portless

Named .localhost URLs for dev servers, eliminating port conflicts and hardcoded port numbers. Assigns random free ports (4000–4999) automatically and routes named subdomains (e.g. myapp.localhost:1355 ) to the correct app via a reverse proxy on port 1355 Auto-detects git worktrees and prepends branch names as subdomain prefixes so each worktree gets a unique URL without configuration changes Supports HTTP/2 with HTTPS via auto-generated local CA certificates; includes CLI commands for proxy management, static route registration, and /etc/hosts syncing for Safari compatibility Auto-injects --port and --host flags for frameworks that ignore the PORT environment variable (Vite, Astro, React Router, Angular, Expo, React Native)

INSTALLATION
npx skills add https://github.com/vercel-labs/portless --skill portless
Run in your project or agent environment. Adjust flags if your CLI version differs.

SKILL.md

$2a

# Global (available everywhere)

npm install -g portless

# Or per-project dev dependency

npm install -D portless

When installed per-project, invoke via package.json scripts or npx portless (since the package is local, npx will not download anything).

Quick Start

# Install globally (or add -D to a project)

npm install -g portless

# Run your app (auto-starts the HTTPS proxy on port 443)

portless run next dev

# -> https://<project>.localhost

# Or with an explicit name

portless myapp next dev

# -> https://myapp.localhost

The proxy auto-starts when you run an app. You can also start it explicitly with portless proxy start. Auto-start reuses the configuration (port, TLS, TLD) from the most recent proxy run, so a restart or reboot does not silently revert to defaults. Explicit env vars always take priority.

In non-interactive environments (no TTY, or CI=1), portless exits with a descriptive error instead of prompting. Task runners like turborepo should pre-start the proxy.

Integration Patterns

Zero-config (recommended)

Bare portless works out of the box. It runs the "dev" script from package.json through the proxy, inferring the app name from the package name, git root, or directory:

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

pnpm dev        # -> works without portless, plain "next dev"

Use an optional portless.json to override defaults (name, script, port):

{ "name": "myapp" }
portless        # -> runs "dev" script, https://myapp.localhost

Monorepo

One portless.json at the repo root. Portless discovers packages from pnpm-workspace.yaml, or the "workspaces" field in package.json (npm, yarn, bun):

{

  "apps": {

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

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

  }

}
portless                  # from repo root: start all packages with a "dev" script

cd apps/web &#x26;&#x26; portless   # start just one package

portless --script start   # run "start" instead of "dev"

The apps map is optional and only provides name overrides. Unlisted packages auto-discover with inferred names.

Without an apps map, hostnames follow <package>.<project>.localhost. The project name comes from the most common npm scope (e.g. @myorg/web and @myorg/api produce myorg), falling back to the workspace root directory name. If a package's short name matches the project name, it uses the bare <project>.localhost.

Turborepo

For turborepo projects, use portless as the dev script with the real command in a separate script:

{

  "scripts": { "dev": "portless", "dev:app": "next dev" },

  "portless": { "name": "myapp", "script": "dev:app" }

}

pnpm dev runs turbo, which runs portless in each package. Portless detects the package manager and runs pnpm run dev:app through the proxy.

package.json scripts

You can still use portless directly in 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          # https://myapp.localhost

portless api.myapp pnpm start    # https://api.myapp.localhost

portless docs.myapp next dev     # https://docs.myapp.localhost

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 routes to the myapp app). 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   # -> https://myapp.localhost

# Linked worktree on branch "fix-ui"

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

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

  • portless proxy start starts an HTTPS reverse proxy on port 443 as a background daemon. Auto-elevates with sudo on macOS/Linux; falls back to port 1355 if sudo is unavailable. Use --no-tls for plain HTTP on port 80. Configurable with -p / --port or the PORTLESS_PORT env var. The proxy also auto-starts when you run an app.
  • portless <name> <cmd> assigns a random free port (4000-4999) via the PORT env var and registers the app with the proxy
  • The browser hits https://<name>.localhost; 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 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, VitePlus, Astro, React Router, Angular, Expo, React Native), portless auto-injects the correct --port flag and, when needed, a matching --host CLI flag.

State directory

Portless stores its state (routes, PID file, port file) in ~/.portless. Override with the PORTLESS_STATE_DIR environment variable.

Environment variables

Variable

Description

PORTLESS_PORT

Override the default proxy port (default: 443 with HTTPS, 80 without)

PORTLESS_APP_PORT

Use a fixed port for the app (skip auto-assignment)

PORTLESS_HTTPS

HTTPS on by default; set to 0 to disable (same as --no-tls)

PORTLESS_LAN

Set to 1 to always enable LAN mode (auto-detects LAN IP)

PORTLESS_TLD

Use a custom TLD instead of localhost (e.g. test)

PORTLESS_WILDCARD

Set to 1 to allow unregistered subdomains to fall back to parent

PORTLESS_SYNC_HOSTS

Set to 0 to disable auto-sync of /etc/hosts (on by default)

PORTLESS_TAILSCALE

Set to 1 to share apps on your Tailscale network (same as --tailscale)

PORTLESS_FUNNEL

Set to 1 to share apps publicly via Tailscale Funnel (same as --funnel)

PORTLESS_STATE_DIR

Override the state directory

PORTLESS=0

Bypass the proxy, run the command directly

HTTP/2 + HTTPS

HTTPS with HTTP/2 is enabled by default (faster page loads for dev servers with many files). First run generates a local CA and adds it to the system trust store. After that, no prompts and no browser warnings.

portless proxy start --cert ./c.pem --key ./k.pem  # Use custom certs

portless proxy start --no-tls                       # Disable HTTPS (plain HTTP)

portless trust                                      # Add CA to trust store later

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.

LAN mode

portless proxy start --lan

portless proxy start --lan --https

portless proxy start --lan --ip 192.168.1.42

--lan advertises <name>.local hostnames over mDNS so any device on the same Wi-Fi can reach your apps. Portless auto-detects your LAN IP and follows network changes automatically, but you can pin a specific address with --ip <address> or the PORTLESS_LAN_IP environment variable. Set PORTLESS_LAN=1 to default to LAN mode every time the proxy starts.

Portless remembers LAN mode via proxy.lan, so if you stop a LAN proxy and start again, it stays in LAN mode. All proxy settings (port, TLS, TLD, LAN) are persisted and reused on auto-start unless overridden by explicit flags or env vars. Use PORTLESS_LAN=0 for one start to switch back to .localhost mode. If a proxy is already running with different explicit LAN/TLS/TLD settings, portless warns and asks you to stop it first.

LAN mode depends on the system mDNS helpers that portless launches: macOS includes dns-sd, while Linux uses avahi-publish-address from avahi-utils (install via sudo apt install avahi-utils or your distro’s tooling).

-

Next.js: add your .local hostnames to allowedDevOrigins:

// next.config.js

module.exports = {

  allowedDevOrigins: ["myapp.local", "*.myapp.local"],

};

-

Expo / React Native: portless always injects --port. React Native also gets --host 127.0.0.1. Expo gets --host localhost outside LAN mode, but in LAN mode portless leaves Metro on its default LAN host behavior instead of forcing --host or HOST.

Tailscale sharing

Share dev servers with teammates on your Tailscale network using --tailscale, or expose to the public internet with --funnel:

portless myapp --tailscale next dev

# -> https://myapp.localhost           (local)

# -> https://devbox.yourteam.ts.net    (tailnet)

portless myapp --funnel next dev

# -> https://myapp.localhost           (local)

# -> https://devbox.yourteam.ts.net    (public internet)

Tailscale HTTPS certificates must be enabled before --tailscale or --funnel can register HTTPS URLs. Funnel must also be enabled for the tailnet and node before --funnel can register the public URL. If either setting is missing, portless exits before starting the child process.

Each --tailscale app is root-mounted on its own Tailscale HTTPS port (443, then 8443, 8444, etc.) so no framework basePath configuration is needed. Set PORTLESS_TAILSCALE=1 to share every app by default. portless list shows both local and tailnet URLs. Tailscale serve registrations are cleaned up when the app exits. Requires tailscale CLI installed and connected, with Tailscale HTTPS certificates enabled.

OS startup service

Use the service command when users want the proxy to start automatically after reboot:

portless service install

portless service status

portless service uninstall

The service uses the default clean URL behavior: HTTPS on port 443 with .localhost names. macOS and Linux install a root-owned service so port 443 can bind at boot. Windows installs a Task Scheduler startup task that runs as SYSTEM. Installation and removal may require administrator privileges. portless clean automatically removes the service.

CLI Reference

Command

Description

portless

Run dev script through proxy

portless

From monorepo root: run all workspace packages

portless --script <name>

Run a specific package.json script (default: dev)

portless run [cmd] [args...]

Infer name from project, run through proxy (auto-starts)

portless run --name <name> <cmd>

Override inferred base name (worktree prefix still applies)

portless <name> <cmd> [args...]

Run app at https://<name>.localhost (auto-starts proxy)

portless get <name>

Print URL for a service (for cross-service wiring)

portless get <name> --no-worktree

Print URL without worktree prefix

portless list

Show active routes

portless trust

Add local CA to system trust store (for HTTPS)

portless clean

Remove state, CA trust entry, and /etc/hosts block

portless prune

Kill orphaned dev servers from crashed sessions

portless prune --force

Kill orphans with SIGKILL instead of SIGTERM

portless proxy start

Start HTTPS proxy as a daemon (port 443, auto-elevates)

portless proxy start --no-tls

Start without HTTPS (plain HTTP on port 80)

portless proxy start --lan

Start in LAN mode (mDNS .local, auto-follows LAN IP changes)

portless proxy start -p <number>

Start the proxy on a custom port

portless proxy start --tld test

Use .test instead of .localhost

portless proxy start --foreground

Start the proxy in foreground (for debugging)

portless proxy start --wildcard

Allow unregistered subdomains to fall back to parent route

portless proxy stop

Stop the proxy

portless service install

Start the HTTPS proxy when the OS starts

portless service status

Show service and proxy status

portless service uninstall

Remove the startup service

portless alias <name> <port>

Register a static route (e.g. for Docker containers)

portless alias <name> <port> --force

Overwrite an existing route

portless alias --remove <name>

Remove a static route

portless hosts sync

Add routes to /etc/hosts (fixes Safari)

portless hosts clean

Remove portless entries from /etc/hosts

portless <name> --app-port <n> <cmd>

Use a fixed port for the app instead of auto-assignment

portless <name> --tailscale <cmd>

Share the app on your Tailscale network (tailnet)

portless <name> --funnel <cmd>

Share the app publicly via Tailscale Funnel

portless <name> --force <cmd>

Kill the existing process and take over its route

portless --name <name> <cmd>

Force <name> as app name (bypasses subcommand dispatch)

portless <name> -- <cmd> [args...]

Stop flag parsing; everything after -- is passed to child

portless --help / -h

Show help

portless run --help

Show help for a subcommand (also: alias, hosts, clean)

portless --version / -v

Show version

Reserved names: run, get, alias, hosts, list, trust, clean, prune, proxy, and service 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.

portless.json

Optional config file. Portless looks for it in the current directory.

Field

Type

Default

Description

name

string

inferred from package.json

Base app name (worktree prefix still applies)

script

string

"dev"

Name of a package.json script to run

appPort

number

auto-assigned

Fixed port for the child process

proxy

boolean

auto-detected

Whether to route through the proxy (false for tasks)

apps

object

Overrides for workspace packages, keyed by relative path

turbo

boolean

true

Set false to use direct spawning instead of turborepo

Each apps entry has the same shape (name, script, appPort, proxy). When apps is present, top-level fields apply only in single-app mode.

package.json "portless" key

Instead of a separate portless.json, you can add a "portless" key to your package.json. A string value is shorthand for setting the name:

{ "portless": "myapp" }

An object supports all per-app fields (name, script, appPort, proxy):

{ "portless": { "name": "myapp", "script": "dev:app" } }

Precedence (closest wins): CLI flags > package.json "portless" key > portless.json app entry > defaults.

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 the right --port flag and, when needed, a matching --host flag for frameworks that ignore the PORT env var: Vite, VitePlus (vp), 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

The default ports (80 for HTTP, 443 for HTTPS) require sudo on macOS and Linux. Portless auto-elevates with sudo when needed. If sudo is unavailable, it falls back to port 1355 (no sudo needed). On Windows, no elevation is required.

portless proxy start --https           # Auto-elevates with sudo for port 443

portless proxy start -p 1355 --https   # No sudo needed (URLs include :1355)

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:

portless hosts sync    # Adds current routes to /etc/hosts

portless hosts clean   # Remove entries later

Auto-syncs /etc/hosts for route hostnames by default. Set PORTLESS_SYNC_HOSTS=0 to disable.

Browser shows certificate warning with --https

The local CA may not be trusted yet. Run:

portless trust

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

Remove portless from the machine

portless clean

Stops the proxy if needed, removes the portless CA from the trust store (when portless added it), deletes known files under state directories, and removes the portless /etc/hosts block. May require sudo on macOS/Linux.

Proxy loop (508 Loop Detected)

If your dev server proxies requests to another portless app (e.g. Vite proxying /api to api.myapp.localhost), 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: "https://api.myapp.localhost",

    changeOrigin: true,

    ws: true,

  },

}

Portless automatically sets NODE_EXTRA_CA_CERTS in child processes so Node.js trusts the portless CA. If you run a separate Node.js process outside portless, point it at the CA manually: NODE_EXTRA_CA_CERTS=~/.portless/ca.pem. Alternatively, use --no-tls for plain HTTP.

Tailscale not working

If --tailscale or --funnel fails:

tailscale status     # Check if connected

tailscale up         # Connect to your tailnet

Requires the Tailscale CLI to be installed (https://tailscale.com/download) and on PATH.

Requirements

  • Node.js 20+
  • macOS, Linux, or Windows
  • openssl (for --https cert generation; ships with macOS and most Linux distributions; on Windows, install via winget install -e --id ShiningLight.OpenSSL.Dev or use the copy bundled with Git for Windows)
  • tailscale CLI (optional, for --tailscale and --funnel)
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