Build your own `What's My Ip` service

If you’ve ever struggled to find the public IP address of a server, especially when you only have CLI access, you’re not alone. There are services out there like ifconfig.me, ipify.org, and others. But personally, the problem I always face is simple: I forget their URLs when I need them, I always need to google the correct curl command.

The good news is, you don’t have to rely on third party sites. You can build your own lightweight public IP echo service using Cloudflare Workers for free.

Log in to your Cloudflare account.
Go to Compute (Workers) -> Workers & Pages -> Create.
Under “Start with Hello World!”, click Get Started.
Give your worker a name and click Deploy.
Once your worker finished deploying, Go to your worker’s page (either from the deploy success screen or via Compute (Workers) -> Workers & Pages).
Click Edit Code, and replace the default sample with the following:

export default {
  async fetch(request) {
    return new Response(
      request.headers.get("cf-connecting-ip") + "\n",
      { headers: { "content-type": "text/plain" } }
    );
  }
}

The above code listens for requests to your worker URL, extract the client’s IP from the cf-connecting-ip header which is set by cloudflare and returns it as plain text with a new line. If you are not using cloudflare workers which are usually behind cloudflares Edge (proxy), you can try x-forwarded-for instead of cf-connecting-ip if you are hosing your serverless function behind another revers proxy such as haproxy or nginx. x-forwarded-for can contain multiple IPs separated by comma, depending on how many proxies the request went through.

Then Click Deploy to save your changes.
At this point, you can visit your worker’s default URL or run:

curl https://worker_name.username.workers.dev

That works, but it doesn’t solve my main issue: I always forget the URL.
To fix this you can assign a custom subdomain you’ll remember.
Go to your worker’s Settings -> Domain & Routes.
Click + Add -> Custom Domain.
Enter an easy to remember domain (for me it was ip.tadiosabebe.com).
The domain you used in the above step must already be managed in your Cloudflare account (which is free once you have a domain).

That’s it! Now you have your own personal “What’s My IP” service.

Try it for your self. It works in any browser: https://ip.tadiosabebe.com Or from the CLI:

curl https://ip.tadiosabebe.com