Privacy Policy

2026-03-15

Information We Collect

We collect account information you provide during registration, including your name and email address. We also collect your learning preferences, content you submit for lesson generation, and usage data such as lesson progress and vocabulary interactions. Technical data including IP address, browser type, and device information is collected automatically when you use our service.

How We Use Your Information

We use your information to provide and improve the Duowise service, including generating personalized bilingual lessons and tracking your learning progress. Your data helps us process payments, send transactional emails, and communicate important service updates. We may also use aggregated, anonymized data to analyze usage patterns and improve the overall learning experience.

AI Data Processing and Third-Party Providers

Duowise uses artificial intelligence to generate bilingual lessons from content you submit. When you submit text for lesson generation, your input is transmitted via encrypted connection to third-party AI service providers for processing. Specifically, we use OpenRouter to access large language models (LLMs) for text analysis, translation, and lesson generation, and Inworld for text-to-speech audio synthesis.

Important: Your input data sent to these AI providers is processed solely for the purpose of generating your lesson content. It is not used to train, fine-tune, or improve any AI models. We access these services through their API interfaces, which by default do not retain or use customer data for model training.

We do not send your personal account information (name, email, password) to AI providers — only the text content you submit for lesson generation and the resulting lesson data necessary for audio synthesis.

Other Third-Party Services

In addition to AI providers, we use the following third-party services to operate Duowise: Vercel for hosting, Neon for database storage, Google for OAuth authentication, Creem for payment processing, Resend for email delivery, and PostHog for product analytics. Each third-party provider processes your data according to their own privacy policies.

Data Storage and Security

Your data is stored on secure servers with encryption in transit and at rest. We implement industry-standard security measures to protect your personal information from unauthorized access, alteration, or disclosure. However, no method of electronic storage or transmission over the internet is 100% secure, and we cannot guarantee absolute security.

Data Retention

We retain your personal data for as long as your account remains active and as needed to provide you with our services. If you delete your account, we will remove your personal data within 30 days, except where retention is required by law. Anonymized, aggregated data that cannot identify you may be retained indefinitely for analytical purposes.

Your Rights

You have the right to access, correct, and delete your personal data at any time. You can export your vocabulary and learning data, and delete your account entirely from your account settings. If you have questions about your data or wish to exercise your rights, please contact us at [email protected].

Cookies

Cookies are small text files stored on your device when you visit a website. Duowise uses cookies to provide essential functionality and, with your consent, to analyze how our service is used.

Cookies we use:

• better-auth.session_token (Essential) — Maintains your login session. Duration: browser session. Cannot be disabled.

• NEXT_LOCALE (Essential) — Stores your language preference. Duration: 1 year. Cannot be disabled.

• cookie-consent (Essential) — Records your cookie consent choice. Duration: 1 year. Cannot be disabled.

• ph_* (Analytics, optional) — PostHog analytics cookies that help us understand how users interact with Duowise. Duration: 1 year. Only set if you consent to analytics cookies.

You can manage your cookie preferences at any time using the Cookie Settings link in our website footer. You can also control cookies through your browser settings, though disabling essential cookies may affect service functionality.

Children's Privacy

Duowise is not intended for use by children under the age of 13. We do not knowingly collect personal information from children under 13. If we become aware that we have collected data from a child under 13, we will take steps to delete that information promptly.

Changes to This Policy

We may update this Privacy Policy from time to time to reflect changes in our practices or applicable laws. We will notify you of any significant changes by posting a notice on our website or sending you an email. Your continued use of Duowise after such changes constitutes acceptance of the updated policy.

Contact

If you have any questions, concerns, or requests regarding this Privacy Policy or our data practices, please contact us at [email protected]. We will respond to your inquiry within a reasonable timeframe.