ScriptsApr 10, 2026·1 min read

Syncthing — Open Source Peer-to-Peer File Synchronization

Syncthing is a continuous file synchronization tool that syncs files between devices directly — no cloud, no servers, no accounts. Encrypted, private, and decentralized.

SC
Script Depot · Community
Quick Use

Use it first, then decide how deep to go

This block should tell both the user and the agent what to copy, install, and apply first.

# Linux/macOS
curl -s https://api.github.com/repos/syncthing/syncthing/releases/latest | 
  grep browser_download_url | grep linux-amd64 | head -1 | cut -d'"' -f4 | xargs curl -L -o syncthing.tar.gz
tar xzf syncthing.tar.gz && cd syncthing-*/
./syncthing

# Or Docker
docker run -d --name syncthing -p 8384:8384 -p 22000:22000/tcp -p 22000:22000/udp 
  -v syncthing-config:/var/syncthing/config -v /path/to/sync:/var/syncthing/data 
  syncthing/syncthing:latest

Open http://localhost:8384 — add devices and select folders to sync.

Intro

Syncthing is an open-source, peer-to-peer continuous file synchronization tool. Unlike Dropbox or Google Drive, Syncthing syncs files directly between your devices without routing through any cloud server — your data never leaves your network, and no third party has access to your files.

With 81.6K+ GitHub stars and MPL-2.0 license, Syncthing is one of the most popular open-source tools on GitHub, trusted by millions of users for private, secure file synchronization.

What Syncthing Does

  • Direct Sync: Files sync directly between devices — no cloud server intermediary
  • End-to-End Encryption: All communication encrypted with TLS 1.3
  • No Account Required: No signup, no login, no cloud subscription
  • Cross-Platform: Windows, macOS, Linux, Android, FreeBSD, Solaris
  • Selective Sync: Choose which folders to sync on each device
  • Versioning: File versioning with configurable retention (trash can, simple, staggered)
  • Ignore Patterns: .stignore files for excluding files/folders (like .gitignore)
  • Conflict Resolution: Automatic conflict detection with both versions preserved
  • NAT Traversal: Works through firewalls with relay fallback
  • Web UI: Beautiful management interface at localhost:8384

Architecture

┌──────────────┐           ┌──────────────┐
│  Device A    │◄─────────▶│  Device B    │
│  (Desktop)   │  Direct   │  (Laptop)    │
│  Syncthing   │  P2P      │  Syncthing   │
└──────┬───────┘           └──────────────┘
       │
       │ Direct P2P
       │
┌──────┴───────┐
│  Device C    │
│  (Phone)     │
│  Syncthing   │
└──────────────┘

No central server. All devices connect directly.
If direct connection fails → encrypted relay.

Self-Hosting

Docker Compose

services:
  syncthing:
    image: syncthing/syncthing:latest
    hostname: my-syncthing
    ports:
      - "8384:8384"    # Web UI
      - "22000:22000/tcp"  # Sync protocol
      - "22000:22000/udp"  # QUIC sync
      - "21027:21027/udp"  # Discovery
    volumes:
      - syncthing-config:/var/syncthing/config
      - /path/to/documents:/var/syncthing/Documents
      - /path/to/photos:/var/syncthing/Photos
    environment:
      PUID: 1000
      PGID: 1000
    restart: unless-stopped

volumes:
  syncthing-config:

Key Features

Folder Configuration

Folder Types:
├── Send & Receive — Full two-way sync (default)
├── Send Only — This device is the "master" copy
└── Receive Only — This device only receives updates

Versioning:
├── Trash Can — Deleted/replaced files moved to .stversions/
├── Simple — Keep N old versions
├── Staggered — Keep versions at increasing intervals
└── External — Run custom script on file changes

.stignore (Exclusion Patterns)

// .stignore file
(?d).DS_Store
(?d)Thumbs.db
(?d)desktop.ini
node_modules
.git
*.tmp
*.log
~*

Multi-Device Setup

Step 1: Install Syncthing on Device A
Step 2: Install Syncthing on Device B
Step 3: On Device A, click "Add Remote Device"
Step 4: Enter Device B's ID (shown in Device B's web UI)
Step 5: Accept connection on Device B
Step 6: Share folders between devices

Device IDs are automatically generated cryptographic identifiers — no passwords to share.

Use Cases

Scenario Setup
Laptop ↔ Desktop sync Send & Receive on both
Phone photo backup Send Only on phone, Receive Only on server
Team shared folder Send & Receive on all team devices
NAS backup Send Only from source, Receive Only on NAS
Dotfiles sync Sync ~/.config across Linux machines

Syncthing vs Alternatives

Feature Syncthing Dropbox Resilio Sync Nextcloud
Open Source Yes (MPL-2.0) No No Yes
P2P (no server) Yes No Yes No (server)
Cloud storage No Yes (cloud) No Self-hosted
Encryption E2E (TLS) At rest E2E At rest
Account needed No Yes Yes Yes
File versioning Yes 30-day Yes Yes
Mobile Android iOS+Android iOS+Android iOS+Android
iOS app Community (Möbius) Official Official Official

常见问题

Q: 没有中心服务器，设备怎么找到彼此？ A: Syncthing 使用全局发现服务器（仅用于交换 IP 地址，不传输文件）和本地网络发现（mDNS）。设备找到彼此后直接建立 P2P 连接。如果直连失败，会通过加密中继服务器转发。

Q: iOS 支持吗？ A: 官方没有 iOS 应用（Apple 对后台同步限制严格）。社区项目 Möbius Sync 提供 iOS 客户端。如果 iOS 同步是刚需，考虑 Nextcloud 或 Resilio。

Q: 能同步多大的文件/多少文件？ A: 没有限制。用户报告成功同步数百 GB 甚至 TB 级数据。数百万文件的同步也可以正常工作，但初始扫描可能需要较长时间。

来源与致谢

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