Syncthing Review – Free & Open Source File Synchronization Service

Quick Overview on Syncthing

Syncthing is relatively a new service in the file synchronizing and sharing industry. Competing against the likes of BitTorrent Sync, it provides a fresh take on sharing files between two or more devices. Syncthing is a free service that you can use on multiple platforms. In our Syncthing review, we put the software to the test. We investigated how the service works, what security features it adopts, and how does it compare to other file sharing service. Carry on reading all the details!


  • No third party cloud storage involved
  • It is free to use (FOSS)
  • Open source
  • Compatible on Windows, Linux, Mac OS, and Android
  • Offers File Versioning feature
  • Documented protocols
  • Stronger ciphers can be configured


  • Complicated setup process
  • No app for iOS (but it is in beta testing phase)

What is Syncthing?

Syncthing is free and open source file synchronization application. In a market where there are many file synchronization service, Syncthing provides superior security measures. You can use it to share files between different devices connected to a local network or the internet.

One of the primary advantages of using Syncthing is that there are no third-party cloud storage services. You control the destination where your data is stored and backed up. When using Syncthing, you can assign a computer, server, or any other hardware to store your data. This is what is known as BYO cloud model, where you provide the hardware and the software runs on it.

Prices and Packages of Syncthing

As we mentioned earlier, Syncthing is free and open source software (FOSS). You do not have to pay or subscribe to Syncthing to use it compatible platforms. However, Syncthing is crowd-sourced and accepts donations in the form of Bitcoin or through credit card payments. If you want to use a VPN without paying so check this out 5 Best Free VPN.

Compatibility of Syncthing

Our Syncthing review revealed that the software is compatible with popular operating systems such as Windows, Mac OS X, Android, and Linux. You can also use Syncthing on FreeBSD, Solaris, Dragonfly BSD, NetBSD, and OpenBSD. Just download the service directly from Syncthing’s official website and you’ll be ready to sync files from one device to another.

For Android users, download the app from Google Play Store. On the contrary, Syncthing also offers its app on F-Droid for users who don’t prefer using the Play Store.

Sadly, the service is not yet compatible with iOS devices. According to Syncthing’s forum, beta testing is underway for an iOS app. You can download the beta version of Syncthing on your iOS device, but it has limited features such as partial synchronization. Syncthing has not yet confirm an exact release date for an iOS app; probably we will see an app after successful rounds of beta testing.

Syncthing Staggered File Versioning

Syncthing offers the feature of File Versioning. What it does that it archives an older version of the file if the software is deleted or updated. We found this feature quite interesting in our Syncthing review as you can access the older version at a later point.

There are different ways Syncthing uses file versioning. Some of these include staggered file versioning, simple file versioning, or trash can approach. Do note that the default setting of Syncthing is ‘no file versioning’, but it allows you to choose how many versions should be stored.

Syncthing Security and Privacy Features

For our Syncthing review, we explored the security and privacy features offered by the service. The open source nature of Syncthing makes it a secure software to use. We can be sure that there are no backdoors built into the service. Likewise, Syncthing does not use any third party cloud storage services to store your data; rather you decide where you want to back up the data. This makes it a safe service to transfer files between multiple devices.

Besides these aspects, Syncthing utilizes different protocols as security and privacy features to safeguard your data while transferring. Here’s a look at the different protocols used by Syncthing:

Syncthing Block Exchange Protocol v1

Syncthing uses Block Exchange Protocol v1 to exchange metadata and files between two or more devices. The Block Exchange Protocol v1 breaks down the file into smaller units and transfers them in blocks. It uses TLS 1.2 or higher revisions for encryption and authentication, along with Perfect Forward Secrecy (PFS). Syncthing also lets you chose stronger cipher suits for better security and provided such examples:

Global Discovery v3

Syncthing uses Global Discovery v3 protocol to find devices over the internet.

Local Discovery Protocol v4

Now if you device is located on LAN or a locally broadcasted domain, Syncthing uses Local Discovery protocol v4 to identify devices.

Relay Protocol v1

Syncthing uses Relay Protocol v1 to relay data between two devices, which cannot connect with each other directly.

Syncthing Setup Process

Now for the tricky bit for our Syncthing review – the setup process. Since Syncthing doesn’t require any subscription, just download the software or app onto your device and start using it. For complete security and anonymity, it is better to use Syncthing on Linux. However, it can be configured across multiple platforms.

For our demonstration, we will be synchronizing files from our Windows PC with an Android device. When you download the software on Windows, just unzip the downloaded files and run the program, you won’t require any elaborate installation. Once the software launches, you will see the following interface on your web browser:

Next, you will have to add a device with which you want to sync your data. In this case, we used our Android phone. Once you have downloaded and installed Syncthing app on Android, you will have to share the Device ID with both the devices so that they can communicate with each other

This can be done by emailing the device ID of your PC to your device and entering the ID. Another method is by scanning the QR code of your Windows PC on your Android device. When we scanned the QR code, a notification appeared on our PC, showing our Android phone’s Device ID.

When you have added the device ID for both the devices, restart Syncthing on each device. This was an annoying part while reviewing Syncthing, as you have to restart the software after every step.

Now, the next step is to create a folder on one of the devices. If the folder is already created, simply share it with the device for synchronization.

When you have created the folder, the files should now transfer to the corresponding folder on the other device. In this case, the files held on our Windows PC folder synced with the folder created on our Android phone. However, if you delete files from one folder, the files will also delete from the folder on your other device. You can turn on the ‘Folder Master’ feature, which will ignore any changes made to the folder.

Syncthing vs. BitTorrent Sync

For our Syncthing review, we compared the software to BiTorrent Sync. Syncthing offers similar features as BitTorrent Sync, however, there are subtle differences between the two. Both services are used for the same purpose, to share data among two or more devices. Here’s how Syncthing differs from BitTorrent Sync:

  • Syncthing is open source, while BitTorrent Sync is not open source
  • Syncthing has documented protocols, BitTorrent Sync doesn’t
  • BitTorrent offers app for iOS and Syncthing has its iOS app in beta testing phase

In an exception to these technical details, we used both the services for comparison. BitTorrent Sync has a better UI and sharing files between different devices is much easier. Syncthing has a complicated setup process, and while our demonstration looks easy, we ran into many difficulties while connecting our two devices.


To wrap things up, Syncthing is a lightweight file synchronization software. From our Syncthing review, it is clear that this FOSS application provides far better security and privacy as compared to other commercial software. The main reason for this is down to how Syncthing works.

Since you provide the hardware for data storage, there are no third parties involved, keeping your data safe and secure at all times. Its documented protocols and end-to-end encryption add another layer of security.

However, the setup process can be very tedious and complex. For not so tech savvy users, synchronizing multiple devices can be a nightmare. We found it difficult connecting two of our devices. Syncthing should look into this issue and try to make the process simpler and easier for all users. Nevertheless, when you finally get to sync your devices, there is no better file synchronization service than Syncthing.

Related Articles

Aazim Akhtar

Aazim Akhtar

Senior Editor
All Posts by Aazim Akhtar

Aazim Akhtar's Biography :

A privacy advocate by day and a binge-watcher by night, Aazim Akhtar loves to write about online security, internet freedom, and all the latest technological trends. Finding ways to secure any sensitive data and protect against existing and emerging cyber threats is his passion. Follow him on Twitter to stay in touch with his work!

Leave a Reply

Your email address will not be published. Required fields are marked *

By submitting this form you agree to our Terms of service and Privacy Policy