Portless overview

Open source (Apache-2.0) by Vercel Labs — github.com/vercel-labs/portless (npm `portless`; "for humans and agents"). Replaces local-dev port numbers with stable, named `.localhost` URLs so there are no port conflicts. Runs an HTTPS reverse proxy on port 443; each app registers a hostname→port route and is proxied to a randomly assigned port (4000–4999), so `http://localhost:3000` becomes `https://myapp.localhost`. HTTPS/HTTP-2 by default with auto-generated trusted local CA; auto-detects frameworks (Vite, Astro, React Router, …) and honors/injects `PORT`; auto-syncs `/etc/hosts`. Worktree-friendly: a git branch name is auto-prepended as a subdomain (`fix-ui.myapp.localhost`) with zero config, so parallel worktrees never collide on ports. Install `npm install -g portless` (Node 24+); run `portless` to wrap the package.json dev script, `portless myapp next dev`, or `portless api.myapp pnpm start` for sub-services. Custom TLD via `--tld test`.