Privacy Policy

Manim Tutorial is designed to respect your privacy. You don't need an account to use the App: once a course is downloaded it plays offline, and your projects stay on your device unless you choose to send them to the optional AI assistant. We do not collect your name, email address, or other contact details, unless you choose to sign in with Google or with your email address, in which case we receive that email address (see Signing In below).

If you allow it, the App sends anonymous usage statistics and purchase records to our own server so we can understand how the App is used. You can turn this off at any time in Mine → Share anonymous usage stats.

Course videos are downloaded from our own cloud storage. To download a course, the App uses an anonymous device account, and for paid courses it sends your Google Play purchase token to our server so that the purchase can be verified with Google Play (see Course Videos below).

If you use the AI assistant, what you send it is processed by our AI service and a third-party AI model provider, as described below.

The current version of this policy is also published at https://jizuobiao.xyz/manim-tutorial/android/privacy.

We do not ask you to provide your name, email, or phone number to use the App (signing in with your email address, which shares that address with us, is optional). We do not collect the code you write, your projects, or your files, except the content you choose to send to the AI assistant. We do not include third-party advertising or tracking SDKs, we do not use your advertising ID, and we do not build an advertising profile of you.

The course list, lesson text, code and thumbnails are included in the App. The videos of the introductory lesson are included too; the videos of the other courses are downloaded when you tap Download on a course (free courses may also be downloaded automatically in the background while you are on Wi-Fi). Videos are stored in the App's private storage, are not included in device backups, and can be removed on the course page at any time.

To download a course, the App asks our server for short-lived download links and then downloads the video files from our cloud storage (Alibaba Cloud Object Storage). This request uses the anonymous device account described under AI Account & Credits below, which the App creates the first time you download a course or use the AI assistant. Our server records which course files your device account requested, together with your IP address, to operate the service and limit abuse.

Free courses do not require a purchase. For paid courses, the App sends the purchase token that Google Play issued for your "All Courses" purchase to our server, which checks it with Google Play before issuing the download links; if you are signed in and your account already owns the courses, the App may send no purchase token and our server checks your account instead. This happens whether or not usage statistics are on.

When you start using the App, you are asked to agree to this policy; if you started using the App before this feature existed, you are asked once. If you agree, the App sends the following to our server: a random identifier created for this installation of the App; when the App is opened and which screens you visit (for example the course library, a course page, the player, or the Workspace); and basic technical details — app version, Android version, device model, language setting, and that the App was installed from Google Play.

The identifier is random and is not derived from your Google account, phone number, Android ID, IMEI, or advertising ID. It is kept in the App's private storage, is not included in device backups, and is replaced if you uninstall the App or clear its data.

We use this information only to count how many devices use the App and which screens are viewed, and to improve the App. We do not sell it, use it for advertising, or share it with third parties for tracking.

Detailed event records are kept for up to 90 days and per-device daily activity for up to about 13 months; after that, only daily totals are kept. The server is operated by us and hosted on Alibaba Cloud and Tencent Cloud.

You can turn usage statistics off at any time in Mine → Share anonymous usage stats. When it is off, the App stops sending and deletes any statistics still waiting on the device.

The AI assistant is optional. Before your first request, the App asks for your consent. When you send a request, the App sends to our AI service: what you type and the images you attach; the code and file names in the current project; and frames of your renders and their error messages. It also sends the app version and language setting so the reply is in your language.

Our AI service is operated by us and hosted on Alibaba Cloud and Tencent Cloud. To generate replies, it sends this content to DeepSeek, a third-party AI model provider. We use this content only to answer your requests, to operate the service (including counting the credits each request uses and preventing abuse), and to fix problems and improve the service. We do not use it for advertising and do not sell it.

Our AI service keeps a record of each request and reply — the text you type, the project code, and the assistant's replies — so we can fix problems and check the credits each request used. Images you attach and frames of your renders are sent to the AI model but are not stored; only their format and size are recorded. These records are kept while your AI account exists and are deleted when you delete your account (see Deleting Your Account below). We do not use your code or conversations to train AI models.

The first time you download a course or use the AI assistant, the App creates an anonymous AI account for your device. It uses a random installation identifier stored in the App's private storage. This identifier is included in Android Auto Backup, so if you restore the App onto a new device, that device continues to use the same AI account and keeps its credits. It is not derived from your Google account, phone number, Android ID, or advertising ID, and it is separate from the usage-statistics identifier described above. The App also sends the app version, language setting, and Google Play billing country or region, and our server sees your IP address, which is used to limit abuse.

Our server keeps your credit balance and a record of credits added and used. When you buy AI credits, the App sends the purchase token and order identifier that Google Play issues for that purchase to our server, which checks it with Google Play so the credits can be added; this happens whether or not usage statistics are on. If a purchase is refunded, the corresponding credits are removed.

Signing in is optional and is used only to keep one account across your devices: its credit balance, monthly course credits and, where available, the courses and Workspace you bought. You can sign in with Google or with your email address; every method you add to an account opens that same account. Which methods are available is shown in the App and may change.

Sign in with Google: we receive from Google an identifier for your Google Account and the email address on it.

Email: we send a six-digit sign-in code to the address you enter. We do not send marketing email.

We use email addresses only to sign you in and to show which account you are signed in with. Our server keeps your account, the sign-in methods on it, and which devices are signed in to it. To prevent abuse, it also records which accounts each device has signed in to in the past 30 days; this record holds only a device identifier and an account identifier, and it is deleted after 30 days, even if you delete your account.

You can delete your account at any time in Mine → Account → Delete Account, after verifying with one of its sign-in methods. When you do, we remove every sign-in method on the account together with the stored identifiers and email addresses, and sign out all of its devices. The AI conversation content stored for the account's devices is deleted within 30 days, usually within 24 hours.

The credits left in the account are returned to the device you delete it from, which keeps them in an anonymous device AI account without any personal information. We keep purchase records, without any conversation content, only as needed for accounting and refunds.

If you never signed in and want the data of your device's AI account deleted, email us at byutech.cn@gmail.com.

Your learning progress — which chapters you have watched, study streak, and last position — is stored locally on your device only, so the App can show your progress and resume playback. It is not transmitted to us. Removing the App removes this data.

Code you write in the Workspace stays on your device and runs locally, unless you send it to the AI assistant as described above. AI chat history is also stored on your device.

Course videos you download are stored on your device until you remove them on the course page or uninstall the App (see Course Videos above).

In-app purchases are processed by Google Play Billing. We never see or receive your payment card details. To determine what you have unlocked, the App checks the purchase state that Google Play reports for the Google account signed in on your device. Google's handling of purchase data is governed by Google's Privacy Policy.

When you download a paid course, the App sends the purchase token of your "All Courses" purchase to our server so it can be verified with Google Play, as described under Course Videos above. If usage statistics are on, the App also sends the record Google Play provides for each purchase — the product, the purchase token, and the price shown to you — together with the installation identifier to our server, which checks it with Google Play so we can count sales and refunds. What you have unlocked never depends on this.

If you rate the App, that interaction is handled by the Google Play Store. If you choose to email us for support or feedback, we will receive the contents of your message and your email address, and will use them only to respond to you.

The App does not knowingly collect personal information from children. We do not collect names from any user, and we receive an email address only if a user chooses to sign in with email or with Google; the anonymous usage statistics described above can be turned off in Mine, and the AI assistant is used only if you agree to it.

The App relies on Google Play (Google Play Billing) for purchases, restore, ratings, and verifying purchases, and on Google Sign-In if you choose to sign in that way. The AI assistant uses DeepSeek to generate replies. Our servers are hosted on Alibaba Cloud and Tencent Cloud, and course videos are delivered from Alibaba Cloud Object Storage. Usage statistics are sent only to our own server; no third-party analytics or advertising services are integrated.

We may update this Privacy Policy from time to time. The latest version will always be available within the App and at https://jizuobiao.xyz/manim-tutorial/android/privacy.

If you have any questions about this Privacy Policy, contact us at byutech.cn@gmail.com.