localtunnel

Localtunnel is an open-source command-line tool that exposes a port on the developer’s local machine to the public internet by creating a secure tunnel to a remote server. It enables developers to share locally hosted web services, APIs, or demos without deploying to a public server. The public URL is generated by the tunnel service and typically points to a domain such as a subdomain of a localtunnel-friendly address; the exact domain or subdomain may vary.

The client is a Node.js-based program. To use it, install the package globally with npm install -g localtunnel, then run a command such as lt --port 3000. The tool connects to a tunnel server and forwards incoming requests on the public URL to the specified local port. Users can often request a specific subdomain with --subdomain if the name is available, or rely on an automatically assigned URL. Localtunnel supports common web traffic, including HTTP, HTTPS, and WebSocket traffic.

Localtunnel is commonly used for rapid development and testing, webhooks, and demos, allowing collaborators or external services to reach a locally running application. It is an alternative to other tunneling services and is valued for its simplicity and open-source nature. However, it introduces security considerations since it exposes a local host to the internet; users should forward only necessary services and be mindful of access controls and data exposure. The project remains hosted with its source code on public repositories, where users can review changes and contribute.

See also: Ngrok, PageKite, Frp, OpenSSH local port forwarding.