Privacy Policy

Effective date: September 5, 2026. Document version: 2026-09-05.

sitta.pro helps users read EPUB books in the original language, view AI-assisted translations, and listen to text-to-speech output. This Privacy Policy explains what information is processed, why it is processed, and what choices you have.

1. Information We Process

We process the minimum information needed to provide the reader, translation, alignment, and speech features.

• Uploaded EPUB content: EPUB files, book URLs you provide, file names, content hashes, parsed chapters, paragraph text, language information, and book metadata such as title, author, and table of contents.
• Generated reading data: translations, word alignment data, text-to-speech markup, pronunciation metadata, voice preferences, language choices, cached chapter data, and quality evaluation data needed to improve reliability of the output.
• Account and authentication data: when you sign in with Yandex ID, the service receives a Yandex account identifier and links it to an internal user identifier. The service does not receive or store your Yandex password. Access tokens may be stored in browser session storage; refresh tokens are stored in an HttpOnly cookie scoped to authentication routes.
• Usage and diagnostic data: request metadata, quota and token usage, queue status, error messages, service performance data, browser type, operating system, app version, and similar technical information used for troubleshooting and abuse prevention.
• Browser data: local storage, session storage, IndexedDB, and caches may hold settings, reading position, reading history, saved books, cached translations, offline update queues, and legal consent status.
• Analytics data: with your consent, the app may use Yandex Metrika or similar operational analytics to understand page usage, link clicks, technical errors, and product reliability. Analytics is loaded only after you choose Accept all in the in-app consent prompt and never loads if you choose Accept required only.

2. How We Use Information

• To open, parse, display, translate, align, and read EPUB content aloud.
• To save reading progress, settings, cached content, and local library entries.
• To authenticate users, manage sessions, enforce quotas, and prevent abuse.
• To operate cloud storage, queues, databases, WebSocket updates, and API routes.
• To diagnose failures, improve reliability, maintain security, and comply with legal or operational obligations.

3. Cloud and AI Processing

The service may send necessary book text, metadata, translations, and generated output to cloud and AI systems that power translation, alignment, language detection, and text-to-speech features. The current architecture uses Yandex Cloud services, including Object Storage, YDB, Message Queue, API Gateway, Yandex ID, and Yandex Responses API.

We do not use uploaded books for advertising, resale, or unrelated profiling. Processing is limited to running and improving the service, maintaining security, and resolving technical issues.

4. Cookies, Local Storage, and Caches

The app uses browser storage to keep the reader usable between sessions and offline where possible. This can include local settings, reading position, cached translations, saved EPUB files, speech preferences, and consent records.

Authentication uses browser storage and secure cookies. The long-lived refresh token is stored in an HttpOnly cookie so client-side JavaScript cannot read it. You can clear browser storage or sign out to remove local session data, although some server-side records may remain for security, quota, or operational reasons.

5. Retention and Deletion

We keep data only as long as needed to provide the service, maintain security, debug operational issues, and satisfy legal obligations. Cached or diagnostic data may be reduced, anonymized, or deleted when it is no longer needed.

You may request deletion of account-linked data or uploaded content by contacting the service operator at sitta.pro@yandex.com. Some records may be retained where required for abuse prevention, security, or legal compliance.

6. Your Choices and Rights

Depending on your location, you may have the right to request access, correction, deletion, export, restriction, or objection to certain processing. You may also withdraw optional consent where consent is the basis for processing.

Analytics is consent-based. On first load the app shows a consent prompt with two options: Accept all, which permits Yandex Metrika analytics in addition to the required functionality, and Accept required only, which keeps the app fully functional with analytics disabled. If you choose Accept required only (or decline analytics in any future consent flow), no analytics tag is loaded and no analytics processing starts.

You can manage some data directly in the browser by clearing site storage, cached files, and cookies. Clearing local data may remove saved books, settings, cached translations, and reading history from the device.

7. Security

We use reasonable technical and organizational safeguards, including access controls, HTTPS, secure cookie settings, limited token exposure, and cloud security controls. No internet service can guarantee absolute security, so you should upload only content you are authorized to process and avoid including unnecessary sensitive personal data in EPUB files.

8. Children and Sensitive Content

The service is not intended to knowingly collect personal data from children under the applicable age of digital consent without valid parental or guardian authorization. If uploaded books contain personal or sensitive information, you are responsible for ensuring that processing is lawful and appropriate.

9. International Processing

Cloud providers, authentication providers, and AI services may process data in locations different from your own. By using the service, you understand that data may be processed where the service infrastructure and providers operate, subject to applicable law.

10. Changes

We may update this Privacy Policy as the product, infrastructure, or legal requirements change. Material changes will be reflected by a new document version and, where appropriate, a renewed in-app consent prompt.

11. Contact

For privacy questions, access requests, or deletion requests, contact the service owner or operator at sitta.pro@yandex.com.