Who we are

"Tiangong Box" (互为螺旋·天工匣, the "Site") is operated by an individual developer. It is an online toolbox that generates 3D-printable files in your browser. This policy explains what we collect, how we use and protect it, and your rights. For any privacy question, email hwdemtv@126.com.

What we collect

  • Account data: your email address (for login, email verification and password reset) and a password. Passwords are stored only as salted scrypt one-way hashes — nobody, including the operator, can read them.
  • Usage records: credit balance and changes, membership orders (order number, amount, status) and invite relationships. Used for bookkeeping, anti-abuse and fulfilling membership benefits.
  • Content you submit: text sent through the feedback form and any contact details you voluntarily include.

What we do NOT collect

  • Images you feed into the generators, the parameters you enter and the files you generate are processed entirely in your browser and never leave your device.
  • The Site embeds no third-party analytics, advertising or tracking scripts.

Cookies and local storage

  • Login session: a cookie keeps you signed in.
  • localStorage: remembers your light/dark theme preference and timestamps for the invite popup (throttling so it does not nag you).

None of these are used for cross-site tracking or shared with third parties.

Sharing

  • Email: verification and password-reset emails are delivered through a third-party mail service (NetEase 126); only the recipient address and the message itself are passed on.
  • Apart from the above, we never sell, rent or share your personal information.
  • If third-party payment channels are added in the future, payment is handled by the payment provider under its own privacy policy; we do not collect card details, only order number, amount and status.

Storage and security

Data is stored in the Site's server database. We apply reasonable technical measures (one-way password hashing, parameterized queries, upload type checks), but no internet transmission is absolutely secure — please also keep your credentials safe.

Minors

The Site is not directed at children under 14 and we do not knowingly collect their personal information. If this happens, contact us and we will delete it.

Retention, access and deletion

Data is kept while your account exists; after deletion requests we remove or anonymize it. To access, correct or delete your data, email hwdemtv@126.com — we usually respond within 7 days.

Changes to this policy

Updates are published on this page with a new effective date; major changes are announced prominently on the Site. See also our Terms of Service.