nginx.conf

events {
    worker_connections 1024;
}

http {
    include mime.types;
    default_type application/octet-stream;

    upstream backend {
        server server:5000;
        # Enable sticky sessions if using multiple socket.io nodes
        # ip_hash; 
    }

    server {
        listen 80;
        server_name _;

        # Serve static frontend files
        location / {
            root /usr/share/nginx/html;
            index index.html;
            try_files $uri $uri/ /index.html;
        }

        # Proxy Socket.IO connections
        location /socket.io/ {
            proxy_pass http://backend;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

        # Proxy standard API requests
        location /api/ {
            proxy_pass http://backend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
        }
    }
}