This free tool keeps my files synced everywhere without the cloud

Keeping your data synced across multiple devices is one of the biggest challenges of using multiple devices. Sure, you can upload your data to cloud storage services so it's accessible from any of your devices. But this convenience comes at the risk of privacy.

Similarly, you could create your own cloud storage using Nextcloud to keep your data accessible across all your devices while retaining complete control of it. However, it takes time and effort, and you need dedicated hardware to self-host Nextcloud. Additionally, it may be overkill if you want to keep just a handful of files synced.

This is where Syncthing comes into play. I've been using Syncthing for a while to keep files synced across some of my devices without the cloud, and I'm loving it.

What is Syncthing, and how does it work?

Understanding Syncthing's peer-to-peer syncing

Syncthing is a peer-to-peer file syncing app that allows you to sync files across multiple devices without relying on a central server or third-party cloud service. You can use it for syncing documents, photos, videos, and other types of data. All the transfers happen over an encrypted channel, ensuring privacy and security.

Syncthing works by scanning all the files in a folder and breaking them into small blocks. Then, whenever there's a change in a file, it only sends the modified blocks to other devices, saving both time and data. If a file is changed on multiple devices simultaneously, Syncthing retains both versions and renames the conflicting file to prevent data loss.

For Syncthing to sync files, the devices must be powered on, and the app must be running. If a device is turned off or disconnected, Syncthing pauses syncing on that device; changes are continuously tracked on other devices. When the device turns back on and Syncthing starts again, all queued changes are synced automatically.

Why I use Syncthing over other services

Key features that make it stand out

I've long relied on Google Drive and Dropbox to keep my important documents and other essential files accessible across all my devices. That is, until I turned my broken laptop into a home server and went on a spree to explore various self-hosted apps.

One of these apps was Nexcloud, a service that allows you to set up your own cloud storage, giving you complete control over your data. I quickly moved all my data to Nextcloud and set up my family's and my own devices to access it. However, I soon realized that Nextcloud isn't ideal when I want to keep just a few files synced across devices.

That's when I decided to give peer-to-peer file syncing apps a shot. Of the few I tried, Syncthing stood out to me because it's open source and offers all the essential features I need—conflict detection and handling, version control, and the ability to sync folders independently across devices—for free. I quickly moved my frequently needed files to it. Unlike Nextcloud, Syncthing offers straightforward and fast peer-to-peer file syncing, making it ideal for my use case.

Thanks to it, I can also sync a bunch of work and personal project folders between my Mac and Windows/Linux laptop and access them regardless of the device I'm using. This saves me the hassle of constantly sending files between devices using file-sharing apps like LocalSend or accessing/downloading them from my Nextcloud server.

Setting up and using Syncthing

Set up once, sync effortlessly forever

Setting up your own sync system with Syncthing involves multiple steps. You can get Syncthing running between multiple computers, multiple phones, or a mix of both, as required.

Installation and basic setup

Start by downloading and installing the Syncthing app on the devices on which you want to keep your files synced. Syncthing is available on all major desktop platforms, including Linux, macOS, and Windows. Unfortunately, there's no official Syncthing app for Android and iPhone, so you'll need to use their forks or third-party apps. Syncthing-Fork and Synctrain are popular options for Android and iPhone, respectively.

Open the Syncthing app on your computer. It'll generate the required configuration files and a unique device ID, and also start a local web server. You can access it on your computer by heading to http://localhost:8284 in a web browser.

Here, you'll be prompted to set up a username and password to prevent unauthorized access to the Syncthing web interface.

1. Hit Settings to open the GUI settings. Alternatively, click Actions, choose Settings, and go to the GUI tab.
2. Type a username and password in the GUI Authentication User and GUI Authentication Password fields, respectively, and hit Save.
   • You can also enable the Use HTTPS for GUI option for improved security.

3. Additionally, you can set a memorable name for the device to make managing and monitoring devices easier. Go to Syncthing settings in the web interface. On the General tab, click on the Device Name text field and type your preferred name.
4. Hit Save to save the change.

Finally, you must add Syncthing to your computer's startup programs list. This way, Syncthing will be automatically up and running as soon as your computer boots, so you don't need to launch it manually. Adding an app to your Mac's startup list is easy. On Windows and Linux PCs, you can look up the steps for your operating system.

Adding devices

With the basic setup complete, the next step is to link the devices you want to sync files between. To do this on a desktop:

1. Access the Syncthing web GUI, click Actions in the top-right corner, and select Show ID. If you're on a mobile device, tap the three-dot menu in the top-left corner and choose Show device ID.
2. Then, on another device, click Add Remote Device in the bottom-right corner of the page, type the device ID for the first device, and hit Save. If you're on a phone, go to the Devices tab, tap the new device icon (with the + button) in the top-right corner, and populate the fields.

You can also type the device name in the Device Name field to show it in place of the device ID in the cluster status. Alternatively, you can show the QR code on one device and scan it using the other to establish a connection.

After you do this, you'll see a notification on the first device, prompting you about the connection request. Tap the check mark to accept and connect to the second device. You'll see the Connected status next to the linked device on both the web interface and the mobile app.

Adding folders to sync

After you've linked the devices, it's time to add the folders you want to sync.

1. Head to the Syncthing web GUI and hit the Add Folder button. Here, give a descriptive label for the folder in the Folder Label text field.
2. Then, type the path to the folder on your computer that you want to sync. You may see a prompt requesting access to the folder. Grant it permission.
3. Switch to the Sharing tab. Under Unshared Devices, tick the checkbox next to the device you just added and hit Save. You'll see a notification on the other devices, asking if you want to add the shared folder.
4. Hit Add to proceed.

You'll now need to add a label and enter the path to the folder where you want the synced files stored. Finally, hit Save.

Syncing files

Now that you've configured everything, whenever you create, modify, or delete files or subfolders inside the synced folder on any of your synced devices, the changes are synced across all of them. This happens automatically and in real-time, without any intervention.

Setting up file versioning

By default, Syncthing doesn't use file versioning, meaning it doesn't store old versions when files are deleted or replaced from other devices. However, if you're using Syncthing to sync files that change frequently, it's best to set up file versioning to avoid losing data due to accidental changes.

Syncthing offers multiple file versioning options. Its web GUI has a Help button that takes you to a blog explaining each option and its use case in detail. But generally speaking, the staggered file versioning system is considered the best option for most people. It strikes the right balance between retaining useful version history and managing storage space by keeping multiple versions spaced out over time—more new versions and fewer old versions—and automatically pruning old versions.

To do this, click the folder in sync and hit Edit. Go to the File Versioning tab, click the drop-down, and select an appropriate option. Hit Save.

Syncthing isn't the only peer-to-peer file syncing tool

Other tools use the same concept, too

There are many Syncthing alternatives available that also provide peer-to-peer, decentralized file syncing. Popular options include Resilio Sync, Librevault, and Rclone, with Resilio Sync being the most widely preferred due to its performance and ease of use. Choosing the right tool boils down to your syncing needs, platforms you use, and other feature requirements.