Email Workers local development

src/content/changelog/email-routing/2025-04-08-local-development.mdx

@@ -0,0 +1,77 @@
+---
+title: Local development support for Email Workers
+description: Developers can now use wrangler to do local development for Email Workers.
+date: 2025-04-08T15:00:00Z
+---
+
+Email Workers enables developers to programmatically take action on anything that hits their email inbox. If you're building with Email Workers, you can now test the behavior of an Email Worker script, receiving, replying and sending emails in your local environment using `wrangler dev`.
+
+Below is an example that shows you how you can receive messages using the `email()` handler and parse them using [postal-mime](https://www.npmjs.com/package/postal-mime):
+
+```ts
+import * as PostalMime from 'postal-mime';
+
+export default {
+	async email(message, env, ctx) {
+		const parser = new PostalMime.default();
+		const rawEmail = new Response(message.raw);
+		const email = await parser.parse(await rawEmail.arrayBuffer());
+		console.log(email);
+	},
+};
+
+Now when you run `npx wrangler dev`, wrangler will expose a local `/cdn-cgi/handler/email` endpoint that you can `POST` email messages to and trigger your Worker's `email()` handler:
+
+```bash
+curl -X POST 'http://localhost:8787/cdn-cgi/handler/email' \
+  --url-query '[email protected]' \
+  --url-query '[email protected]' \
+  --header 'Content-Type: application/json' \
+  --data-raw 'Received: from smtp.example.com (127.0.0.1)
+        by cloudflare-email.com (unknown) id 4fwwffRXOpyR
+        for <[email protected]>; Tue, 27 Aug 2024 15:50:20 +0000
+From: "John" <[email protected]>
+Reply-To: [email protected]
+To: [email protected]
+Subject: Testing Email Workers Local Dev
+Content-Type: text/html; charset="windows-1252"
+X-Mailer: Curl
+Date: Tue, 27 Aug 2024 08:49:44 -0700
+Message-ID: <6114391943504294873000@ZSH-GHOSTTY>
+
+Hi there'
+```
+
+This is what you get in the console:
+
+```json
+{
+  headers: [
+    {
+      key: 'received',
+      value: 'from smtp.example.com (127.0.0.1) by cloudflare-email.com (unknown) id 4fwwffRXOpyR for <[email protected]>; Tue, 27 Aug 2024 15:50:20 +0000'
+    },
+    { key: 'from', value: '"John" <[email protected]>' },
+    { key: 'reply-to', value: '[email protected]' },
+    { key: 'to', value: '[email protected]' },
+    { key: 'subject', value: 'Testing Email Workers Local Dev' },
+    { key: 'content-type', value: 'text/html; charset="windows-1252"' },
+    { key: 'x-mailer', value: 'Curl' },
+    { key: 'date', value: 'Tue, 27 Aug 2024 08:49:44 -0700' },
+    {
+      key: 'message-id',
+      value: '<6114391943504294873000@ZSH-GHOSTTY>'
+    }
+  ],
+  from: { address: '[email protected]', name: 'John' },
+  to: [ { address: '[email protected]', name: '' } ],
+  replyTo: [ { address: '[email protected]', name: '' } ],
+  subject: 'Testing Email Workers Local Dev',
+  messageId: '<6114391943504294873000@ZSH-GHOSTTY>',
+  date: '2024-08-27T15:49:44.000Z',
+  html: 'Hi there\n',
+  attachments: []
+}
+```
+
+Local development is a critical part of the development flow, and also works for sending, replying and forwarding emails. See [our documentation](/email-routing/email-workers/local-development/) for more information.

src/content/docs/email-routing/email-workers/demos.mdx

@@ -2,7 +2,7 @@
 pcx_content_type: navigation
 title: Demos
 sidebar:
-  order: 6
+  order: 7
 
 ---
 
@@ -14,4 +14,4 @@ Learn how you can use Email Workers within your existing architecture.
 
 Explore the following <GlossaryTooltip term="demo application">demo applications</GlossaryTooltip> for Email Workers.
 
-<ExternalResources type="apps" products={["Email Workers"]} />
+<ExternalResources type="apps" products={["Email Workers"]} />

src/content/docs/email-routing/email-workers/local-development.mdx

@@ -0,0 +1,206 @@
+---
+title: Local Development
+sidebar:
+  order: 6
+  badge: Beta
+
+---
+
+import { Render, Type, MetaInfo, WranglerConfig } from "~/components";
+
+You can test the behavior of an Email Worker script in local development using [wrangler dev](/workers/wrangler/commands/#dev).
+
+This is the minimal wrangler configuration required to run an Email Worker locally:
+
+<WranglerConfig>
+
+```jsonc
+{
+  "send_email": [
+    {
+      "name": "EMAIL"
+    }
+  ]
+}
+```
+
+</WranglerConfig>
+
+:::note
+
+If you want to deploy your script you need to [enable Email Routing](/email-routing/get-started/enable-email-routing/) and have at least one verified [destination address](/email-routing/setup/email-routing-addresses/#destination-addresses).
+
+:::
+
+You can now test receiving, replying, and sending emails in your local environment.
+
+## Receive an email
+
+Consider this example Email Worker script that uses the open source [`postal-mime`](https://www.npmjs.com/package/postal-mime) email parser:
+
+```ts
+import * as PostalMime from 'postal-mime';
+
+export default {
+	async email(message, env, ctx) {
+		const parser = new PostalMime.default();
+		const rawEmail = new Response(message.raw);
+		const email = await parser.parse(await rawEmail.arrayBuffer());
+		console.log(email);
+	},
+};
+```
+
+Now when you run `npx wrangler dev`, wrangler will expose a local `/cdn-cgi/handler/email` endpoint that you can `POST` email messages to and trigger your Worker's `email()` handler:
+
+```bash
+curl --request POST 'http://localhost:8787/cdn-cgi/handler/email' \
+  --url-query '[email protected]' \
+  --url-query '[email protected]' \
+  --header 'Content-Type: application/json' \
+  --data-raw 'Received: from smtp.example.com (127.0.0.1)
+        by cloudflare-email.com (unknown) id 4fwwffRXOpyR
+        for <[email protected]>; Tue, 27 Aug 2024 15:50:20 +0000
+From: "John" <[email protected]>
+Reply-To: [email protected]
+To: [email protected]
+Subject: Testing Email Workers Local Dev
+Content-Type: text/html; charset="windows-1252"
+X-Mailer: Curl
+Date: Tue, 27 Aug 2024 08:49:44 -0700
+Message-ID: <6114391943504294873000@ZSH-GHOSTTY>
+
+Hi there'
+```
+
+This is what you get in the console:
+
+```json
+{
+  headers: [
+    {
+      key: 'received',
+      value: 'from smtp.example.com (127.0.0.1) by cloudflare-email.com (unknown) id 4fwwffRXOpyR for <[email protected]>; Tue, 27 Aug 2024 15:50:20 +0000'
+    },
+    { key: 'from', value: '"John" <[email protected]>' },
+    { key: 'reply-to', value: '[email protected]' },
+    { key: 'to', value: '[email protected]' },
+    { key: 'subject', value: 'Testing Email Workers Local Dev' },
+    { key: 'content-type', value: 'text/html; charset="windows-1252"' },
+    { key: 'x-mailer', value: 'Curl' },
+    { key: 'date', value: 'Tue, 27 Aug 2024 08:49:44 -0700' },
+    {
+      key: 'message-id',
+      value: '<6114391943504294873000@ZSH-GHOSTTY>'
+    }
+  ],
+  from: { address: '[email protected]', name: 'John' },
+  to: [ { address: '[email protected]', name: '' } ],
+  replyTo: [ { address: '[email protected]', name: '' } ],
+  subject: 'Testing Email Workers Local Dev',
+  messageId: '<6114391943504294873000@ZSH-GHOSTTY>',
+  date: '2024-08-27T15:49:44.000Z',
+  html: 'Hi there\n',
+  attachments: []
+}
+```
+
+## Send an email
+
+Wrangler can also simulate sending emails locally. Consider this example Email Worker script that uses the [`mimetext`](https://www.npmjs.com/package/mimetext) npm package:
+
+```ts
+import { EmailMessage } from "cloudflare:email";
+import { createMimeMessage } from 'mimetext';
+
+export default {
+	async fetch(request, env, ctx) {
+		const msg = createMimeMessage();
+		msg.setSender({ name: 'Sending email test', addr: '[email protected]' });
+		msg.setRecipient('[email protected]');
+		msg.setSubject('An email generated in a worker');
+		msg.addMessage({
+			contentType: 'text/plain',
+			data: `Congratulations, you just sent an email from a worker.`,
+		});
+
+		var message = new EmailMessage('[email protected]', '[email protected]', msg.asRaw());
+		await env.EMAIL.send(message);
+		return Response.json({ ok: true });
+	}
+};
+```
+
+Now when you run `npx wrangler dev`, go to http://localhost:8787/ to trigger the `fetch()` handler and send the email. You will see the follow message in your terminal:
+
+```txt
+⎔ Starting local server...
+[wrangler:inf] Ready on http://localhost:8787
+[wrangler:inf] GET / 200 OK (19ms)
+[wrangler:inf] send_email binding called with the following message:
+  /var/folders/33/pn86qymd0w50htvsjp93rys40000gn/T/miniflare-f9be031ff417b2e67f2ac4cf94cb1b40/files/email/33e0a255-a7df-4f40-b712-0291806ed2b3.eml
+```
+
+Wrangler simulated `env.EMAIL.send()` by writing the email to a local file in [eml](https://datatracker.ietf.org/doc/html/rfc5322) format. The file contains the raw email message:
+
+```
+Date: Fri, 04 Apr 2025 12:27:08 +0000
+From: =?utf-8?B?U2VuZGluZyBlbWFpbCB0ZXN0?= <[email protected]>
+To: <[email protected]>
+Message-ID: <[email protected]>
+Subject: =?utf-8?B?QW4gZW1haWwgZ2VuZXJhdGVkIGluIGEgd29ya2Vy?=
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 7bit
+
+Congratulations, you just sent an email from a worker.
+```
+
+## Reply to and forward messages
+
+Likewise, [`EmailMessage`](/email-routing/email-workers/runtime-api/#emailmessage-definition)'s `forward()` and `reply()` methods are also simulated locally. Consider this Worker that receives an email, parses it, replies to the sender, and forwards the original message to one your verified recipient addresses:
+
+```ts
+import * as PostalMime from 'postal-mime';
+import { createMimeMessage } from 'mimetext';
+import { EmailMessage } from 'cloudflare:email';
+
+export default {
+	async email(message, env: any, ctx: any) {
+		// parses incoming message
+		const parser = new PostalMime.default();
+		const rawEmail = new Response(message.raw);
+		const email = await parser.parse(await rawEmail.arrayBuffer());
+
+		// creates some ticket
+		// const ticket = await createTicket(email);
+
+		// creates reply message
+		const msg = createMimeMessage();
+		msg.setSender({ name: 'Thank you for your contact', addr: '[email protected]' });
+		msg.setRecipient(message.from);
+		msg.setHeader('In-Reply-To', message.headers.get('Message-ID'));
+		msg.setSubject('An email generated in a worker');
+		msg.addMessage({
+			contentType: 'text/plain',
+			data: `This is an automated reply. We received you email with the subject "${email.subject}", and will handle it as soon as possible.`,
+		});
+
+		const replyMessage = new EmailMessage('[email protected]', message.from, msg.asRaw());
+
+		await message.reply(replyMessage);
+		await message.forward("[email protected]");
+	},
+};
+```
+
+Run `npx wrangler dev` and use curl to `POST` the same message from the [Receive an email](#receive-an-email) example. Your terminal will show you where to find the replied message in your local disk and to whom the email was forwarded:
+
+```txt
+⎔ Starting local server...
+[wrangler:inf] Ready on http://localhost:8787
+[wrangler:inf] Email handler replied to sender with the following message:
+  /var/folders/33/pn86qymd0w50htvsjp93rys40000gn/T/miniflare-381a79d7efa4e991607b30a079f6b17d/files/email/a1db7ebb-ccb4-45ef-b315-df49c6d820c0.eml
+[wrangler:inf] Email handler forwarded message with
+  rcptTo: [email protected]
+```

src/content/docs/email-routing/email-workers/runtime-api.mdx

@@ -17,8 +17,8 @@ An `EmailEvent` is the event type to programmatically process your emails with a
 `EmailEvent` can be handled in Workers functions written using the Service Worker syntax by attaching to the `email` event with `addEventListener`:
 
 ```js
-addEventListener("email", (event) => {
-  event.message.forward("<YOUR_EMAIL>");
+addEventListener("email", async (event) => {
+  await event.message.forward("<YOUR_EMAIL>");
 });
 ```
 
@@ -41,7 +41,7 @@ addEventListener("email", (event) => {
 ```js
 export default {
   async email(message, env, ctx) {
-    message.forward("<YOUR_EMAIL>");
+    await message.forward("<YOUR_EMAIL>");
   },
 };
 ```
@@ -118,4 +118,3 @@ export default {
 
   * Reply to the sender of this email message with a new EmailMessage object.
   * When the promise resolves, the message is confirmed to be replied.
-

src/content/glossary/fundamentals.yaml

@@ -112,7 +112,7 @@ entries:
   - term: protocol
     general_definition: |-
       a protocol is a set of rules governing the exchange or transmission of data between devices.
-  
+
   - term: proxy server
     general_definition: |-
       the server that sits between the origin server and the client. Cloudflare is a proxy server for example.

src/content/learning-paths/china-network-overview.json

@@ -2,7 +2,7 @@
 	"title": "Introduction to the China Network",
 	"path": "/learning-paths/china-network-overview/series/china-network-main-features-1/",
 	"priority": 1,
-	"description":"Watch to learn how Cloudflare's China Network can help you improve performance, compliance, and connectivity for your users in mainland China.",
+	"description": "Watch to learn how Cloudflare's China Network can help you improve performance, compliance, and connectivity for your users in mainland China.",
 	"products": ["China Network"],
 	"product_group": "Application performance",
 	"additional_groups": ["Application security"],

src/content/learning-paths/durable-objects-course.json

@@ -2,7 +2,7 @@
 	"title": "Introduction to Durable Objects",
 	"path": "/learning-paths/durable-objects-course/series/introduction-to-series-1/",
 	"priority": 2,
-	"description":"Dive into a hands-on Durable Objects project and learn how to build stateful apps using serverless architecture",
+	"description": "Dive into a hands-on Durable Objects project and learn how to build stateful apps using serverless architecture",
 	"products": ["Durable Objects", "Workers"],
 	"product_group": "Developer platform",
 	"video": true

src/content/release-notes/api-deprecations.yaml

@@ -5,7 +5,6 @@ productLink: "/fundamentals/"
 productArea: Core platform
 productAreaLink: /fundamentals/reference/changelog/platform/
 entries:
-
   - publish_date: "2025-03-20"
     title: "Cloudflare Radar: Attack top industry and vertical endpoints"
     description: |-