A complete, private reading progress synchronization solution for KOReader on Kindle, Kobo, Android, and other e-readers, powered by a serverless Cloudflare Worker backend (Hono + Cloudflare D1) and a non-intrusive KOReader Lua plugin.

Pair your Kindle or KOReader device in seconds without typing passwords on an e-ink keyboard:

1. On your E-Reader: Tap Tools → Sink → Pair Device (Phone/PC) to display a 6-character code (e.g., K9X 2P4).
2. On your Phone or PC: Open your Sink web dashboard and enter the code.
3. Done: Your device connects automatically and starts syncing reading progress.

• backend/ - Cloudflare Worker implementation using TypeScript, Hono, and Cloudflare D1. Includes 1-click deploy setup, pairing endpoints, and automated tests.
• sink.koplugin/ - KOReader user plugin with seamless code pairing, non-intrusive Wi-Fi management, and silent background synchronization.

Click the button below to deploy the backend to Cloudflare Workers:

Deploy via the button above, or run locally:

cd backend
npm install
npm test                # Run Vitest test suite
npm run dev             # Start local development server

1. Copy the sink.koplugin folder to your device's koreader/plugins/ directory.
2. Restart KOReader.
3. Open the top menu → Tools → Sink → Pair Device (Phone/PC).
4. Open your Worker URL on your phone or PC, enter the 6-character code and choose a 4-digit PIN, and tap Connect E-Reader.
5. Your device is now connected and reading progress will sync automatically!

GNU Affero General Public License v3.0 (AGPL-3.0). See COPYING for details.