Effective May 10, 2026

Privacy Policy

Yatsu is designed as a local-first ebook reader. You can use the reader without creating an account. If you create a free Yatsu Account, Yatsu can sync supported Reader and Tracking settings across your devices. Book files remain on your device or in storage providers you choose.

Information Yatsu Processes

When you use Yatsu without an account, reading data such as library metadata, reader settings, highlights, bookmarks, reading progress, and cached book content is primarily stored in your browser. If you connect an external storage provider such as Google Drive or OneDrive, that provider handles its own authorization and storage under its own policies.

If you create a Yatsu Account, Yatsu processes your account identifier, email address, authentication session, and the settings data needed to provide account sign-in and settings sync. Reader appearance, layout, navigation, session, and tracking preferences can sync automatically. Data settings, books, book progress, bookmarks, highlights, reading statistics, and storage credentials are not synced by Yatsu Accounts.

Accounts and Sign-In

You can sign in with Google or with a one-time email code. Google sign-in is handled by Google Identity Services and Supabase authentication. Email code sign-in uses Supabase authentication and email delivery through Resend. Yatsu uses Cloudflare Turnstile on the email code flow to reduce automated abuse of the mailer.

Settings Sync

Settings Sync stores supported Reader and Tracking settings in Yatsu-operated Supabase storage so they can be applied when you sign in on another device. Some settings can be excluded from sync on a per-device basis. Streamer mode, which hides account identifiers in the interface for screenshots or streaming, is stored on the device where you enable it.

Discord Rich Presence Companion

Yatsu may offer an optional Windows companion app for Discord Rich Presence. If you install the companion, sign in to Yatsu, and turn Discord Rich Presence on, Yatsu sends limited reading activity from your browser to the companion over a local loopback connection on your device. This can include the current book title, whether the reader is in a reading or paused state, an elapsed timer timestamp, and a random browser session identifier used to coordinate open tabs.

The companion uses that local activity to update the Discord Desktop app through Discord's local Rich Presence interface. Discord may display this activity according to your Discord account, activity, and privacy settings. Yatsu does not send your email address, username, raw Yatsu account ID, book file, book content, bookmarks, highlights, or storage provider credentials to the companion, and Yatsu-operated servers do not store the activity sent to the companion.

Discord Rich Presence is off unless you turn it on in Yatsu. You can turn it off in Yatsu, exit the companion from the Windows tray, or adjust activity visibility in Discord. If the companion is set to start at login, that setting is controlled by you and by Windows startup settings.

Service Providers

Yatsu uses Vercel for hosting and analytics, Supabase for account authentication, sessions, and settings sync storage, Google Identity Services for Google sign-in, Resend for email code delivery, and Cloudflare Turnstile for bot and abuse protection on the email code flow. Discord is used only if you turn on the optional Discord Rich Presence companion. Microsoft Store may distribute the Windows companion app. Stripe may be used if paid features are introduced. These providers process data as needed to operate those services.

Book Content

Yatsu is intended for books and files you have the right to use. Yatsu Accounts and Settings Sync do not require uploading book files to Yatsu-operated storage. Books imported locally remain in your browser storage. Books accessed through Google Drive, OneDrive, or another storage provider remain subject to that provider's authorization and storage behavior.

Retention and Control

Local browser data can be cleared from your browser or from Yatsu's in-app controls where available. Account and sync data is retained while needed to provide the service, comply with legal obligations, prevent abuse, and support user-requested recovery or deletion. To request account or sync data deletion, contact the Yatsu maintainer through the support channel published in the app or on this website.

Changes

Yatsu may update this policy as the product changes. Material changes should be reflected on this page with a new effective date.

Contact

For privacy questions, contact the Yatsu maintainer through the support channel published in the app or on this website.