Understand the Syncthing synchronization mode.

• Back to the main Syncthing section

 It also called folder type and defines how changes to files are handled between devices.  
It impacts both file behavior and permissions across the devices sharing a folder

• Under My Folders list, you can see the folder synchronization type and modify behaviors.

Send & Receive

• Both devices can modify files.
• Changes are synchronized in both directions.
• Ideal for collaborative folders.
• If conflicting changes occur, Syncthing creates a conflict copy.

Use when: You want full bidirectional sync across trusted devices.

Send Only

• The device can send changes but not receive updates from others.
• f a remote device modifies a file, Syncthing flags it as an out-of-sync item, not overwritten.
• Useful when you want to distribute a master copy.

Use when: You want to protect data from being modified by others (e.g., backup source).

Receive Only

• The device only receives changes from others.
• Any local changes are ignored and overwritten.
• Syncthing shows warnings if local files differ and offers a "revert local changes" option.

Use when: You want a read-only replica (e.g., backup target).