explaingit

syncthing/syncthing

🔥 Hot★ 84,160GoAudience · vibe coderComplexity · 2/5ActiveLicenseSetup · moderate

TLDR

Peer-to-peer file synchronization that keeps folders in sync across your devices automatically, without uploading to a cloud service.

Mindmap

mindmap
  root((Syncthing))
    What it does
      Syncs folders across devices
      Peer-to-peer, no cloud
      Automatic background sync
    Key features
      Data never lost
      Encrypted transfers
      Auto-upgrade with signatures
    Supported platforms
      Windows, Mac, Linux
      Docker container
      Mobile interfaces
    Use cases
      Personal device sync
      Family backups
      Folder mirroring
    Tech stack
      Go language
      ECDSA cryptography
      GPG signing

Things people build with this

USE CASE 1

Sync files between your laptop, desktop, and phone without uploading to Dropbox or iCloud.

USE CASE 2

Keep family photo backups automatically replicated across multiple computers you control.

USE CASE 3

Mirror a folder across several machines in your home network without a central server.

Tech stack

GoECDSAGPGDocker

Getting it running

Difficulty · moderate Time to first run · 30min

Requires Docker to run and understanding of peer discovery/network configuration for multi-device sync.

Use freely for any purpose, including commercial use, as long as you include the license notice and disclose source code modifications.

In plain English

Syncthing is a continuous file synchronization program. In plain terms, it keeps a folder on one computer in sync with the same folder on one or more other computers, automatically and in the background. If you add a file on your laptop, it appears on your desktop a moment later; if you edit a document on your phone, the new version shows up everywhere else you have linked. The repository describes itself as peer-to-peer, meaning the computers talk directly to each other instead of uploading everything to a central cloud service first. The goals listed in the README, in priority order, are: never lose user data, never allow eavesdropping or unauthorized modification, be easy to use, work automatically without bothering the user, run on every common computer, and stay focused on individual users rather than enterprise needs. To achieve those goals, releases are GPG-signed, and there is a built-in automatic-upgrade mechanism that verifies updates with a compiled-in ECDSA cryptographic signature. The macOS and Windows binaries are also code-signed. Several community-built graphical interfaces exist for Windows, Mac, and Linux, and a Docker setup is provided for running it in a container. The project is written in Go and licensed under the Mozilla Public License version 2. Use Syncthing when you want files automatically replicated between your own devices without trusting a third-party cloud service such as Dropbox or iCloud, when you want to keep family backups across machines, or when you simply want one folder mirrored across several computers you control.

Copy-paste prompts

Prompt 1
How do I set up Syncthing to sync a folder between my Windows laptop and Mac desktop?
Prompt 2
Show me how to add a new device to Syncthing and start syncing a folder with it.
Prompt 3
What are the security features in Syncthing that prevent eavesdropping on my synced files?
Prompt 4
How do I install and run Syncthing in Docker on my home server?
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Generated 2026-05-18 · Model: sonnet-4-6 · Verify against the repo before relying on details.