Try setting SINGLE_ROOM to 1 if you cannot see other peers, note that this would make everyone able to see each other regardless of their connection method.

Environment variables:

Environment	Default value	Description
HTTP_PORT	8080	Port of internal Lighttpd proxy, set to 0 to disable
PORT	3000	Port of Snapdrop WebSocket server
SINGLE_ROOM	0	Single room mode (all peers see each other on the same server regardless of network)
STUN_SERVER	stun:stun.l.google.com:19302	STUN server URL

Deploying

1. Docker

Terminal

docker run -d \
    --name snapdrop \
    -e HTTP_PORT=8080 \
    -e PORT=3000 \
    -e SINGLE_ROOM=0 \
    -e STUN_SERVER=stun:stun.l.google.com:19302 \
    -p 3000:3000 `# optional: only if not using Lighttpd proxy in container` \
    -p 8080:8080 \
    -v /var/www/snapdrop:/home/node/client `# optional: only if not using Lighttpd proxy in container` \
    --restart unless-stopped \
    jarylc/snapdrop

Docker-compose

snapdrop:
    image: jarylc/snapdrop
    ports:
        - "3000:3000" # optional: only if not using Lighttpd proxy in container
        - "8080:8080"
    volumes: # optional: only if not using Lighttpd proxy in container
        - /var/www/snapdrop:/home/node/client
    environment:
        - HTTP_PORT=8080
        - PORT=3000
        - SINGLE_ROOM=0
        - STUN_SERVER=stun:stun.l.google.com:19302
    restart: unless-stopped

2a. Deployment through container Lighttpd only

Just assign the container's Lighttpd port (HTTP_PORT) to the designated port on the host you will access Snapdrop with.

2b. Deployment through container Lighttpd and host Nginx

location / { # trailing slash is required if under a subpath
    proxy_pass http://127.0.0.1:8080/; # trailing slash is important if under a subpath
    proxy_connect_timeout 300;
    proxy_http_version 1.1;
    proxy_set_header Connection "upgrade";
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header X-Forwarded-for $remote_addr;
}

2c. Deployment only on host Nginx

Under /

location / {
    root /var/www/snapdrop;
    index index.html;
}

location /server {
    proxy_pass http://127.0.0.1:3000;
    proxy_connect_timeout 300;
    proxy_http_version 1.1;
    proxy_set_header Connection "upgrade";
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header X-Forwarded-for $remote_addr;
}

Under /snapdrop

location /snapdrop {
    alias /var/www/snapdrop;
    index index.html;
}

location /snapdrop/server {
    proxy_pass http://127.0.0.1:3000;
    proxy_connect_timeout 300;
    proxy_set_header Connection "upgrade";
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header X-Forwarded-for $remote_addr;
}