Quick start

Create a temporary public preview without a Cloudflare account or API token.

1. Check prerequisites

Install Node.js 22.14+ and cloudflared. Then verify both are available:

node --version
cloudflared --version

If cloudflared is installed outside your PATH, set FLASH_TUNNEL_CLOUDFLARED to its executable path.

2. Run inside your project

Open a terminal in a project with a dev script and run:

npx flash-tunnel --mode quick

flash-tunnel detects the startup command and local port, starts the server, and waits until a public https://…trycloudflare.com URL responds. Copy that URL and share it. Keep the terminal running for as long as you need the preview.

Already running your server?

Connect to it directly:

npx flash-tunnel --mode quick --url http://127.0.0.1:5173 --attach

An attached server remains yours to stop. flash-tunnel only stops child processes it started.

3. Stop the preview

Press Ctrl+C once and allow cleanup to finish. In an interactive terminal, c copies the URL, o opens it, and q stops the preview with cleanup.

The public URL is temporary. A later quick-mode run receives a new address.

Install for repeated use

Project dependency

pnpm add -D flash-tunnel
pnpm exec flash-tunnel --mode quick

Global install

npm install -g flash-tunnel
flash-tunnel --mode quick

A project dependency lets you pin the version with your project's lockfile.

Optional setup

npx flash-tunnel doctor
npx flash-tunnel init

doctor checks the environment and effective configuration. It may report missing credentials when the effective mode is named; quick previews do not need those credentials. init creates an optional flash-tunnel.ts file.

Where next?

• Custom domains: use your Cloudflare domain.
• Local servers: choose scripts, static files, or an existing server.
• Troubleshooting: resolve host checks, ports, or startup failures.