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Streamlining Local Development with Portless by Vercel Labs

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Stop Fighting Localhost Ports --- This Tool Fixes It

If you work on multiple projects locally, you already know the pain.

localhost:3000 localhost:3001 localhost:5173 localhost:8080

After opening a few tabs you completely lose track.

Which one is the frontend?
Which one is the API?
Which one is the docs server?

And the moment you start another project...

Boom --- port conflict.

Your dev server crashes, and you start hunting for the next available port.

I've dealt with this for years, especially while working on monorepos and multiple services locally.

Then I found Portless by Vercel Labs, and it completely changes how localhost works.

The Idea Is Surprisingly Simple

Instead of using ports to identify apps, Portless uses subdomains.

So instead of this:

localhost:3000 localhost:3001 localhost:3002

You get:

http://myapp.localhost:1355 http://api.myapp.localhost:1355 http://docs.myapp.localhost:1355

Now every service has a clear name.

No guessing.
No remembering ports.

What Problems It Actually Solves

After using it for a bit, I realized how many annoying issues it quietly fixes.

1. Port conflicts disappear

Running five projects at once normally means juggling ports.

With Portless, everything runs behind one stable gateway port.

No more:

"Something is already running on port 3000"

2. No more cookie or storage bleeding

Different apps on different ports sometimes share cookies or storage in weird ways.

Subdomains isolate everything properly.

Your API, frontend, and admin dashboard behave like real production domains.

3. Tabs are finally understandable

When you have multiple tabs open, seeing:

localhost:3000 localhost:3001 localhost:3002

is useless.

But seeing:

api.myapp.localhost docs.myapp.localhost admin.myapp.localhost

makes everything obvious.

4. Perfect for monorepos

In a monorepo setup you might have:

  • frontend
  • API
  • documentation
  • admin panel
  • worker dashboard

Portless makes them feel like a real microservice environment locally.

5. Git worktrees get their own subdomains

If you use Git worktrees for multiple branches, Portless automatically gives each branch its own subdomain.

That means you can run multiple versions of the same app side‑by‑side.

The AI / Agent Development Angle

Coding agents often hardcode ports like:

localhost:3000

If the port changes, everything breaks.

With Portless:

api.project.localhost frontend.project.localhost

Agents always know exactly where to go.

It removes a surprising amount of friction when building AI-powered developer tools.

It Works With Almost Everything

Portless works with:

  • Next.js
  • Vite
  • Express
  • Nuxt
  • React Router
  • Angular
  • Expo

Basically any dev server.

Getting Started

Install globally:

npm install -g portless

Run your dev server:

portless run next dev

That's it.

Project Stats

  • ⭐ ~3.8k stars on GitHub
  • 📦 Version: v0.5.2
  • 🛠 Maintained by Vercel Labs

Links

GitHub
https://github.com/vercel-labs/portless

Website
https://port1355.dev/

Final Thoughts

Local development hasn't evolved much in years.

We've just accepted the chaos of random ports and broken setups.

Portless fixes that elegantly.

If you run multiple services locally --- or build tools for AI agents --- this tool is worth trying.

You might never go back to localhost:3000.