Calculowl

Privacy Policy

Effective October 15, 2026

Calculowl is a math-learning app operated by Shibby Ventures LLC ("we," "us," or "our"). It collects what it needs to run your account and track your learning, and nothing else. This policy explains what that is, who else handles it, and what you can do about it.

1. Your account

When you sign up and use Calculowl, we store:

  • Your email address, used to log you in and to send you account emails.
  • Your password, as a bcrypt hash. We never store or see the password itself.
  • Session and sign-in tokens. A session token keeps you logged in (for up to 14 days). Email-confirmation, log-in link and email-change tokens are single-purpose and expire (log-in links after 15 minutes, email-change links after 7 days).
  • Your settings: your time zone (so your daily goal resets at your midnight) and your daily XP goal.

2. Your learning data

To teach you and schedule your reviews, we store:

  • Each attempt at a problem: the topic, the problem's seed, your answer, whether it was right, hints used, time spent, any scratchpad drawing, and grading feedback (including proof gradings and disputes).
  • Your progress on each topic: mastery and the spaced-review schedule.
  • Your XP, the days you met your goal, your streak and your badges.
  • Your placement results: the topics a placement quiz marked as known.

This data is used only to run Calculowl for you. It is not used for advertising.

3. Your Anthropic API key (optional)

You can save your own Anthropic API key in Settings to turn on handwriting transcription and AI proof grading. If you do:

  • The key is stored encrypted at rest, and is used only to call Anthropic's API on your behalf.
  • When you submit a handwritten answer, the image of your handwriting is sent to Anthropic to be transcribed. When you submit a proof, the problem, its rubric and your proof (text or a handwritten image) are sent to Anthropic to be graded, along with your reason if you dispute a grade.
  • These requests are made under your key, so Anthropic's own terms and privacy policy apply to them, and Anthropic bills your account for them.
  • Removing the key in Settings stops all of this. Without a key, nothing you do in Calculowl is sent to Anthropic.

4. Email

We send account emails only: confirming your address, log-in links and email-change confirmations. They are delivered through Mailgun, so your email address and the content of those messages pass through Mailgun's service. We do not send newsletters or marketing email.

5. Cookies and local storage

Calculowl uses:

  • A session cookie, which keeps you logged in and protects forms against forgery, and a "remember me" cookie if you choose to stay logged in.
  • Your browser's local storage, for display preferences only: your theme (light or dark), whether the scratchpad is open, and whether you last typed or wrote your answer. This never leaves your device.

We do not use analytics, advertising networks, third-party trackers, or social media pixels.

6. Server logs

Like virtually all websites, our servers record basic request information (such as the page requested and the time) for security, debugging and operations. Our hosting infrastructure may also record IP addresses. These logs are not used to build profiles or track you. Our application logs are set up not to record your password, your API key, or anything sent to Anthropic.

7. Data sharing and disclosure

We do not sell, rent or share your personal information for marketing. Besides Anthropic (only under your own key) and Mailgun, Calculowl runs on third-party hosting infrastructure that processes data on our behalf strictly to deliver the service. We may disclose information if required to do so by law, regulation, legal process or enforceable governmental request, or where necessary to protect our rights, safety or property.

8. Data retention

We keep your account and learning data for as long as your account exists, so your progress is there when you come back. When your account is deleted, its tokens, attempts, progress and badges are deleted with it.

9. Security

We take reasonable measures to protect your information, including hashing passwords and encrypting API keys. However, no method of transmission over the Internet or method of electronic storage is completely secure, and we cannot guarantee absolute security.

10. Children's privacy

Calculowl is not directed to children under 13, and you must be at least 13 to create an account. We do not knowingly collect personal information from children under 13; if we learn that we have, we will delete it. If you are under 18, you may use Calculowl only with the consent of a parent or legal guardian. If you believe a child under 13 has given us personal information, please contact us and we will delete it.

11. Your choices and rights

You can change your email, password, daily goal and API key in Settings at any time. To get a copy of your data, or to have your account and all its data deleted, email [email protected] from the address on your account.

12. Changes to this policy

We may update this Privacy Policy from time to time. When we do, we will revise the "Effective" date at the top of this page. Your continued use of Calculowl after changes take effect constitutes acceptance of the updated policy.

13. Contact us

Calculowl is operated by Shibby Ventures LLC. If you have any questions about this Privacy Policy, email [email protected].