Privacy Policy

Last updated: 2026-05-19

Synthiz ("we", "us") provides a web application at synthiz.com and a companion browser extension that lets users save YouTube videos, podcasts, and web pages to their personal Synthiz memory. This policy explains what data we collect, why, and how it is protected.

1. Data we collect

1.1 Account data

• Email address (account creation, authentication, transactional emails)
• Hashed password (authentication)
• Optional profile information you choose to provide

1.2 Content you submit

• URLs and metadata of sources you save (YouTube videos, podcasts, web pages)
• YouTube transcripts you choose to capture via the browser extension
• Notes, tags, and annotations you create
• AI-generated syntheses derived from the above

1.3 Technical data

• IP address and basic request logs (security, abuse prevention)
• Session cookie (authentication only — read by the browser extension to call our API on your behalf)
• Extension preferences stored locally in your browser (e.g. the auto-capture toggle)

2. The Synthiz browser extension

The extension is designed to do only what is needed to save sources to your Synthiz memory:

• Reads the Synthiz session cookie on synthiz.com so it can authenticate API calls on your behalf. The cookie value never leaves your browser except to reach api.synthiz.com.
• Reads the URL and title of the active tab only when you click the extension button, or — if you have opted in — when you watch a YouTube video.
• Captures YouTube transcripts by reading the public transcript data YouTube exposes to your browser. This only happens on *.youtube.com and only when the auto-capture toggle is enabled in the extension popup.
• Stores extension preferences locally using the browser's storage API. Nothing in this local storage is transmitted to us.

The extension does not collect browsing history, does not track you across sites, and does not contain any third-party analytics or advertising code.

3. How we use the data

• Provide and maintain the Synthiz service (contract performance)
• Generate AI syntheses of the sources you explicitly save
• Send transactional emails (account, billing, security)
• Detect and prevent abuse (legitimate interest)
• Comply with legal obligations (accounting, lawful requests)

We do not sell your personal data to third parties. We do not use your saved content to train third-party AI models beyond what is strictly required to generate your own syntheses.

4. Sub-processors

5. Retention

• Account and content: for the duration of your subscription, plus up to 3 years after account deletion (or sooner on request).
• Billing records: 10 years (statutory accounting obligation).
• Connection logs: 12 months.

6. Your rights

Under the GDPR you have the right to access, rectify, erase, restrict, port, and object to the processing of your personal data, and to withdraw consent at any time. To exercise these rights, email contact@synthiz.com. You also have the right to lodge a complaint with your local data protection authority (in France: the CNIL — www.cnil.fr).

7. Security

• All traffic encrypted with HTTPS/TLS
• Passwords hashed with bcrypt
• Hosting in France (Scaleway), with encrypted backups
• Access to production data restricted to what is strictly necessary

8. Children

Synthiz is not directed at children under 16 and we do not knowingly collect data from them.

9. Changes

We may update this policy. Material changes will be announced by email at least 15 days before they take effect. The "Last updated" date at the top of this page always reflects the current version.

10. Contact

Email: contact@synthiz.com
See also our French-language legal pages: Politique de confidentialité, Mentions légales.