Privacy Policy

Master Mechanical Buddy by Cross University ("MMB," "we," "us") is operated by Cross Mechanical LLC. This Privacy Policy explains what we collect from users of the MMB web app, iOS app, Android app, and any related service (the "Service"); how we use it; who we share it with; and the choices you have.

Information you provide

• Account info: email address and password (hashed and salted by Supabase Auth — we never see your plain-text password).
• Profile info: your U.S. state and an optional display name.
• Ask Criss messages: the conversations you have with Criss, the study coach.
• Payment info: if you upgrade to Pro, Stripe processes your card. We never see or store full card numbers.

Information collected automatically

• Quiz and exam activity: which questions you answered, correctness, time spent.
• Device and usage info: browser type, OS, IP-derived country/region, and basic usage analytics. No third-party advertising trackers.

• To create and secure your account.
• To personalize your experience (weak-areas dashboard, Ask Criss context, state-specific code citations).
• To process payments via Stripe.
• To improve the Service. We never sell or rent your personal information.
• To send service-related emails (account recovery, billing receipts).
• To comply with law and prevent fraud.

Only the third-party processors that make the Service work:

• Supabase (database, auth) — supabase.com/privacy
• Anthropic (Ask Criss model via Claude API; Anthropic does not train on your data) — anthropic.com/legal/privacy
• Stripe (payments) — stripe.com/privacy
• Vercel (hosting) — vercel.com/legal/privacy-policy
• Apple and Google if you install the native apps.

No advertising or data brokers.

We retain your account data while your account is active. If you delete your account, we delete or anonymize your personal data within 30 days, except where law requires longer retention (e.g. payment records). We use TLS encryption in transit, encrypted storage at rest, hashed passwords, and row-level security to ensure each user can access only their own data. To delete your data, email crossmechanical22@gmail.com.

MMB is for users 18 and older preparing for professional licensing. We do not knowingly collect information from anyone under 13.

California residents (CCPA / CPRA) and EU/UK residents (GDPR) have rights to access, correct, delete, and port their data. We do not sell personal information. Contact us to exercise any right.

If you install MMB on iOS or Android and grant permission, we may send study reminders and weekly digests. You can disable these from your device settings any time.

We may update this Policy and will revise the "Last updated" date when we do. Material changes will be communicated in-app or by email. Questions: crossmechanical22@gmail.com.

Cross Mechanical LLC — Master Mechanical Buddy by Cross University