Syncthing keeps selected folders consistent between explicitly paired devices. Every device chooses its own local filesystem path for a shared folder, and those paths do not need to match. Paired devices exchange file state according to the folder direction and ignore rules configured on each participant.
Folder type decides which copy can change the cluster
Send & Receive accepts local and remote changes. Send Only treats its local state as the intended source, while Receive Only accepts cluster changes without publishing its own local edits. Receive Encrypted stores encrypted folder data on an untrusted device without exposing normal file contents there.
A Send Only folder can become out of sync after another device changes cluster data. Override Changes makes the Send Only copy authoritative and can overwrite or delete those remote differences. A Receive Only folder can accumulate local additions or edits that it refuses to share. Revert Local Changes removes those additions and restores changed or deleted items from the cluster.
Both buttons are destructive reconciliation actions. Choosing the wrong direction can delete the copy that the user meant to preserve. The selected Override Changes or Revert Local Changes action determines which state Syncthing restores.
Ignore rules stay local to each device
The .stignore file must sit at the root of the shared folder and use UTF-8. Its patterns use the first match. An exclamation mark negates a pattern. The (?i) prefix enables case-insensitive matching. A separate (?d) prefix lets Syncthing discard ignored content when it must delete a directory.
Syncthing does not synchronize .stignore itself. Each device needs its own copy and maintenance. Two devices can therefore share the same folder while ignoring different paths. A rule added on one computer does not silently protect the matching files on another.
Versioning protects changes received from elsewhere
Versioning starts disabled, and the user configures it per folder on each device. After the user selects a strategy, Syncthing archives files that another device’s update replaces or deletes. It does not create a version merely because the user edited the file locally on that same device.
The default archive directory is .stversions. A custom version path should remain on the same filesystem as the shared folder. Versioning on one participant does not automatically enable the same history policy on every other participant.
Shared data must not include Syncthing’s own identity
Syncthing warns against synchronizing its configuration directory. That directory holds device identity data. Copying it through synchronization can make two computers appear to have the same Device ID, which breaks the assumption that each paired device has a distinct identity.
The warning concerns Syncthing’s own configuration directory, not an ordinary shared folder. Keeping that directory outside the exchange prevents its device identity data from reaching another machine and creating a duplicate Device ID.
