Syncthing

Syncthing keeps selected folders synchronized directly between devices without using a central file-storage service. Connections between authenticated devices are encrypted with TLS.

Your Files, Your Devices: Sync folders between supported Macs, PCs, phones, and other devices running Syncthing. Transfer time and practical file-size limits depend on your devices, network, and available storage.

Private and Secure: Communication between devices is encrypted with TLS. Relay and discovery services may help devices connect, but relays cannot read encrypted file contents. Every device has a cryptographic identity that you verify before sharing.

Simple to Set Up: Add a device by scanning a QR code or entering a short ID. Choose which folders to share. That's it — Syncthing handles the rest, including NAT traversal and relay connections when devices aren't on the same network.

Conflict Handling: When the same file changes independently on two devices, Syncthing preserves a conflict copy for you to review instead of silently choosing one version.

Established Open Source Project: Syncthing has been developed in the open for more than a decade and is supported by an active contributor community.