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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 or pnpm dlx.

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 run next dev
# -> http://<project>.localhost:1355

# Or with an explicit name
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 run 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

By default, only explicitly registered subdomains are routed (strict mode). Start the proxy with --wildcard to allow any subdomain of a registered route to fall back to that app (e.g. tenant1.myapp.localhost:1355 routes to the myapp app without extra registration). Exact matches always take priority over wildcards.

Git worktrees

portless run automatically detects git worktrees. In a linked worktree, the branch name is prepended as a subdomain prefix so each worktree gets a unique URL:

# Main worktree -- no prefix
portless run next dev   # -> http://myapp.localhost:1355

# Linked worktree on branch "fix-ui"
portless run next dev   # -> http://fix-ui.myapp.localhost:1355

No config changes needed. Put portless run in package.json once and it works in all worktrees.

Bypassing portless

Set PORTLESS=0 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 in Chrome, Firefox, and Edge. Safari relies on the system DNS resolver, which may not handle .localhost subdomains on all configurations. Run sudo portless hosts sync to add entries to /etc/hosts if needed.

Most frameworks (Next.js, Express, Nuxt, etc.) respect the PORT env var automatically. For frameworks that ignore PORT (Vite, Astro, React Router, Angular, Expo, React Native), portless auto-injects the correct --port and --host CLI flags.

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 (macOS/Linux only)
• Port >= 1024 (no sudo): ~/.portless
• Windows : Always ~/.portless (no privileged port concept)

Override with the PORTLESS_STATE_DIR environment variable.

Environment variables

HTTP/2 + HTTPS

Use --https for HTTP/2 multiplexing (faster page loads for dev servers with many files):

portless proxy start --https                  # Auto-generate certs and trust CA
portless proxy start --cert ./c.pem --key ./k.pem  # Use custom certs
sudo portless trust                           # Add CA to trust store later

First run generates a local CA and prompts for sudo to add it to the system trust store. After that, no prompts and no browser warnings. Set PORTLESS_HTTPS=1 in .bashrc/.zshrc to make it permanent.

On Linux, portless trust supports Debian/Ubuntu, Arch, Fedora/RHEL/CentOS, and openSUSE (via update-ca-certificates or update-ca-trust). On Windows, it uses certutil to add the CA to the system trust store.

CLI Reference

Reserved names: run, get, alias, hosts, list, trust, and proxy are subcommands and cannot be used as app names directly. Use portless run <cmd> to infer the name, or portless --name <name> <cmd> to force any name including reserved ones.

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

Portless auto-injects --port and --host flags for frameworks that ignore the PORT env var: Vite , Astro , React Router , Angular , Expo , and React Native. SvelteKit uses Vite internally and is handled automatically.

For other frameworks that don't read PORT, pass the port manually:

• 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)

Safari can't find .localhost URLs

Safari relies on the system DNS resolver for .localhost subdomains, which may not resolve them on all macOS configurations. Chrome, Firefox, and Edge have built-in handling.

Fix:

sudo portless hosts sync    # Adds current routes to /etc/hosts
sudo portless hosts clean   # Remove entries later

Auto-syncs /etc/hosts for custom TLDs (e.g. --tld test). For .localhost, set PORTLESS_SYNC_HOSTS=1 to enable.

Browser shows certificate warning with --https

The local CA may not be trusted yet. Run:

sudo portless trust

This adds the portless local CA to your system trust store. After that, restart the browser.

Proxy loop (508 Loop Detected)

If your dev server proxies requests to another portless app (e.g. Vite proxying /api to api.myapp.localhost:1355), the proxy must rewrite the Host header. Without this, portless routes the request back to the original app, creating an infinite loop.

Fix: set changeOrigin: true in the proxy config (Vite, webpack-dev-server, etc.):

// vite.config.ts
proxy: {
  "/api": {
    target: "http://api.myapp.localhost:1355",
    changeOrigin: true,
    ws: true,
  },
}

Requirements

• Node.js 20+
• macOS, Linux, or Windows
• openssl (for --https cert generation; ships with macOS and most Linux distributions)

Weekly Installs

412

Repository

vercel-labs/portless

GitHub Stars

6.3K

First Seen

Feb 15, 2026

Security Audits

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Installed on

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