Privacy built around a temporary reading session

S1 works without an account and keeps raw reading content out of the application database, object storage, logs, and analytics.

What happens to your data

Browser file reading

TXT and Markdown files are read locally. The original file is not uploaded to application storage.

Question generation

For custom content, normalized text and an optional title are sent once to the configured AI provider. Reviewed samples use fixed questions.

Local session data

The active session uses sessionStorage. Reader preferences and validated question cache entries use localStorage.

Short-lived derived cache

Generated questions may be cached for up to 24 hours. Raw content is not stored in that cache entry.

Anonymous protection

A signed HttpOnly cookie applies abuse limits. It does not contain article text, an IP address, or a browser fingerprint.

Safe analytics

Events contain fixed enums and metric buckets, never source text, filenames, content hashes, questions, explanations, or answers.