What is a Localhost Tunnel?
A localhost tunnel runs a small client next to your app that connects out to a relay service. The relay gives the app a reachable address, often a random subdomain, and forwards requests to it. ngrok, Cloudflare quick tunnels, Tailscale Funnel, and localtunnel all work this way.
The outbound connection means no router or firewall changes, but the resulting address is usually public: anyone who has or finds it can send the app requests unless the service adds access control.
How LayerV Implements This
The qURL CLI also connects out from your machine, but the app’s address answers no one by default. Each recipient gets a signed access link that opens one session, scoped to the network it was opened from, and expires; by protocol design, other requests get no response.