Privacy Policy
The short version: We collect only what we need to run the service. We will never sell your email address or personal information to third-party advertisers. We may advertise on the platform, offer premium services, and — if you opt in — send you marketing. You're always in control.
1. Who we are
The Cunning Linguist ("we," "us," or "our") is a free language learning platform. You can reach us at hello@cunninglinguist.app.
2. What information we collect
When you create an account: If you sign up with an email address, we collect that email address and a hashed password. If you sign in with Google, we receive your name, email address, and profile picture from Google's OAuth service — we do not receive your Google password.
Usage data: We collect information about how you use the platform, including which language pairs you study, your progress through lessons, flashcard performance, quiz scores, and session activity. This data exists solely to power your personal learning experience.
Device and technical data: We collect standard server log information such as your browser type, device type, IP address, and referring URL. This is used for security monitoring and to diagnose bugs.
Local storage: Course progress for guest users is stored in your browser's localStorage. This data never leaves your device unless you create an account.
3. How we use your information
- To create and maintain your account
- To sync your learning progress across devices when you're signed in
- To improve the platform — identifying which lessons need improvement, which pairs are most used, etc.
- To send you transactional emails (account confirmation, password reset, important service updates)
- To send you marketing and product updates — only if you explicitly opt in
- To offer and manage premium services, if and when they are introduced
4. What we will never do with your email
We will never sell, rent, or trade your email address or personal information to any third-party advertiser, data broker, or marketing company. This is a firm commitment, not a technicality.
Your email is used to run your account and, if you've opted in, to communicate with you directly. That's it.
5. Advertising on the platform
The Cunning Linguist may display advertising on the platform. These ads may be served by third-party ad networks. If so, those networks may use cookies or similar technologies to serve ads based on your browsing activity — this is governed by their privacy policies, not ours. We will always aim to use advertising partners who meet reasonable privacy standards, and we will update this policy if and when advertising is introduced.
We do not share your personal account data with advertising partners. Any targeting that occurs is based on general contextual signals (e.g., what language pair you're studying), not on your name, email address, or personally identifying information.
6. Premium services
We may in the future offer premium features, subscriptions, or one-time purchases. If you make a purchase, payment is processed by a third-party payment processor (such as Stripe). We do not store your full payment card information. The payment processor's privacy policy governs how your payment data is handled.
7. Marketing communications
We may maintain an optional marketing list for product news, language tips, and promotions. You will only be added to this list if you actively opt in — for example, by checking a box during registration or separately subscribing. You can unsubscribe at any time by clicking "Unsubscribe" in any email we send, or by emailing us at hello@cunninglinguist.app.
Transactional emails (account-related, password resets, service notices) are not marketing communications and will be sent regardless of your marketing preferences.
8. Cookies
We use cookies for authentication (keeping you logged in) and session management. We may also use analytics cookies to understand how the platform is used in aggregate. We do not use third-party tracking cookies for advertising unless advertising is explicitly introduced and disclosed in an updated version of this policy.
9. Third-party services
We use the following third-party services that may process your data as part of delivering the platform:
- Google OAuth — for "Sign in with Google." Governed by Google's Privacy Policy.
- Netlify — our hosting provider. They process server logs and may store your IP address in transit.
- Supabase — our database and authentication provider. Your account data is stored on Supabase infrastructure.
10. Data retention
We retain your account data for as long as your account is active. If you delete your account, we will delete your personal information within 30 days, except where we are legally required to retain certain records.
Guest data stored in localStorage is never transmitted to our servers and is deleted when you clear your browser storage.
11. Your rights
Depending on where you are located, you may have the right to access, correct, or delete your personal data, or to object to or restrict certain processing. To exercise any of these rights, contact us at hello@cunninglinguist.app. We will respond within 30 days.
12. Children
The Cunning Linguist is not directed at children under 13 (or under 16 in certain jurisdictions). We do not knowingly collect personal information from children. If you believe a child has provided us with personal information, please contact us and we will delete it promptly.
13. Changes to this policy
We may update this policy from time to time. If we make material changes — particularly around how we use your email or introduce advertising — we will notify you by email and update the effective date at the top of this page. Continuing to use the platform after changes take effect constitutes your acceptance of the updated policy.
14. Contact
Questions, requests, or concerns about this privacy policy: hello@cunninglinguist.app
This policy was last reviewed May 2026. It is written to be readable, not just legally defensible. If something isn't clear, please ask.