ngrok - Introspected tunnels to localhost

ngrok is a reverse proxy that creates a secure tunnel between from a public endpoint to a locally running web service. ngrok captures and analyzes all traffic over the tunnel for later inspection and replay. You can give this URL to anyone to allow them to try out a web site you're developing without doing any deployment.

It helps to temporarily share a website that is only running on your development machine, Debugging and understanding any web service by inspecting the HTTP traffic, Running networked services on machines that are firewalled off from the internet.