Add tutorials for cloudflare workers with wrangler

examples/tutorials/cloudflare_workers_wrangler.md

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+---
+last_modified: 2026-04-18
+title: "Deploying Deno to Cloudflare Workers with Wrangler"
+description: "Learn how to build and deploy a Deno application to Cloudflare Workers using Wrangler"
+url: /examples/cloudflare_workers_wrangler_tutorial/
+---
+
+Cloudflare Workers allows you to run JavaScript on Cloudflare's edge network.
+
+This is a short How To guide on deploying a Deno function to Cloudflare Workers.
+If you are looking to build a standard Deno web server instead, check out the
+[HTTP Server tutorial](/examples/http_server/). If you want to use third-party
+tool `denoflare`, refer to
+[Cloudflare Workers tutorial](/examples/cloudflare_workers_tutorial/).
+
+Note: You would only be able to deploy
+[Module Workers](https://developers.cloudflare.com/workers/learning/migrating-to-module-workers/)
+instead of web servers or apps.
+
+## Setup wrangler
+
+First, initialize your project and add Cloudflare's `wrangler` CLI as an npm
+dependency. Deno's native npm support makes this seamless.
+
+```shell
+deno add npm:wrangler
+```
+
+Next, configure your Cloudflare project by creating a `wrangler.json` file in
+the root directory. We'll set the entry point to a `src/mod.ts` file we will
+create later.
+
+```json
+{
+  "$schema": "https://www.unpkg.com/wrangler@4.38.0/config-schema.json",
+  "name": "deno-wrangler",
+  "main": "src/mod.ts",
+  "compatibility_date": "2026-04-18",
+  "observability": {
+    "enabled": true
+  }
+}
+```
+
+Update your `deno.json` file to include helpful tasks for local development and
+deployment. We can invoke Wrangler directly through Deno.
+
+```json
+{
+  "tasks": {
+    "deploy": "deno --allow-env --allow-run wrangler deploy",
+    "dev": "deno wrangler dev",
+    "start": "deno wrangler dev",
+    "cf-typegen": "deno wrangler types"
+  }
+}
+```
+
+Run the type generation task to create Cloudflare environment types so your
+TypeScript compiler understands the Cloudflare context.
+
+```shell
+deno task cf-typegen
+```
+
+## Create your function
+
+Now, create your worker script in `src/mod.ts`. It needs to export an object
+containing a `fetch` handler to satisfy the Cloudflare Module Worker API.
+
+```typescript
+export default {
+  async fetch(req) {
+    return new Response("Hello World");
+  },
+} satisfies ExportHandler<Env>;
+```
+
+## Setup build
+
+Because Cloudflare Workers runs raw JavaScript and needs standard module
+resolution, we must bundle our Deno code (and resolve Deno-specific imports)
+before deploying when we depend on external libraries. We will use `esbuild` for
+this. For a deeper dive into how this works, see the
+[esbuild tutorial](https://www.google.com/search?q=/examples/esbuild/).
+
+Add `esbuild` and the official Deno esbuild plugin to your dependencies:
+
+```shell
+deno add npm:esbuild jsr:@deno/esbuild-plugin
+```
+
+Create a `build.ts` script in your root directory. This script will bundle your
+`src/mod.ts` file into a single JavaScript file at `dist/server.js`.
+
+```typescript
+import * as esbuild from "esbuild";
+import { denoPlugin } from "@deno/esbuild-plugin";
+
+await esbuild.build({
+  entryPoints: ["./src/mod.ts"],
+  outfile: "./dist/server.js",
+  format: "esm",
+  bundle: true,
+  minify: true,
+  treeShaking: true,
+  plugins: [
+    denoPlugin(),
+  ],
+});
+
+await esbuild.stop();
+```
+
+Finally, add a build task to your `deno.json` (e.g.,
+`"build": "deno run -A build.ts"`)
+
+```json
+{
+  "tasks": {
+    "build": "deno run -REW --allow-run build.ts"
+  }
+}
+```
+
+and update your `wrangler.json` to instruct Wrangler to execute this build step
+prior to deployment. Make sure your `main` field points to the bundled output
+(`dist/server.js`).
+
+```json
+{
+  "$schema": "https://www.unpkg.com/wrangler@4.38.0/config-schema.json",
+  "name": "deno-wrangler",
+  "main": "dist/server.js",
+  "compatibility_date": "2026-04-18",
+  "observability": {
+    "enabled": true
+  },
+  "build": {
+    "command": "deno task build"
+  }
+}
+```
+
+## Deploy
+
+With everything configured, deploying to Cloudflare's edge network is just one
+command away.
+
+Run the deploy task we set up in our deno.json:
+
+```shell
+deno task deploy
+```
+
+Wrangler will automatically run your build.ts script to bundle the application,
+and then safely publish the resulting dist/server.js file to Cloudflare Workers.
+Once finished, Wrangler will output the live URL where your worker is hosted.