SwiftUI on iOS/macOS, Kotlin on Android, WinUI 3 on Windows, GTK4 on Linux. No shared UI layer — just a common sync protocol.
The host database is merged deterministically (last-write-wins + tombstones) through a file in a folder you already sync. The payload is AES-256-GCM encrypted on the device.
Apache-2.0 license, no container, no account. Keys never leave the device unencrypted.