portless

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

- "dev": "next dev"                  # http://localhost:3000
+ "dev": "portless run next dev"     # https://myapp.localhost

portless runs a local reverse proxy and gives each dev server a name. Your app listens on a free port that portless assigns, and you open https://<name>.localhost instead of remembering which port it took. The URL stays the same across restarts, so bookmarks, cookies, OAuth redirects, and an agent's test script keep pointing at the right app.

Install

npm install -g portless

To pin the version per project, install it as a dev dependency with npm install -D portless. portless is pre-1.0, so contributors may run different versions, and a change to the state directory format between releases can require running portless trust again.

Quick start

From a project with a "dev" script in package.json:

portless
# -> runs "dev", https://<project>.localhost

The name comes from package.json, the git root, or the directory. Pass a name and a command to choose both:

portless myapp next dev
# -> https://myapp.localhost

• The proxy starts on the first run. It serves HTTPS with HTTP/2 on port 443, so the first run creates a local certificate authority, adds it to the system trust store, and may ask for sudo. Use --no-tls for plain HTTP, or --unprivileged to skip sudo (Unprivileged mode).
• portless run <cmd> infers the name and detects git worktrees. In a linked worktree, the last / segment of the branch becomes a subdomain, so fix-ui.myapp.localhost and myapp.localhost run side by side. Use --prefix or PORTLESS_PREFIX to set the label, or configure the label style and hostname template.
• A name with dots is a subdomain: portless api.myapp pnpm start serves https://api.myapp.localhost.
• PORTLESS=0 pnpm dev runs the command directly, without the proxy.

The full walkthrough is in Getting started.

How it works

Each app gets a random port from 4000 to 4999 through the PORT environment variable, and registers a route from its hostname to that port. The proxy forwards https://<name>.localhost to the route. Most frameworks read PORT. For those that don't, such as Vite, Astro, Angular, Expo, and Wrangler, portless adds the matching port and host flags to the command (Port assignment).

Outside LAN mode, the proxy listens only on 127.0.0.1 and ::1. It keeps /etc/hosts in sync for route hostnames, which custom TLDs such as .test need. If a route hostname will not resolve, the command that registered it warns and points you to portless hosts sync.

To reach an app from another device or share it, use LAN mode for phones on the same network, or Tailscale, ngrok, or a Cloudflare quick tunnel with --tailscale, --ngrok, or --cloudflare.

Configuration

An optional portless.json sets the name and script. In a monorepo, one file at the root covers every workspace package, and portless from the root starts all of them:

{
  "apps": {
    "apps/web": { "name": "myapp" },
    "apps/api": { "name": "api.myapp" }
  }
}

A "portless" key in package.json works too. Fields, precedence, Turborepo setup, and environment variables are in Configuration.

For AI agents

Install the portless skill into an agent harness from skills.sh:

npx skills add vercel-labs/portless

For MCP clients, portless mcp starts an MCP server over stdio. The default core profile lists routes, looks up URLs, and manages static aliases. --tools all adds proxy control and diagnostics:

{ "mcpServers": { "portless": { "command": "portless", "args": ["mcp"] } } }

The server does not start dev servers. Agents run portless run <cmd> in a shell. See MCP server.

Commands

Run portless --help for the full list, or portless <command> --help for one command.

Group	Commands	Docs
Run apps	portless, run, <name> <cmd>, get	Run an app, Get a service URL
Static routes	alias, compose up, compose down	Alias, Docker Compose
Proxy	proxy start, proxy stop, service install, service status, service uninstall	Proxy control, OS startup service
HTTPS and DNS	trust, hosts sync, hosts clean	HTTPS, Hosts
Inspect and clean up	list, doctor, prune, clean	Doctor, Prune orphans, Clean up
Agents	mcp	MCP server

Run portless doctor first when a URL does not load. It checks the proxy, routes, DNS, and CA trust without changing anything, and prints suggested fixes.

Platforms

portless runs on macOS, Linux, and Windows with Node.js 24 or later. --tailscale and --funnel need the Tailscale CLI, --ngrok needs the ngrok CLI, and --cloudflare needs cloudflared.

Development

This repo is a pnpm workspace with Turborepo. The published package is packages/portless/, and the docs site is apps/docs/. Use Node.js 24 or later and pnpm 11:

pnpm install
pnpm build
pnpm test
pnpm lint
pnpm type-check
pnpm format

AGENTS.md lists the files to update with each change and the release process.

Documentation

• portless.sh: getting started, commands, HTTPS, and configuration
• Why portless: the problems named URLs solve
• Changelog

License

Apache-2.0