Lesson 2 · An account-free public URL with cloudflared

In Lesson 1 the URL came from GitHub, so it only works inside a Codespace and an org owner can switch it off. A Cloudflare quick tunnel (a.k.a. TryCloudflare) is the opposite kind of tool: it makes an outbound connection from wherever your app runs to Cloudflare's edge, and Cloudflare publishes a random public URL pointing back through it. No inbound ports, no GitHub token, and — the part you asked for — no Cloudflare account. [Cloudflare Docs]

The one fact that matters cloudflared tunnel --url http://localhost:PORT with no login creates a throwaway tunnel and prints a fresh https://<random>.trycloudflare.com URL that anyone can open, no auth.

Why reach for this inside a Codespace?

Your org has disabled public Codespaces ports — this routes around that.
You want one lab guide whose steps are identical on a laptop, a VM, or a Codespace.
You want a URL not tied to your GitHub identity at all.

Do it now (≈ 2 minutes)

Install cloudflared in the Codespace (Ubuntu base — the direct .deb is the most reliable one-shot):

$ curl -L -o cloudflared.deb \
    https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-linux-amd64.deb
$ sudo dpkg -i cloudflared.deb
$ cloudflared --version          # confirm it's there

Start your web app on a port (throwaway example):
```
$ python3 -m http.server 8080
```

In a second terminal, open the tunnel:

$ cloudflared tunnel --url http://localhost:8080

Read the boxed line in the output — your public URL:

+----------------------------------------------------+
|  Your quick Tunnel has been created! Visit it at:  |
|  https://random-words-1234.trycloudflare.com       |
+----------------------------------------------------+

Open that URL in an incognito window. It loads with no login. Paste it into your guide.

Your win A public, auth-free URL to a Codespace web app created without ever signing in to Cloudflare — portable to any machine that can run one binary.

Make it paste-friendly for a guide

The command runs in the foreground and holds the terminal. For a lab guide, capture the URL without babysitting a second terminal:

$ cloudflared tunnel --url http://localhost:8080 \
    --logfile tunnel.log &            # run in background
$ grep -o 'https://.*trycloudflare.com' tunnel.log | head -1

Stop it later with kill %1 (or close the Codespace).

Free-tier limits to write into the guide

The URL is random and changes every run — trainees must copy the one printed in their session; you can't pre-print it.
~200 in-flight requests cap (excess gets HTTP 429). Fine for a lab, not a crowd-load test.
No Server-Sent Events (SSE) support on quick tunnels.
No SLA / uptime guarantee — it's explicitly for testing and development.
If a ~/.cloudflared/config.yaml exists, quick tunnels refuse to start — rename it.

Check yourself

What does a trainee need to sign in to before this URL works for them?

Compared with the Lesson 1 Codespaces URL, the quick-tunnel URL mainly differs because it…

I'm your teacher — ask me. Hitting a dpkg permission error, a config.yaml conflict, or wondering how to keep the tunnel alive when the Codespace idles? Ask in chat and we'll sort it before Lesson 3.

Read next (primary source): Cloudflare Docs — TryCloudflare (Quick Tunnels). The authoritative reference for the command, the URL, and every limit above.