Sync Files Between Any Two Computers — No Cloud Needed

// Before you start

What you need

Two computers (Windows, Mac, or Linux) on any network
Ability to download and run a program
A folder you want to keep in sync
Both computers powered on when syncing

Step 1 of 6

Download Syncthing on the first computer

3 min

Syncthing ships as a single pre-built file — no installer wizard, no dependencies. Go to the official download page and grab the right version for your operating system. On Windows grab the .exe zip, on Mac grab the darwin package, on Linux grab the linux-amd64 tar.gz. You do not need to build anything from source.

Terminal · mac

$ https://github.com/syncthing/syncthing/releases/latest

$ # Download the file for your OS from the Assets section.

$ # Windows example filename: syncthing-windows-amd64-v1.x.x.zip

$ # Mac example filename: syncthing-macos-amd64-v1.x.x.tar.gz

$ # Linux example filename: syncthing-linux-amd64-v1.x.x.tar.gz

What you should see

A zip or tar.gz archive lands in your Downloads folder.

This might happen

You see many files in the Assets list and are unsure which to pick.

Match your OS and chip: most modern Windows/Linux PCs use amd64. Apple Silicon Macs use arm64. Older Raspberry Pis use arm.

Step 2 of 6

Extract and launch Syncthing on the first computer

2 min

Unzip the archive you downloaded. Inside you will find a single executable called 'syncthing' (or 'syncthing.exe' on Windows). Double-click it, or run the command below. Syncthing will open a browser tab automatically showing its web dashboard on localhost:8384. Leave the terminal window open — closing it stops Syncthing.

Terminal · mac

$ # Windows (run in the folder where you unzipped):

$ syncthing.exe

$ # Mac / Linux (run in the folder where you extracted):

$ ./syncthing

What you should see

A browser tab opens at http://127.0.0.1:8384 showing the Syncthing dashboard. You may see a first-run wizard.

This might happen

Mac says the app cannot be opened because it is from an unidentified developer.

Right-click the syncthing file, choose Open, then click Open again in the dialog. You only need to do this once.

Step 3 of 6

Note your Device ID on the first computer

1 min

Every Syncthing installation has a unique Device ID — a long string of letters and numbers. You will need this to link your two computers together. Find it in the dashboard by clicking Actions (top right) then Show ID. Copy the full ID or the QR code — you will paste it on the second computer shortly.

Terminal · mac

$ # No command needed.

$ # In the browser dashboard: click Actions > Show ID

$ # Copy the Device ID string (looks like: XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX)

What you should see

A dialog shows your Device ID and a QR code.

Step 4 of 6

Install and launch Syncthing on the second computer

3 min

Repeat steps 1 and 2 exactly on your second computer. Download the correct package for that machine's OS, extract it, and run the executable. Its own dashboard will open at http://127.0.0.1:8384. Now add the first computer as a remote device: click Add Remote Device, paste the Device ID you copied in step 3, give it a friendly name, and click Save.

Terminal · mac

$ # Same as steps 1-2 on the second machine.

$ # Then in the dashboard:

$ # Click '+ Add Remote Device'

$ # Paste the Device ID from computer 1

$ # Give it a name (e.g. 'Home Desktop')

$ # Click Save

What you should see

The first computer's dashboard shows a notification asking you to confirm the new device. Click Add Device on computer 1 to accept.

This might happen

The confirmation popup never appears on computer 1.

Make sure both computers are on the same local network, or that neither has a firewall blocking port 22000. Check your router or Windows Firewall settings and allow Syncthing through.

Step 5 of 6

Share a folder between the two computers

2 min

Now tell Syncthing which folder to keep in sync. On computer 1, click Add Folder in the dashboard. Choose a folder path on your drive, give it a label, then under the Sharing tab tick the second computer's name. Click Save. Computer 2 will receive a prompt asking whether to accept the shared folder — click Add. Pick where on computer 2 you want the files to live, then click Save.

Terminal · mac

$ # No command needed — all done in the browser dashboard.

$ # Computer 1: click '+ Add Folder' > set path > Sharing tab > tick Computer 2 > Save

$ # Computer 2: accept the incoming folder share popup > choose local path > Save

What you should see

Both dashboards show the folder with a green 'Up to Date' status once the initial sync completes. Files placed in the folder on either machine will appear on the other.

This might happen

Status stays 'Syncing' for a long time on a large folder.

This is normal for the first sync of many files. Leave both machines running and connected. Progress is shown as a percentage in the dashboard.

Step 6 of 6

Keep Syncthing running automatically at startup (optional)

5 min

By default Syncthing only runs while you have the terminal open. To make it start automatically when your computer boots, follow the platform-specific instructions in the official docs. On Windows the simplest method is SyncTrayzor, a free wrapper that adds a system-tray icon and auto-start. On Mac you can use the provided launchd plist. On Linux use the provided systemd service file.

Terminal · mac

$ # Windows — download SyncTrayzor (a Syncthing wrapper with auto-start):

$ https://github.com/canton7/SyncTrayzor/releases/latest

$ # Linux systemd (run once per user):

$ systemctl --user enable syncthing

$ systemctl --user start syncthing

$ # Mac launchd plist is in the etc/macos-launchd folder inside the archive.

$ # Copy it to ~/Library/LaunchAgents/ and run:

$ launchctl load ~/Library/LaunchAgents/net.syncthing.syncthing.plist

What you should see

Syncthing starts automatically on login. The dashboard is still reachable at http://127.0.0.1:8384.

This might happen

On Linux the systemctl command says 'Failed to connect to bus'.

Make sure you are logged in as your normal user (not root) and that systemd user sessions are enabled on your distro.

// Status

cooked. baked. worked.

Two (or more) computers with a chosen folder kept automatically in sync, peer-to-peer, with no cloud account or subscription required.

// the honest bit

The honest part

Syncthing syncs only while both devices are online at the same time — it is not a backup service. If you delete a file on one machine it will be deleted on the other (though versioning can be enabled in folder settings). It works best on a local network; syncing over the internet is possible via relay servers but can be slower. There is no mobile-friendly web UI built in, though third-party Android and iOS apps exist.