localtunnel

What is localtunnel?

The localtunnel npm package allows you to expose your localhost to the world for easy testing and sharing. It creates a publicly accessible URL that proxies all requests to your locally running webserver.

What are localtunnel's main functionalities?

Expose local server to the internet

This feature allows you to expose a local server running on a specific port to the internet by creating a tunnel. The code sample demonstrates how to create a tunnel to a local server running on port 3000 and log the public URL to the console.

const localtunnel = require('localtunnel');

(async () => {
  const tunnel = await localtunnel({ port: 3000 });

  // the assigned public url for your tunnel
  // i.e. https://abcdefgjhij.localtunnel.me
  console.log(tunnel.url);

  tunnel.on('close', () => {
    // tunnels are closed
  });
})();

Specify subdomain

This feature allows you to request a specific subdomain for your tunnel, making the URL easier to remember and share. The code sample shows how to request a tunnel with a custom subdomain.

const localtunnel = require('localtunnel');

(async () => {
  const tunnel = await localtunnel({ port: 3000, subdomain: 'mycustomsubdomain' });

  console.log(tunnel.url);
})();

Close the tunnel

This feature allows you to programmatically close the tunnel when you are done with it. The code sample demonstrates how to close the tunnel.

const localtunnel = require('localtunnel');

(async () => {
  const tunnel = await localtunnel({ port: 3000 });

  console.log(tunnel.url);

  // When you are done with the tunnel
  tunnel.close();
})();

Other packages similar to localtunnel

ngrok

Ngrok is a popular tool that provides similar functionality to localtunnel. It creates secure tunnels to localhost and offers features like custom domains, reserved subdomains, and encrypted tunnels. Ngrok also has a paid version with additional features.

serveo

Serveo is an SSH server just for remote port forwarding. It works using existing SSH functionality, so there's no need to install a client. However, as of my knowledge cutoff in 2023, Serveo has been temporarily disabled due to phishing abuse.

README

localtunnel

localtunnel exposes your localhost to the world for easy testing and sharing! No need to mess with DNS or deploy just to have others test out your changes.

Great for working with browser testing tools like browserling or external api callback services like twilio which require a public url for callbacks.

Quickstart

npx localtunnel --port 8000

Installation

Globally

npm install -g localtunnel

As a dependency in your project

yarn add localtunnel

CLI usage

When localtunnel is installed globally, just use the lt command to start the tunnel.

lt --port 8000

Thats it! It will connect to the tunnel server, setup the tunnel, and tell you what url to use for your testing. This url will remain active for the duration of your session; so feel free to share it with others for happy fun time!

You can restart your local server all you want, lt is smart enough to detect this and reconnect once it is back.

Arguments

Below are some common arguments. See lt --help for additional arguments

• --subdomain request a named subdomain on the localtunnel server (default is random characters)
• --local-host proxy to a hostname other than localhost

You may also specify arguments via env variables. E.x.

PORT=3000 lt

API

The localtunnel client is also usable through an API (for test integration, automation, etc)

localtunnel(port [,options][,callback])

Creates a new localtunnel to the specified local port. Will return a Promise that resolves once you have been assigned a public localtunnel url. options can be used to request a specific subdomain. A callback function can be passed, in which case it won't return a Promise. This exists for backwards compatibility with the old Node-style callback API. You may also pass a single options object with port as a property.

const localtunnel = require('localtunnel');

(async () => {
  const tunnel = await localtunnel({ port: 3000 });

  // the assigned public url for your tunnel
  // i.e. https://abcdefgjhij.localtunnel.me
  tunnel.url;

  tunnel.on('close', () => {
    // tunnels are closed
  });
})();

options

• port (number) [required] The local port number to expose through localtunnel.
• subdomain (string) Request a specific subdomain on the proxy server. Note You may not actually receive this name depending on availability.
• host (string) URL for the upstream proxy server. Defaults to https://localtunnel.me.
• local_host (string) Proxy to this hostname instead of localhost. This will also cause the Host header to be re-written to this value in proxied requests.
• local_https (boolean) Enable tunneling to local HTTPS server.
• local_cert (string) Path to certificate PEM file for local HTTPS server.
• local_key (string) Path to certificate key file for local HTTPS server.
• local_ca (string) Path to certificate authority file for self-signed certificates.
• allow_invalid_cert (boolean) Disable certificate checks for your local HTTPS server (ignore cert/key/ca options).

Refer to tls.createSecureContext for details on the certificate options.

Tunnel

The tunnel instance returned to your callback emits the following events

event	args	description
request	info	fires when a request is processed by the tunnel, contains method and path fields
error	err	fires when an error happens on the tunnel
close		fires when the tunnel has closed

The tunnel instance has the following methods

method	args	description
close		close the tunnel

other clients

Clients in other languages

go gotunnelme

go go-localtunnel

C#/.NET localtunnel-client

server

See localtunnel/server for details on the server that powers localtunnel.

License

MIT