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Simple HTTP server

In this tutorial, let's build a HTTP server that responds to all incoming HTTP requests with Hello, world! and a 200 OK HTTP status. We will be using the Deno Deploy playground to deploy and edit this script.

Step 1: Write the HTTP server script​

A simple HTTP server can be written with a single line of code in Deno using Deno.serve:

One-line HTTP server
Deno.serve(() => new Response("Hello, world!"));

While this type of server is useful for getting started, Deno.serve is capable of supporting more advanced usage as well (API reference docs). Below is an example of a more complex server that takes advantage of other API features.

More complex Hello World server
Deno.serve({
  onListen: ({ port }) => {
    console.log("Deno server listening on *:", port);
  },
}, (req: Request, conn: Deno.ServeHandlerInfo) => {
  // Get information about the incoming request
  const method = req.method;
  const ip = conn.remoteAddr.hostname;
  console.log(`${ip} just made an HTTP ${method} request.`);

  // Return a web standard Response object
  return new Response("Hello, world!");
});

Step 2: Deploy script to Deno Deploy​

  1. Create a new playground project by visiting your Deno dashboard, and clicking the New Playground button.
  2. On the next screen, copy the code above (either the short or the longer example) into the editor on the left side of the screen.
  3. Press the Save & Deploy button on the right side of the top toolbar (or press Ctrl+S).

You can preview the result on the right side of the playground editor, in the preview pane.

You will see that if you change the script (for example Hello, World! -> Hello, Galaxy!) and then re-deploy, the preview will automatically update. The URL shown at the top of the preview pane can be used to visit the deployed page from anywhere.

Even in the playground editor, scripts are deployed worldwide across our entire global network. This guarantees fast and reliable performance, no matter the location of your users.