Syncthing Sync: Horcruxes for your data

Time for a tech tip! If you want to make sure you have common files across devices (except iOS), a free solution is to use Syncthing .

Syncthing basically gives you digital horcruxes for your files. Your folders are replicated across devices you own, and it’ll stay synced as long as they’re connected to the internet and at your command and wherever physically possible.

What’s that supposed to mean?#

Syncthing gives you a potentially1 more powerful alternative to cloud storage. Instead of relying on a cloud storage provider for their services, you host it yourself on devices you already own, and its resilience is as powerful as the number of devices connected to each other, whether it’s on the same network (local network discovery, yay!) or the internet.

That doesn’t mean cloud storage is bad2 by the way, since your data is stored on their production-grade servers that are maintained by professionals and technical experts. But cloud storage costs a lot of money once you go beyond the free capacity, and well, they have your data. That’s not necessarily bad, but that also means your data is under the mercy of their terms of service, the mercy of whatever laws and geographical restrictions it’s in (not that you should ever have questionable data to begin with, mind you.) and anything that happens in between your devices and connecting to them.

How would you use Syncthing?#

You can use it for nearly anything, to be honest, but there are some pointers when to use and when not to use it.

  • It’s good for documents, as long as no one’s editing the same file in multiple devices at the same time. 3

  • It’ll work for large files too, but be careful about data charges and your use cases. If it’s all gonna run internally at home, it’s fine. But if you have your phone or a server somewhere out there to sync, this might pose a problem since it takes time to sync and data charges if you’re not on unlimited data.

  • It’s not advisable for hot files that are used simultaneously by multiple clients. An example of this are game files; it’s not a problem if you’re running a game and syncing its saves, but if multiple people are running the same game across multiple devices, it’ll be problematic to sync. Conflicts ahoy.3

  • Be extra careful when using Syncthing for sensitive data. Syncthing itself is secure and private, but that means if any of your devices gets compromised somehow, the effects will also propagate across your synced devices as well. Just keep this in mind since that means your most insecure device is the easiest way for bad actors to get to your data.4


  1. I say potentially because it really depends on what you have, and your ability to maintain your data can be both a good and a bad thing. ↩︎

  2. If I have to cite reasons why the cloud is better and not Syncthing, data security. Syncthing is secure and powerful, but if any of your synced devices have weak points, you may end up syncing bad data (ex: corrupted, or worse, cryptolocked data) between your sync targets. Not that the cloud is immune to these kinds of threats, but at least you can possibly revert bad edits with their more robust version history, and for desperate times, you can turn to customer support. Oh and of course, connection speeds are another thing the cloud services are better at doing. ↩︎

  3. Conflicts are an issue for anything, really. Cloud storage providers have this issue too. Although this isn’t much of a big deal as long as you keep in mind that you won’t edit the same file across multiple devices at the same time, and making sure your sync status is up-to-date before making edits elsewhere. ↩︎

  4. This is a normal expectation for shared files in general. Backups and sync means that your files are always kept secure in case a device fails, but it does expand your attack surface since a bad actor has many avenues to get to your data too. This shouldn’t be a problem if you’re able to keep your devices secure, but yeah, vulnerablilties and software bugs are always out there. ↩︎

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