Syncthing — Open Source Peer-to-Peer File Synchronization

What it is

Syncthing is a continuous file synchronization tool that syncs files between devices directly, without any cloud servers or third-party accounts. All communication is encrypted with TLS, and devices authenticate each other using unique device IDs. Syncthing is open source, decentralized, and works on Linux, macOS, Windows, Android, and FreeBSD.

Syncthing is designed for privacy-conscious users and teams who want to sync files across devices without trusting cloud providers with their data.

How it saves time or tokens

Cloud sync services (Dropbox, Google Drive) require accounts, have storage limits, and store your data on third-party servers. Syncthing eliminates all middlemen: files go directly from device to device. There are no storage limits beyond your own disk space, no subscription fees, and no data leaves your network. Setup takes minutes and runs continuously in the background.

How to use

1. Install Syncthing:

# Linux
curl -s https://syncthing.net/release-key.gpg | sudo tee /etc/apt/trusted.gpg.d/syncthing.asc
sudo apt install syncthing

# macOS
brew install syncthing

# Or download from https://syncthing.net/downloads/

1. Start Syncthing and open the web UI:

syncthing
# Open http://localhost:8384

1. Add a remote device by exchanging device IDs, then share a folder between devices.

Example

Syncing a project directory between a laptop and desktop:

# On both machines, start Syncthing
syncthing

# On Machine A: note the Device ID from the web UI
# On Machine B: Add Remote Device -> paste Machine A's ID
# On Machine A: Accept the device pairing request

# On Machine A: Add Folder -> select ~/projects/myapp
# Share with Machine B
# Machine B accepts the folder share

# Files now sync continuously between both machines
# Changes on either side propagate automatically

Related on TokRepo

• Self-hosted tools — Browse self-hosted file and sync tools
• Security tools — Explore privacy and encryption tools

Common pitfalls

• Not setting up ignore patterns for build artifacts and node_modules. Syncthing will sync everything in shared folders. Create a .stignore file to exclude large, regeneratable directories.
• Expecting Syncthing to work like a backup tool. Syncthing is synchronization, not backup. If you delete a file on one device, it is deleted on all synced devices. Use Syncthing's file versioning feature for undo capability.
• Running Syncthing without a firewall exception. Syncthing needs ports 22000 (TCP/QUIC) for data transfer and 21027 (UDP) for discovery. Without these, sync relies on relay servers, which is slower.