Named HTTPS .localhost URLs for local development with portless (v0.10.x). Eliminates port collisions, enables stable URLs for agents, integrates with emulate for API emulation aliases, git worktrees for branch-named subdomains, and LAN mode (--lan) for mDNS .local hostnames reachable across devices. Use when setting up local dev environments, configuring agent-accessible URLs, running multi-service dev setups, or testing from phones/tablets on the same wifi. Do NOT use for production deployments, CI environments (set PORTLESS=0), or DNS/hosting configuration.

Portless Integration

Named .localhost URLs for local development. Replaces localhost:3000 with https://myapp.localhost.

Full CLI reference: Load Read("${CLAUDE_SKILL_DIR}/references/upstream.md") for complete command docs.

New in 2026-04 (portless 0.10.x)

HTTPS on 443 by default (breaking from 0.9.x http:1355). Valid cert, no setup. --no-tls reverts.
NODE_EXTRA_CA_CERTS auto-injected (0.10.2) into child processes — node HTTPS calls trust portless CA with zero setup.
--wildcard subdomains — https://*.myapp.localhost for multi-tenant / preview routing.
portless alias <name> <port> — map a docker-compose / emulate port to a named URL without a long-running run process.
portless clean — full teardown: stops proxy, removes CA, wipes state, cleans /etc/hosts.
--lan mode — mDNS .local hostnames reachable across wifi (phone, tablet, other machines) without router config.
Fixed app ports — --app-port 3000 / PORTLESS_APP_PORT for tools that need a known port (debuggers, docker).
hosts-sync on by default for Safari compat (disable with PORTLESS_SYNC_HOSTS=0).
HTTP/2 HMR fixes for Vite/VitePlus/Next.js dev — websocket upgrades no longer break under h2.
Expo / React Native support — portless run expo start gives Metro a stable URL for device QR codes.

When to Use

Starting a dev server that agents or browser tests will target
Running multiple services locally (API + frontend + docs)
Working in git worktrees (branch-named subdomains)
Local OAuth flows (stable callback URLs)
Connecting emulate API mocks to named URLs

Quick Start

# Instead of: npm run dev (random port)
portless run npm run dev
# → https://myapp.localhost (stable, named, HTTPS on 443 — default in 0.10+)

# Multi-service
portless run --name api npm run dev:api
portless run --name web npm run dev:web
# → https://api.localhost, https://web.localhost

# LAN mode (0.10.0) — reachable from phone/tablet via mDNS
portless proxy start --lan
portless run npm run dev
# → https://myapp.local (resolves across the local network, no router config)

# Full teardown (0.10.1) — stops proxy, removes CA, wipes state, cleans /etc/hosts
portless clean

0.10.x breaking change: default switched from http://app.localhost:1355 to https://app.localhost on port 443. Use --no-tls to revert. NODE_EXTRA_CA_CERTS is injected into child processes automatically (0.10.2) — no manual cert setup. /etc/hosts is synced automatically for Safari; disable with PORTLESS_SYNC_HOSTS=0.

Framework-Specific Setup

Load Read("${CLAUDE_SKILL_DIR}/references/framework-integration.md") for full framework recipes.

Most frameworks (Next.js, Vite, Express) work with portless run <cmd>. Some need explicit flags:

Framework	Auto-detected?	Extra flags needed
Next.js	Yes	None
Vite / Astro	Yes	None
Express / Fastify / Hono	Yes	None (reads `PORT` env var)
Ruby on Rails	Yes	None
FastAPI / uvicorn	No	`--port $PORT --host $HOST`
Django	No	`$HOST:$PORT` positional arg

Why `.localhost`?

Feature	`.localhost` (RFC 6761)	`127.0.0.1:PORT`	`/etc/hosts` hack
No `/etc/hosts` editing	Yes	Yes	No
HTTPS with valid cert	Yes	No	Manual
Wildcard subdomains	Yes	No	No
Works in all browsers	Yes	Yes	Varies
Cookie isolation per service	Yes	No	Yes
No port conflicts	Yes	No	Yes

Key Environment Variables

When portless runs your command, it injects:

Variable	Value	Use in agents
`PORT`	Assigned ephemeral port (4000-4999)	Internal only
`HOST`	`127.0.0.1`	Internal only
`PORTLESS_URL`	`https://myapp.localhost`	Use this in agent prompts
`NODE_EXTRA_CA_CERTS`	Path to portless CA (auto-injected 0.10.2)	Child node processes trust portless certs without setup

Toggle env vars

Variable	Effect
`PORTLESS=0`	Bypass portless entirely (CI)
`PORTLESS_SYNC_HOSTS=0`	Disable auto `/etc/hosts` sync (default: on in 0.10.1+)
`PORTLESS_STATE_DIR`	Override state dir (default: `~/.portless` or `/tmp/portless` for privileged ports)

OrchestKit Integration Patterns

1. Agent-Accessible Dev Server

# Start with portless, then agents can target PORTLESS_URL
portless run npm run dev

# In ork:expect or agent-browser:
agent-browser open $PORTLESS_URL

2. Emulate + Portless (Named API Mocks)

# Register emulate ports as named aliases
portless alias github-api 4001
portless alias vercel-api 4000
portless alias google-api 4002

# Now agents can target:
#   https://github-api.localhost — GitHub emulator
#   https://vercel-api.localhost — Vercel emulator

3. Git Worktree Dev

# In worktree for feature/auth-flow:
portless run npm run dev
# → https://auth-flow.myapp.localhost (auto branch prefix)

4. Bypass in CI

# Disable portless in CI — direct port access
PORTLESS=0 npm run dev

Anti-Patterns

Don't	Do Instead
Hardcode `localhost:3000` in tests	Use `PORTLESS_URL` or `process.env.PORTLESS_URL`
Run portless in CI	Set `PORTLESS=0` in CI environments
Use numeric ports in AGENTS.md	Document the portless URL

References

File	Content
`references/upstream.md`	Full portless CLI reference (synced from Vercel)
`references/upstream-oauth.md`	OAuth callback patterns with stable URLs
`references/framework-integration.md`	Framework recipes (FastAPI, Django, Docker, gotchas)
`checklists/new-project-setup.md`	Step-by-step: add portless to a new project

portless