npm install ngrok
var ngrok = require('ngrok');
ngrok.connect(function (err, url) {});

or

npm install ngrok -g
ngrok http 8080

You can create basic http-https-tcp tunnel without authtoken. For custom subdomains and more you should obtain authtoken by signing up at ngrok.com. Once you set it, it's stored in ngrok config and used for all tunnels. Few ways:

ngrok.authtoken(token, function(err, token) {});
ngrok.connect({authtoken: token, ...}, function (err, url) {});
ngrok authtoken <token>

var ngrok = require('ngrok');

ngrok.connect(function (err, url) {}); // https://757c1652.ngrok.io -> http://localhost:80
ngrok.connect(9090, function (err, url) {}); // https://757c1652.ngrok.io -> http://localhost:9090
ngrok.connect({proto: 'tcp', addr: 22}, function (err, url) {}); // tcp://0.tcp.ngrok.io:48590
ngrok.connect(opts, function(err, url) {});

ngrok.connect({
	proto: 'http', // http|tcp|tls
	addr: 8080, // port or network address
	auth: 'user:pwd', // http basic authentication for tunnel
	subdomain: 'alex', // reserved tunnel name https://alex.ngrok.io
	authtoken: '12345', // your authtoken from ngrok.com
	region: 'us' // one of ngrok regions (us, eu, au, ap), defaults to us,
	configPath: '~/git/project/ngrok.yml' // custom path for ngrok config file
}, function (err, url) {});

Other options: name, inspect, host_header, bind_tls, hostname, crt, key, client_cas, remote_addr - read here

Note on regions: region used in first tunnel will be used for all next tunnels too.

The ngrok and all tunnels will be killed when node process is done. To stop the tunnels use

ngrok.disconnect(url); // stops one
ngrok.disconnect(); // stops all
ngrok.kill(); // kills ngrok process

Note on http tunnels: by default bind_tls is true, so whenever you use http proto two tunnels are created - http and https. If you disconnect https tunnel, http tunnel remains open. You might want to close them both by passing http-version url, or simply by disconnecting all in one go ngrok.disconnect().

Also you can use ngrok as an event emitter, it fires "connect", "disconnect" and "error" events

ngrok.once('connect', function (url) {};
ngrok.connect(port);

You can use ngrok's configurations files, and just pass name option when making a tunnel. Configuration files allow to store tunnel options. Ngrok looks for them here:

OS X	/Users/example/.ngrok2/ngrok.yml
Linux	/home/example/.ngrok2/ngrok.yml
Windows	C:\Users\example\.ngrok2\ngrok.yml

You can specify a custom configPath when making a tunnel.

When tunnel is established you can use the ngrok interface http://127.0.0.1:4040 to inspect the webhooks done via ngrok.

npm install downloads ngrok binaries for you platform and puts them into bin folder. You can host binaries yourself and set NGROK_CDN_URL env var before installing ngrok. Or you can force specific arch by setting NGROK_ARCH, eg NGROK_ARCH=freebsdia32

First time you create tunnel ngrok process is spawned and runs until you disconnect or when parent process killed. All further tunnels are created or stopped by using internal ngrok api which usually runs on http://127.0.0.1:4040

Please run git update-index --assume-unchanged bin/ngrok to not override ngrok stub in your pr. Unfortunately it can't be gitignored.