Cloudflare has added email authentication to Quick Tunnels, its temporary links to services running on a developer's machine.
From cloudflared 2026.9.3, the --allowed-mail flag accepts individual addresses or domains. Visitors enter their email and a one-time PIN; neither side needs a Cloudflare account. The local connector checks the guest list, and access ends when the tunnel process stops.
cloudflared tunnel --url http://localhost:8080 \
--allowed-mail [email protected]
For an early demo, this separates sharing from deployment. A colleague can see the app already running locally, without a new staging build or a login flow in the app itself.
It serves a different purpose from repeatable CI testing: a protected preview is a way to show someone the current work, not a replacement for validation. Leave out the flag and the tunnel remains public.
The feature was announced on 2 October. Cloudflare says email protection is free, as Quick Tunnels already are.