ngrok creates a tunnel from the public internet ( http://subdomain.ngrok.com ) to a port on your local machine. You can give this URL to anyone to allow them to try out a web site you're developing without doing any deployment.
ngrok captures all traffic through the tunnel. It displays information about the HTTP traffic for your inspection. Raw request/response bytes, parsed headers and form data, JSON/XML syntax checking and more are included.
Developing services which consume webhooks can be challenging if the hooks are labor-intensive to generate. Use ngrok's replay request feature to iterate quickly on a new feature without switching contexts to generate new requests.