What is localhost:3000?

// works on your laptop. now let's make it work everywhere.

localhost is your computer, not the internet.

Open it and your browser talks back to your own machine.

  • 127.0.0.1 means “this computer.”
  • Nothing leaves your laptop.
  • Only you can open it.
your computer
your browser localhost = 127.0.0.1

localhost:3000 — famous on your laptop, invisible everywhere else.

:3000 is the app's door.

A port tells your computer which local app should answer.

  • Vite, Next.js, Astro, and Express use ports such as :3000 or :5173.
  • localhost:3000 means “this computer, app at door 3000.”
your computer one computer · many app doors

Choose where to publish it

Netlify Static sites and web apps with optional forms and server features. Explore Netlify Free plan availablePlans & pricing
Cloudflare Pages Static sites on Cloudflare’s network, with optional serverless functions. Explore Cloudflare Pages Free plan availablePlans & pricing
GitHub Pages Public project pages, portfolios, and documentation from a GitHub repository. Explore GitHub Pages Free for public repositoriesPlans & pricing
Vercel Framework apps built with Next.js and other modern tools. Explore Vercel Free for personal, non-commercial usePlans & pricing
Firebase Hosting Static and single-page apps, with Firebase services for login and stored data. Explore Firebase Hosting Free Spark planPlans & pricing
Azure Static Web Apps Static web apps with APIs, authentication, and Microsoft cloud integrations. Explore Azure Static Web Apps Free plan for personal projectsPlans & pricing
Railway Server apps, databases, and background jobs. Explore Railway Free plan · $1/mo usage creditPlans & pricing
Heroku Managed deployment for server apps and databases. Explore Heroku No free hosting planPlans & pricing
AWS Lightsail Virtual servers for people comfortable managing their own infrastructure. Explore AWS Lightsail No ongoing free plan · starter credits availablePlans & pricing

Quick answers

Can other people open localhost?

No. Their localhost points to their computer, not yours.

Does localhost need hosting?

Only when you want a public link. Hosting puts your files or app on an internet-connected server.

What's the quickest way to publish it?

Publish static files with a static host. If your project needs a server or database, choose an app host.