number, and learning progress: sections completed, scores, vocabulary counts, and reading history. Teachers cannot see your email address, favorites, or settings. Teacher access is limited to their own classroom, and every time a teacher views a roster or a student's progress, that access is recorded in an audit log.

Children and school accounts

You must be at least 13 to create your own BeiStar account, and we do not knowingly collect personal information from children under 13 through self-registration. If we learn that a child under 13 has created an account, we will delete it.

Students under 13 can still use BeiStar in one way: through a class-card seat created by their school. These seats are designed to hold no personal information. There is no email, no password, no age, and no requirement to use a real name; the account is a seat number plus a display name the teacher chooses. We rely on the school to obtain any consent required for its students, acting as the school's service provider for that classroom. A school can revoke or rotate a seat at any time, which cuts off access.

A class-card seat can still flag a problem with a lesson, but it gets only the fixed list of reasons. There is no free-text box on a school seat, so there is nothing for a student to type personal information into, and our server discards any text that reaches it from one of these accounts.

Parents and guardians: if you have questions about your child's use of BeiStar through a school, start with the school, since it controls the seats. You can also reach us at support@beistar.app.

Deleting your account and data

Open the app, go to Settings, and under Account tap Manage account, then Delete account. The page that opens lists what deletion removes and what stays; deleting from there is immediate and permanent: your account, progress, vocabulary, favorites, settings, and subscription records are all removed. There is no grace period and no recovery.

If you can't get into the app, email support@beistar.app from the address on your account and we will delete it for you.

Class-card accounts are managed by the school, so the delete option is not shown there; ask your teacher or school to revoke the seat. The seat itself holds no personal contact information.

Full details, including what remains after deletion, are on the account deletion page.

Security

All traffic between the app and our servers uses TLS encryption. Passwords are stored only as bcrypt hashes, sign-in tokens are stored hashed, class-card codes are encrypted at rest, and our database is not reachable from the internet. No system is perfectly secure, but if we ever discover a breach affecting your personal information, we will notify you as the law requires.

Your choices and rights

Changes to this policy

When we change this policy we will post the new version here with a new effective date. If a change meaningfully affects how we handle your personal information, we will tell you in the app before it takes effect.

Contact

BCHAN Studio LLC
support@beistar.app
beistar.app