Syncthing on a Seedbox: Decentralised File Sync

What Syncthing Is

Syncthing is peer-to-peer file sync. There's no cloud account, no server in the middle. Each device runs Syncthing, you tell two devices about each other, and they sync the folders you've configured between them.

Think Dropbox without Dropbox. Or BitTorrent Sync without the BitTorrent Sync company.

Why Run It on a Seedbox?

A seedbox makes a great always-on Syncthing peer:

• It's online 24/7, so phones and laptops can sync to it whenever they're connected
• 10 Gbit upload speeds large folder syncs up dramatically
• One-click install
• Acts as the relay node when your devices aren't online at the same time
• EU servers in Luxembourg, France, and Netherlands

Common Use Cases

Three patterns most people land on:

1. Photo backup. Phone uploads to a Syncthing folder; the seedbox keeps a perpetual copy.
2. Cross-device working folder. Laptop and desktop share a folder; whatever you save on one is on the other.
3. Backup of media folders. Your seedbox already has the library; replicate it to a home NAS via Syncthing for offsite redundancy.

Installing Syncthing

Open the Bytesized Panel, find Syncthing in the app catalog, click install. The panel handles the binary, the web UI, the reverse proxy.

Click "Open" to land on the web UI.

First-Run Setup

Syncthing's first-run UI is sparse. Three things to do:

1. Set the GUI password. Actions > Settings > GUI > Authentication. Important; the slice's GUI is reachable via your panel and you don't want anyone guessing.
2. Note your device ID. Top-right corner of the dashboard. You'll paste this into other devices to introduce them.
3. Add a folder. Folders are the unit of sync. Pick a folder under your home directory and give it a label.

Adding a Second Device

On your phone or laptop, install Syncthing and open it. Get the device ID from the new device.

Back on the seedbox Syncthing:

• Click "Add Remote Device"
• Paste the new device's ID
• Approve the device

The device approves the seedbox in turn. Now you can share folders between them: edit a folder on the seedbox, click the new device, and share it.

Folder Defaults

Syncthing has three sync modes per folder:

• Send & Receive. Both sides update each other. Default for working folders.
• Send Only. This device pushes; doesn't accept incoming. Useful for the seedbox if you want it as the canonical copy.
• Receive Only. This device only accepts incoming. Useful for backup-only mirrors.

Pick per folder. A photo backup is usually Receive Only on the seedbox (phone pushes, seedbox accepts, no overwrites).

Common Gotchas

Devices not connecting. Most often firewall on the device side. Syncthing uses port 22000 by default; the seedbox is open by virtue of the panel setup. The home device may need port forwarding for direct connections (Syncthing falls back to relay servers if needed).

Sync speed slow. Syncthing prefers direct device-to-device. If both devices are NATed and can't reach each other, traffic goes through public relay servers, which are slow. Open port 22000 on at least one side for direct sync.

Conflicts piling up. Syncthing creates .sync-conflict-* files when both sides edit at once. Clean them up; usually means a clock skew or both devices saving the same file independently.

Storage full. Syncthing can sync everything by default. Set folder ignore rules (.stignore file in the folder) to skip caches, temp files, build artefacts.

FAQ

Is Syncthing free? Yes. Free and open source.

Does it use the cloud? No. Files go directly between your devices. The discovery and relay servers (run by the Syncthing project, free) help devices find each other; they don't see your file contents.

Will it replace Dropbox? For sync, yes. For collaborative editing (Google Docs-style real-time), no.

Is it encrypted in transit? Yes. TLS between devices.

Will it work on iOS? The official Syncthing project doesn't have iOS support. There are unofficial alternatives; on iOS most people use Nextcloud for files and Syncthing on Android/desktop only.

Ready to Set It Up?

Browse Appbox plans, install Syncthing from the panel, get devices talking.