Ngrok is a free 3rd party service (with optional extra features available for a small fee) that allows you to "tunnel" your locally hosted websites to other users on the internet. In other words, Ngrok provides you with a unique URL that you can pass to along to another friend that allows them to see the website you're building locally on your Mac, without you needing to upload it to a server on the internet.
It's a great way for others to get a preview of what you're working on. Or, you can use the URL to test your website on a mobile device.
VirtualHostX integrates with Ngrok's free tier service. This mean that you're only allowed one tunnel connection at a time. Support for paid Ngrok plans (with higher connection limits) is a feature we're still exploring.
To generate an Ngrok URL for your website, just click the "Refresh" button next to the Ngrok URL field. You can then copy and paste that link to another device or person elsewhere on the internet.