Sharing your local app

Add --tunnel to put the app you’re running locally on a public, encrypted URL:

npx flare dev --tunnel      # the dev server, with hot reload
npx flare start --tunnel    # the production build in workerd

  Public URL  https://chair-oclc-diff-discusses.trycloudflare.com
  Forwarding  http://localhost:3000

This uses Cloudflare Quick Tunnels. There’s no Cloudflare account to set up, no DNS records and no firewall ports to open. The URL changes each time you start the command, and the tunnel closes when you stop the server with Ctrl+C.

Use it to:

• show work in progress to a client or teammate;
• try the app on your phone;
• receive webhooks locally. Point Stripe or GitHub at https://<tunnel>/api/webhooks/....
• test OAuth sign-in with a provider that won’t redirect to localhost.

Share anything

flare tunnel shares any local port or URL, Flare app or not:

npx flare tunnel            # http://localhost:3000
npx flare tunnel 8787
npx flare tunnel http://localhost:5173

How it works

• The cloudflared binary. Flare uses cloudflared if it’s on your PATH. Otherwise it downloads Cloudflare’s official release once, from github.com/cloudflare/cloudflared, into ~/.flare/bin.
• flare dev --tunnel waits for the dev server to print its address, then opens the tunnel to it. Apps allow *.trycloudflare.com in server.allowedHosts (vite.config.ts), so Vite accepts the public hostname. Hot reload keeps working over the tunnel.
• flare start --tunnel opens the tunnel first, then starts wrangler dev with --local-upstream <tunnel host> --upstream-protocol https. That way the Worker sees the public origin, and sign-in works over the tunnel. While it runs, sign in through the public URL rather than localhost.
• Auth. Apps list *.trycloudflare.com in Better Auth’s allowed hosts (lib/auth.ts). This is safe in production: Cloudflare only routes hostnames a Worker actually serves, so a deployed app never receives a trycloudflare.com host.

Before you share

Anyone with the link can reach your local server while it runs:

• It uses your local database and your .dev.vars secrets.
• flare dev serves the Vite dev server, which exposes your source code. Prefer flare start --tunnel when the audience is outside your team.
• The security layer sees real visitor IPs through the tunnel, so bans and rate limits apply as they would in production.

Quick tunnels are for development and demos. They have no uptime guarantee, and Cloudflare limits them to 200 concurrent requests. For anything permanent, flare deploy.