Portless

Portless

Replace port numbers with stable, named .localhost URLs. For humans and agents.

Why portless

• Port conflicts -- EADDRINUSE when two projects default to the same port
• Memorizing ports -- which app is on 3001 vs 8080?
• Refreshing shows the wrong app -- stop one server, start another on the same port, stale tab shows wrong content
• Monorepo multiplier -- every problem scales with each service in the repo
• Agents test the wrong port -- AI agents guess or hardcode the wrong port
• Cookie/storage clashes -- cookies on localhost bleed across apps; localStorage lost when ports shift
• Hardcoded ports in config -- CORS allowlists, OAuth redirects, .env files break when ports change
• Sharing URLs with teammates -- "what port is that on?" becomes a Slack question
• Browser history is useless -- localhost:3000 history is a mix of unrelated projects

Installation

portless is a global CLI tool. Do NOT add it as a project dependency (no npm install portless or pnpm add portless in a project). Do NOT use npx.

Install globally:

npm install -g portless

Quick Start

# Install globally
npm install -g portless

# Start the proxy (once, no sudo needed)
portless proxy start

# Run your app (auto-starts the proxy if needed)
portless myapp next dev
# -> http://myapp.localhost:1355

The proxy auto-starts when you run an app. You can also start it explicitly with portless proxy start.

Integration Patterns

package.json scripts

{
  "scripts": {
    "dev": "portless myapp next dev"
  }
}

The proxy auto-starts when you run an app. Or start it explicitly: portless proxy start.

Multi-app setups with subdomains

portless myapp next dev          # http://myapp.localhost:1355
portless api.myapp pnpm start    # http://api.myapp.localhost:1355
portless docs.myapp next dev     # http://docs.myapp.localhost:1355

Bypassing portless

Set PORTLESS=0 or PORTLESS=skip to run the command directly without the proxy:

PORTLESS=0 pnpm dev   # Bypasses proxy, uses default port

How It Works

1. portless proxy start starts an HTTP reverse proxy on port 1355 as a background daemon (configurable with -p / --port or the PORTLESS_PORT env var). The proxy also auto-starts when you run an app.
2. portless <name> <cmd> assigns a random free port (4000-4999) via the PORT env var and registers the app with the proxy
3. The browser hits http://<name>.localhost:1355 on the proxy port; the proxy forwards to the app's assigned port

.localhost domains resolve to 127.0.0.1 natively on macOS and Linux -- no /etc/hosts editing needed.

Most frameworks (Next.js, Vite, Express, etc.) respect the PORT env var automatically.

State directory

Portless stores its state (routes, PID file, port file) in a directory that depends on the proxy port:

• Port < 1024 (sudo required): /tmp/portless
• Port >= 1024 (no sudo): ~/.portless

Override with the PORTLESS_STATE_DIR environment variable.

Environment variables

CLI Reference

Troubleshooting

Proxy not running

The proxy auto-starts when you run an app with portless <name> <cmd>. If it doesn't start (e.g. port conflict), start it manually:

portless proxy start

Port already in use

Another process is bound to the proxy port. Either stop it first, or use a different port:

portless proxy start -p 8080

Framework not respecting PORT

Some frameworks need explicit configuration to use the PORT env var. Examples:

• Webpack Dev Server: use --port $PORT
• Custom servers: read process.env.PORT and listen on it

Permission errors

Ports below 1024 require sudo. The default port (1355) does not need sudo. If you want to use port 80:

sudo portless proxy start -p 80       # Port 80, requires sudo
portless proxy start                   # Port 1355, no sudo needed
portless proxy stop                    # Stop (use sudo if started with sudo)

Requirements

• Node.js 20+
• macOS or Linux