--- title: Local Development description: Test Email Workers locally using Wrangler dev or the Cloudflare Vite plugin to simulate receiving, replying, and sending emails. image: https://developers.cloudflare.com/dev-products-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/email-routing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Local Development You can test the behavior of an Email Worker script in local development using Wrangler with [wrangler dev](https://developers.cloudflare.com/workers/wrangler/commands/general/#dev), or using the [Cloudflare Vite plugin ↗](https://developers.cloudflare.com/workers/vite-plugin/). This is the minimal wrangler configuration required to run an Email Worker locally: * [ wrangler.jsonc ](#tab-panel-6189) * [ wrangler.toml ](#tab-panel-6190) JSONC ``` { "send_email": [ { "name": "EMAIL" } ] } ``` TOML ``` [[send_email]] name = "EMAIL" ``` Note If you want to deploy your script you need to [enable Email Routing](https://developers.cloudflare.com/email-routing/get-started/enable-email-routing/) and have at least one verified [destination address](https://developers.cloudflare.com/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: TypeScript ``` 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: Terminal window ``` curl --request POST 'http://localhost:8787/cdn-cgi/handler/email' \ --url-query 'from=sender@example.com' \ --url-query 'to=recipient@example.com' \ --header 'Content-Type: application/json' \ --data-raw 'Received: from smtp.example.com (127.0.0.1) by cloudflare-email.com (unknown) id 4fwwffRXOpyR for ; Tue, 27 Aug 2024 15:50:20 +0000 From: "John" Reply-To: sender@example.com To: recipient@example.com 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: ``` { headers: [ { key: 'received', value: 'from smtp.example.com (127.0.0.1) by cloudflare-email.com (unknown) id 4fwwffRXOpyR for ; Tue, 27 Aug 2024 15:50:20 +0000' }, { key: 'from', value: '"John" ' }, { key: 'reply-to', value: 'sender@example.com' }, { key: 'to', value: 'recipient@example.com' }, { 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: 'sender@example.com', name: 'John' }, to: [ { address: 'recipient@example.com', name: '' } ], replyTo: [ { address: 'sender@example.com', 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: TypeScript ``` 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: 'sender@example.com' }); msg.setRecipient('recipient@example.com'); 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('sender@example.com', 'recipient@example.com', msg.asRaw()); await env.EMAIL.send(message); return Response.json({ ok: true }); } }; ``` Now when you run `npx wrangler dev`, go to [http://localhost:8787/ ↗](http://localhost:8787/) to trigger the `fetch()` handler and send the email. You will see the follow message in your terminal: ``` ⎔ 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?= To: Message-ID: <2s95plkazox@example.com> 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](https://developers.cloudflare.com/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: TypeScript ``` 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: 'sender@example.com' }); 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('sender@example.com', message.from, msg.asRaw()); await message.reply(replyMessage); await message.forward("recipient@example.com"); }, }; ``` 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: ``` ⎔ 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: recipient@example.com ``` ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/email-routing/","name":"Email Routing"}},{"@type":"ListItem","position":3,"item":{"@id":"/email-routing/email-workers/","name":"Email Workers"}},{"@type":"ListItem","position":4,"item":{"@id":"/email-routing/email-workers/local-development/","name":"Local Development"}}]} ```