ngrok is a tool that creates tunnels between networks, allowing developers to expose local ports to the public Internet and secure traffic from the Internet to production cloud environments. The tutorial covers how to verify Svix webhook requests using ngrok both for local development and on ngrok Cloud Edge, assuming familiarity with Svix webhooks service and ngrok. It provides step-by-step instructions on installing ngrok CLI, creating a tunnel, and verifying Svix webhooks locally, as well as setting up an ngrok Cloud Edge to verify Svix webhooks securely.