---
title: "Why Portless"
description: "Replace port numbers with stable, named .localhost URLs. For humans and agents."
canonical_url: "https://portless.sh/why"
---
# Why Portless

Local dev with port numbers is fragile. Portless fixes that by giving each dev server a stable, named `.localhost` URL.

## Port conflicts

Two projects default to the same port and you get `EADDRINUSE`. With portless, each app gets an auto-assigned port behind a named URL. No collisions.

## Memorizing ports

Was the API on 3001 or 8080? With portless, it is always `https://api.localhost`.

## Wrong app on refresh

Stop one server, start another on the same port, and your open tab shows something completely different. Named URLs eliminate this.

## Monorepo multiplier

Every problem above scales with each service in the repo. Portless handles any number of services with distinct hostnames.

## Agents test the wrong port

AI coding agents guess or hardcode the wrong port, especially in monorepos. A stable URL like `https://myapp.localhost` is deterministic and reliable.

## Cookie and storage clashes

Cookies set on `localhost` bleed across apps on different ports. `localStorage` is lost when ports shift. Each `.localhost` subdomain gets its own scope.

## Hardcoded ports in config

CORS allowlists, OAuth redirect URIs, and `.env` files all break when ports change. With portless, URLs are stable across restarts.

## Sharing URLs with teammates

"What port is that on?" becomes a Slack question. With portless, everyone uses the same named URL.

## Browser history

Your history for `localhost:3000` is a jumble of unrelated projects. Named URLs keep things organized.