Expose / tunnel localhost (Box)

Use this when a service running in a Box must be reachable from outside: sharing a dev preview, receiving webhooks, or demoing. Because the service already runs inside the VM, exposing it is one command — no ngrok-style sidecar, no extra account, no cert setup.

Recipe

box ssh "$box_id" -- "cd /app && PORT=3000 npm start &"   # MUST bind 0.0.0.0
box ssh "$box_id" -- "host 3000 --title preview"
box ssh "$box_id" -- "host url 3000"                       # -> https://<box>-3000.on.ascii.dev?_token=...
box ssh "$box_id" -- "host list"                           # manage; host hide <port> to revoke

Ascii terminates TLS for on.ascii.dev and proxies to the box. URLs are token-gated by default (--public drops the token, --private enforces it).

Why Box beats a tunnel tool