Privacy Policy

1. Information We Collect

Account data: Email address, display name, and profile photo (if you sign in with Google).

Learning data: Study session history, card review grades, response times, mastery progress, and AI tutor conversations.

Payment data: Subscription and billing information is processed by Stripe. We do not store your credit card number — Stripe handles this securely.

Technical data: Error reports (via Sentry) that may include browser type, device info, the page you were on, and other context attached to the error. We strip known sensitive fields before sending, but we do not claim these reports are anonymous.

Analytics data: Page views and page exits, plus a small set of named product events (for example: signing up, starting a first study session, finishing a demo). These carry the page address and referrer, browser and device metadata, an IP address, and a randomly generated identifier stored in your browser that lets us recognize the same browser across visits. We do not use autocapture, so individual clicks and typing are not recorded, and session replay is off.

2. How We Use Your Data

We use your data to: (a) provide and improve the learning experience; (b) schedule spaced repetition reviews; (c) power the AI tutor; (d) process payments; (e) send service-related emails (account, billing, major updates), and — only if you switch it on — a weekly summary of your progress; and (f) diagnose technical issues.

3. Third-Party Services

We share data with the following services only as needed to operate MasteryHelp:

• Firebase (Google) — authentication, database, and file storage. This is where your account, your review history and your progress are stored.
• Vercel — web hosting. Receives the request metadata any web host receives in order to serve the site.
• Stripe — payment processing
• PostHog — product analytics. Receives the analytics data described in section 1.
• Sentry — error monitoring
• Brevo — sends account emails (such as email verification) and, if you switch it on, the weekly summary email. Receives your email address and the contents of those emails, which for the weekly summary include your progress figures. Brevo counts opens and link clicks on these emails; we have set it to record them anonymously, without tying them to individual recipients.
• Anthropic — AI tutor responses on the language courses. Your messages are sent to generate replies; Anthropic does not use them to train their models, and retains them for a limited period under their own policy. The tutor is not available on Math Facts or Music Literacy, and nothing from those courses is sent to Anthropic.

Audio pronunciation files are generated ahead of time using Amazon Polly and then stored with Firebase. Nothing about your use of the app is sent to Amazon.

We do not sell personal information or use it for targeted advertising.

4. Data Retention

AI tutor conversations are deleted automatically 30 days after their last message. They exist to give the tutor continuity while a conversation is open; after that they serve no purpose.

Your account and other learning data are retained as long as your account is active. To delete your account, email hello@masteryhelp.com from the address on the account. We handle deletion requests by hand and will remove your personal data within 30 days — that covers your profile, your review history, your progress, your session logs, your AI tutor conversations, and your sign-in account.

Two things are kept: payment and invoice records held by Stripe, which we retain for accounting and tax purposes, and anonymized aggregate statistics that are not linked to you (e.g., overall usage totals).

5. Your Rights

You may: (a) request a copy of your data — we will send everything we hold about you directly (your account details, review history, progress, session logs and tutor conversations), and will pass on a request to any of the third parties in section 3 for the records they hold; (b) correct inaccurate data, including asking us to investigate and fix progress or mastery figures you believe are wrong; or (c) delete your account and data — email hello@masteryhelp.com from the address on your account for any of these, or reach us via the Support page. The weekly summary email is off unless you switch it on, and you can switch it off again at any time from your profile or with the unsubscribe link in any one of them.

6. Cookies & Local Storage

MasteryHelp uses browser storage to keep you signed in and to remember interface preferences (e.g., intro completion, last course viewed). Our analytics provider, PostHog, stores an identifier in your browser so repeat visits from the same browser can be recognized as one visitor.

We run no advertising pixels and no ad-network trackers, and we do not sell personal information or use it for targeted advertising.

7. Children's Privacy

MasteryHelp is intended for people aged 13 and over, and our Terms of Service require it. The service is currently offered only to people 13 and over, and we do not market it for use by children under 13.

We do not knowingly collect personal information from anyone under 13. Please note that the app records the activity of whoever is using an account — answers, response times, and progress — so an account should be used by the person who created it. If you believe a child under 13 has an account or has provided us with personal data, email hello@masteryhelp.com and we will delete it.

8. Changes to This Policy

We may update this policy. Material changes will be communicated via email or in-app notice. Continued use after changes constitutes acceptance.

9. Contact

Questions about your privacy? Contact us at hello@masteryhelp.com or via the Support page.