expose

Zero-dependency tunnel — expose localhost to *.site.com using only Node's built-in net module.

http://localhost:3000  →  https://abc1f3.site.com

Install & run (client)

# Run directly with npx (no install needed)
npx expose 3000

# Or install globally
npm install -g expose
expose 3000

# With a custom subdomain
expose 3000 myapp
# → https://myapp.site.com

Environment variables

| Variable | Default | Description | |-----------------|------------------|------------------------------| | EXPOSE_SERVER | tunnel.site.com| Tunnel server hostname | | EXPOSE_PORT | 2000 | Tunnel server TCP port |

Deploy the server on site.com

node server.js --http-port 80 --tunnel-port 2000 --domain site.com

Flags / env vars

| Flag | Env var | Default | |------------------|---------------|-------------| | --http-port | HTTP_PORT | 80 | | --tunnel-port | TUNNEL_PORT | 2000 | | --domain | DOMAIN | site.com |

Keep alive with PM2

npm i -g pm2
pm2 start server.js --name expose-server -- --http-port 80 --domain site.com
pm2 save && pm2 startup

nginx + TLS (recommended)

Issue a wildcard cert first:

certbot certonly --manual --preferred-challenges dns -d "*.site.com" -d "site.com"

Then add a site config:

server {
    listen 443 ssl;
    server_name *.site.com;

    ssl_certificate     /etc/letsencrypt/live/site.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/site.com/privkey.pem;

    location / {
        proxy_pass         http://127.0.0.1:80;
        proxy_set_header   Host $host;
        proxy_set_header   X-Real-IP $remote_addr;
    }
}

How it works

Browser
  │  HTTPS → nginx → port 80
  ▼
server.js  (http.Server — public)
  │  JSON line over TCP socket (port 2000)
  ▼
expose.js  (net.createConnection — your machine)
  │  http.request
  ▼
localhost:3000

1. Client opens a raw TCP socket to site.com:2000 and sends a register message.
2. Server assigns a subdomain and replies ready with the public URL.
3. Browser hits https://abc1f3.site.com → nginx → server's HTTP listener.
4. Server sends a request JSON line over the TCP socket.
5. Client forwards it to localhost:PORT, gets the response, sends response back.
6. Server writes the response to the waiting browser connection.

Zero dependencies. No WebSocket. No npm installs. Pure Node.