Syncthing P2P Sync

beginner

Syncthing for peer-to-peer file synchronization.

Overview

Syncthing is an open-source continuous file synchronization program that enables real-time, peer-to-peer file sharing between devices without relying on cloud services or centralized servers. Originally developed in 2013 as a privacy-focused alternative to commercial sync solutions, Syncthing uses end-to-end encryption and operates entirely on your own infrastructure, giving you complete control over your data while maintaining automatic synchronization across multiple devices. This Docker stack combines Syncthing with NGINX to create a robust file synchronization platform where Syncthing handles the peer-to-peer sync operations and device communication while NGINX provides HTTP acceleration and can serve as a reverse proxy for the web interface. The combination addresses common deployment challenges like port management, SSL termination, and scaling across multiple Syncthing instances in larger environments. This setup is ideal for privacy-conscious users, small teams, and organizations that need reliable file synchronization without monthly cloud storage fees or data sovereignty concerns. Home lab enthusiasts will appreciate the self-hosted nature, while small businesses benefit from unlimited storage capacity and no per-user licensing costs compared to commercial alternatives like Dropbox or Google Drive.

Key Features

Peer-to-peer synchronization with no central server or cloud dependency
End-to-end AES encryption with TLS 1.3 for data in transit
Real-time conflict detection and resolution with versioning support
Selective folder sharing with granular device permissions
Cross-platform device discovery via local broadcast and global discovery
Web-based GUI for device management and folder configuration
Bandwidth limiting and scheduling for sync operations
NGINX reverse proxy support for SSL termination and caching

Common Use Cases

1Personal file synchronization between home computers, laptops, and mobile devices
2Small team document sharing without cloud storage subscriptions
3Photographer workflow for syncing RAW files between editing workstations
4Developer environment synchronization across multiple development machines
5Remote office backup strategy with automatic file replication
6Home media server synchronization for music and video libraries
7Secure document sharing for legal or healthcare practices requiring HIPAA compliance

Prerequisites

Minimum 256MB RAM for Syncthing operations and file monitoring
Available ports 8384 (web UI), 22000 (sync), and 21027 (discovery)
Persistent storage location for synchronized files (minimum 1GB recommended)
Network connectivity between devices for peer-to-peer communication
Basic understanding of device IDs and folder sharing concepts
Firewall configuration allowing Syncthing discovery and sync ports

For development & testing. Review security settings, change default credentials, and test thoroughly before production use. See Terms

docker-compose.yml

1services: 
2  syncthing: 
3    image: syncthing/syncthing:latest
4    container_name: syncthing
5    restart: unless-stopped
6    hostname: syncthing
7    ports: 
8      - "${SYNCTHING_PORT:-8384}:8384"
9      - "22000:22000/tcp"
10      - "22000:22000/udp"
11      - "21027:21027/udp"
12    environment: 
13      - PUID=1000
14      - PGID=1000
15    volumes: 
16      - syncthing_config:/var/syncthing/config
17      - ${SYNC_PATH:-./sync}:/var/syncthing/data
18
19  nginx: 
20    image: nginx:alpine
21    container_name: syncthing-nginx
22    restart: unless-stopped
23    ports: 
24      - "${NGINX_PORT:-80}:80"
25    volumes: 
26      - ./nginx.conf:/etc/nginx/nginx.conf:ro
27
28volumes: 
29  syncthing_config:

.env Template

.env

1# Syncthing
2SYNCTHING_PORT=8384
3SYNC_PATH=./sync
4NGINX_PORT=80

Usage Notes

1Syncthing at http://localhost:8384
2Get device ID for pairing
3No cloud required
4End-to-end encrypted

Individual Services(2 services)

Copy individual services to mix and match with your existing compose files.

syncthing

syncthing:
  image: syncthing/syncthing:latest
  container_name: syncthing
  restart: unless-stopped
  hostname: syncthing
  ports:
    - ${SYNCTHING_PORT:-8384}:8384
    - 22000:22000/tcp
    - 22000:22000/udp
    - 21027:21027/udp
  environment:
    - PUID=1000
    - PGID=1000
  volumes:
    - syncthing_config:/var/syncthing/config
    - ${SYNC_PATH:-./sync}:/var/syncthing/data

nginx

nginx:
  image: nginx:alpine
  container_name: syncthing-nginx
  restart: unless-stopped
  ports:
    - ${NGINX_PORT:-80}:80
  volumes:
    - ./nginx.conf:/etc/nginx/nginx.conf:ro

Quick Start

terminal

1# 1. Create the compose file
2cat > docker-compose.yml << 'EOF'
3services:
4  syncthing:
5    image: syncthing/syncthing:latest
6    container_name: syncthing
7    restart: unless-stopped
8    hostname: syncthing
9    ports:
10      - "${SYNCTHING_PORT:-8384}:8384"
11      - "22000:22000/tcp"
12      - "22000:22000/udp"
13      - "21027:21027/udp"
14    environment:
15      - PUID=1000
16      - PGID=1000
17    volumes:
18      - syncthing_config:/var/syncthing/config
19      - ${SYNC_PATH:-./sync}:/var/syncthing/data
20
21  nginx:
22    image: nginx:alpine
23    container_name: syncthing-nginx
24    restart: unless-stopped
25    ports:
26      - "${NGINX_PORT:-80}:80"
27    volumes:
28      - ./nginx.conf:/etc/nginx/nginx.conf:ro
29
30volumes:
31  syncthing_config:
32EOF
33
34# 2. Create the .env file
35cat > .env << 'EOF'
36# Syncthing
37SYNCTHING_PORT=8384
38SYNC_PATH=./sync
39NGINX_PORT=80
40EOF
41
42# 3. Start the services
43docker compose up -d
44
45# 4. View logs
46docker compose logs -f

One-Liner

Run this command to download and set up the recipe in one step:

terminal

1curl -fsSL https://docker.recipes/api/recipes/syncthing-sync-stack/run | bash

Troubleshooting

Devices not discovering each other: Check firewall rules for ports 21027/udp and 22000, or manually add device IDs
Sync conflicts appearing frequently: Enable file versioning in folder settings and check for clock synchronization between devices
High CPU usage during initial sync: Adjust scan intervals in advanced folder settings and enable bandwidth limiting
Web UI showing 'CSRF Error': Clear browser cache and cookies, or access via localhost instead of external IP
Files not syncing after changes: Verify folder is not paused, check ignore patterns, and ensure sufficient disk space on target devices
NGINX proxy returning 502 errors: Confirm Syncthing container is healthy and listening on port 8384 before NGINX starts

Community Notes

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Download Recipe Kit

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Includes docker-compose.yml, .env template, README, and license

Components

syncthingnginx

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