BasicSync

A simple app for running Syncthing on Android.

Intentionally kept basic so the project is easy to maintain. BasicSync only controls when Syncthing runs. The actual configuration is done through Syncthing's own web interface.

Features

- Android 8.0 and newer. - External storage, including SD cards and USB drives. - Android's Storage Access Framework. - Import and export of the configuration. - Pausing sync based on network and battery conditions, or on a periodic schedule. - Android's HTTP proxy settings. - Quick Settings tile to toggle between automatic and manual modes. - Optionally allows external apps to start and stop Syncthing. - Runs Syncthing as a library in the main process, so it is immune to Android 12 and newer child process restrictions. - Small additions to Syncthing's web interface, including a folder picker and a QR code scanner. - Detects and reports sync conflicts.

Usage

Download the app, grant the required permissions, and set the desired run conditions. Then open the Syncthing web interface to configure it as you would on a computer.

By default, BasicSync runs in automatic mode, starting and stopping Syncthing based on the specified run conditions. This can be overridden by selecting Manual mode in BasicSync's notification.

Permissions

- Foreground service permissions to run Syncthing in the background indefinitely. - Notifications for the sync status and for manually starting and stopping Syncthing. Unwanted notifications can be hidden by disabling the relevant channel while keeping the overall permission. - Internet access, used only to let Syncthing connect to the network. BasicSync does not and never will have ads or telemetry of its own. - Local network access on Android 17 and newer, for directly connecting to devices on the local network instead of through Syncthing's relay servers. - Read sync settings to detect if Android's auto-sync data setting is enabled. - Network state, used to detect connectivity and whether the network is unmetered. - Storage permissions, optionally used when a folder is configured for direct file access instead of using the Storage Access Framework. - Boot completed, to automatically start Syncthing after a reboot. - Battery optimization exemption, to request permission to disable battery optimizations. - Camera, optionally used for scanning a device's QR code when adding a new device. - Wi-Fi and location permissions, optionally used for stopping Syncthing unless connected to specific Wi-Fi networks. - Exact alarm permission, optionally used for the time schedule feature.

Note

Syncthing has opt-in telemetry and asks for approval before any data is sent. Syncthing's crash reporting is disabled because BasicSync integrates it in a way that is not supported upstream.

Storage Access Framework

BasicSync supports file access via Android's Storage Access Framework as an alternative to direct file access, limiting permissions to specific folders instead of all storage. However, direct file access is still recommended, because the framework is not well suited to how Syncthing accesses files. It is slower for nested paths, cannot report specific file changes, cannot guarantee filenames when multiple processes create the same file, and has a higher chance of unexpected sync errors. Because SAF support is a BasicSync feature and not a Syncthing feature, folders using SAF will not work properly if the Syncthing configuration is exported and imported into another app.

GrapheneOS users should use the OS-level storage scopes feature instead, which allows direct file access without the limitations above.

Android TV

BasicSync has basic support for Android TV. The interface is the same phone and tablet UI, so navigation may be a bit awkward, but most functionality is accessible with the TV remote's arrow keys, including Syncthing's web interface.

Limitations on Android TV include no configuration import or export, no saving logs via debug mode, and no visible notifications, since Android TV does not support notifications from third-party apps at all.

License

GNU General Public License v3.0 only