What is Ngrok?
Ngrok is a multiplatform tunneling, reverse proxy software that establishes secure tunnels from a public endpoint such as the internet to a locally running network service while capturing all traffic for detailed inspection and replay.
How does it work?
You download and run a program on your machine and provide it the port of a network service, usually a web server.
It connects to the ngrok cloud service which accepts traffic on a public address and relays that traffic through to the ngrok process running on your machine and then on to the local address you specified.