Syncthing

Syncthing for macOS is the official native Mac menu-bar application bundle for Syncthing file synchronization. This syncthing-app Cask installs Syncthing.app with its own bundled synchronization process. It is distinct from the syncthing command-line Formula and from the core's browser-based Web GUI.

Mac controls and synchronization

The menu-bar wrapper shows synchronization status, opens shared folders in Finder, pauses devices and opens the Syncthing Web GUI in your preferred browser. It can optionally start at login, avoiding the need to separately configure a service. The bundled local instance is automatically configured. The wrapper uses Sparkle for application updates and disables the core's independent updater so the bundled components stay under one update mechanism.

Use the Web GUI to add devices, select folders and review synchronization state. Syncthing exchanges files between authorized devices without requiring a central cloud storage account. It synchronizes file creations, edits and deletions as peers become reachable. Folder modes, ignore patterns, versioning and bandwidth settings help tailor the workflow. Devices need overlapping online connectivity, directly or through a relay; the public infrastructure is not a cloud mailbox that stores all your files until every device returns.

Synchronization and backup

Syncthing is not an independent backup system. Deleting or corrupting a synchronized file can propagate to other devices, and a compromised authorized device can affect shared data. Keep a separate recoverable backup. Optional file versioning preserves selected replaced or deleted versions according to its configuration but is not a substitute for an offline or independently protected backup.

Concurrent edits can create conflict files, requiring review. Filesystem and platform differences affect permissions, symlinks and metadata; resource forks and Windows ACLs are not generally preserved. Do not assume a synchronized Mac directory is a complete system backup.

Installation and compatibility

Install the syncthing-app Homebrew Cask or mount the official DMG and drag Syncthing.app into Applications. Syncthing v2's Mac bundle requires macOS 12 Monterey or later; an older installation paragraph saying macOS 11 is superseded by the project's v2 notice and compatibility section. The bundle includes the Syncthing universal binary for Intel and Apple Silicon. Other operating systems use their appropriate core builds or integrations, not this Mac application bundle.

The official Syncthing-2.1.6-1.dmg is 28,069,114 bytes by HTTP HEAD and the published release asset size. Installed application files, indexes, retained versions and synchronized data need additional space. No separate provider, runtime or extra Cask dependency is declared. Avoid running another local Syncthing instance or wrapper against the same configuration or ports; the project explicitly warns that competing instances prevent this wrapper from working correctly.

Launch the app and configure local devices and folders, then enable Start at login only if desired. Synchronization needs its process running and the folders accessible; sleeping, offline or logged-out machines may not exchange updates. Grant macOS access to the selected folders or external volumes when required. Full Disk Access may be needed for protected locations, but should not be granted simply to synchronize an ordinary accessible folder. Firewall and local-network settings can affect discovery and connectivity.

Device authorization and privacy

Both devices must recognize each other's Device ID, and each shared folder must be accepted for the intended device. TLS protects device-to-device transfers. A Device ID is not a password, but global discovery can associate it with an external IP address. Protect the private device keys and configuration: possession can let someone impersonate the device. Revoke a lost device from its peers.

Local discovery broadcasts or multicasts a device ID and listening port on the local network. Global discovery sends device address information to discovery servers. Relays can carry traffic when a direct connection fails; file content remains end-to-end encrypted, but relay operators can see IP/device identifiers and traffic volume. These mechanisms can be disabled or configured, with connectivity trade-offs. This is not a claim that all network metadata is invisible.

The Web GUI defaults to localhost. If exposing management remotely, use the documented authentication and HTTPS protections rather than treating a device ID as GUI authorization. Usage reporting is optional and has a preview of reported fields.

Accounts, cost and licenses

The Mac wrapper and core are free to use without a mandatory subscription or centralized account. Public infrastructure and downloads do not sell a storage quota for your own synchronized folders. Third-party devices, hosting, connectivity or commercial integrations can have their own costs.

The syncthing-macos wrapper is MIT licensed, while the bundled Syncthing core uses MPL 2.0. Keep these component licenses distinct when redistributing or modifying the application. Syncthing v1's Mac bundle is deprecated and no longer receives updates; the v2 bundle is the supported line.

Official sources: Mac wrapper, Core documentation and FAQ, Security, Relaying, Wrapper MIT license, Core MPL license.