Privacy policy

What we collect

What you give us: the email address and display name you register with, your password (stored only as an irreversible hash, so we never see the original), the comments you post, and the order records created when you buy something.

What use of the site generates: your course progress and quiz attempts, the IP address and browser identifier attached to a login session, the interface language and pricing region you select, and your light or dark theme preference.

When you use the WeChat Mini Program, we receive the user identifiers WeChat assigns to it (openid and unionid) and use them to link your Mini Program account to your web account. We do not collect your WeChat nickname, avatar or phone number.

Cookies and local storage

Necessary: the login session cookie. Without it you cannot stay signed in, so it is not subject to a consent choice.

Preferences: your pricing region is stored in a cookie; your interface language and theme are stored in your browser local storage. They only affect how pages are shown to you and never leave your browser.

Analytics: we use Google Analytics 4 to understand which chapters get read to the end and where people get stuck. It sets cookies and records the pages you visit.

Advertising: we use Google AdSense to show ads. Google and its advertising partners use cookies and similar technologies to serve and measure those ads.

Advertising and your choices

If you visit from the European Economic Area, the United Kingdom or Switzerland, a consent dialog provided by Google appears before any ad is served, and you choose there whether to accept personalised advertising. You can change that choice at any time through the privacy settings link that dialog provides.

Wherever you are, you can turn off personalised advertising in your Google ad settings, and you can read how Google uses data from partner sites in its own documentation.

Declining personalised advertising does not remove ads and does not affect your access to course content -- the ads simply stop being selected based on your interests.

How we use it

To run the service: verify your login, decide whether you have unlocked a given course, save your progress and quiz attempts, and display and moderate comments.

To improve the content: aggregate statistics tell us which chapters need rewriting and which flows need simplifying. That analysis targets overall trends, not any particular person.

For security and legal obligations: investigating unusual logins and abuse, and keeping transaction records as accounting and law require.

We do not use your learning records or comments to train models, and we do not use them for anything unrelated to running this site.

Who we share it with

Google: advertising and website analytics (AdSense, Analytics).

Payment providers: when you buy something, payment is handled by Stripe (outside China) or WeChat Pay (in mainland China). We never see or store your card number or payment credentials.

Infrastructure providers: database and site hosting. They store and transmit data on our instructions and may not use it for their own purposes.

Legal requirements: we may disclose information where the law compels it or where it is necessary to protect the site and its users.

Beyond that we do not share your personal information, and we never sell it.

Where your data lives

Account, progress, comment and order data is stored in a managed database located in the United States. The site and its static assets are served through a global content delivery network.

This means that if you visit from mainland China or the European Economic Area, your data is transferred to and stored outside your own country or region. We rely on data processing terms agreed with our providers to safeguard those transfers.

How long we keep it

Account data is kept for as long as your account exists. When you delete your account, the associated progress, quiz attempts and comments are deleted with it.

Order and transaction records are kept for the period accounting and legal obligations require, even after account deletion.

Login session records are cleared once the session expires, and analytics data expires according to the retention setting configured in Google Analytics.

Your rights

You can ask at any time to access, correct, export or delete the personal information we hold about you, to restrict or object to certain processing, or to withdraw consent you gave earlier.

You can change your display name and delete your own comments yourself from the account page. For anything else, write to the address below and we will respond within a reasonable period.

If you are in the European Economic Area or the United Kingdom, you also have the right to complain to your local data protection authority.

Security and minors

Passwords are stored as irreversible hashes, the site and its APIs use encrypted connections throughout, and administrative actions are restricted to admin accounts. No system is perfectly secure, so please use a password here that you do not reuse elsewhere.

This site is aimed at adult learners and working engineers. It is not directed at children under 14 and we do not knowingly collect their information. If you believe we have, contact us and we will delete it.

Changes to this policy

This policy may be updated as the site changes. When something material changes we update the date at the top of this page; continuing to use the site means you accept the updated version.

Contact us

For questions about this policy, or to exercise any of the rights above, email: privacy@front-end-js.top

• Google ad settings
• How Google uses data from partner sites