---
title: Threaded replies now possible in Email Workers
description: You can now use Email Workers to send multiple replies to the same email thread.
image: https://developers.cloudflare.com/changelog-preview.png
---

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## Threaded replies now possible in Email Workers

Mar 12, 2025 

[ Email Service ](https://developers.cloudflare.com/email-service/) 

We’re removing some of the restrictions in Email Routing so that AI Agents and task automation can better handle email workflows, including how Workers can [reply](https://developers.cloudflare.com/email-service/api/route-emails/email-handler/#reply-to-emails) to incoming emails.

It's now possible to keep a threaded email conversation with an [Email Worker](https://developers.cloudflare.com/email-service/api/route-emails/email-handler/) script as long as:

* The incoming email has to have valid [DMARC ↗](https://www.cloudflare.com/learning/dns/dns-records/dns-dmarc-record/).
* The email can only be replied to once in the same `EmailMessage` event.
* The recipient in the reply must match the incoming sender.
* The outgoing sender domain must match the same domain that received the email.
* Every time an email passes through Email Routing or another MTA, an entry is added to the `References` list. We stop accepting replies to emails with more than 100 `References` entries to prevent abuse or accidental loops.

Here's an example of a Worker responding to Emails using a Workers AI model:

AI model responding to emails

```
import PostalMime from "postal-mime";import { createMimeMessage } from "mimetext";import { EmailMessage } from "cloudflare:email";
export default {  async email(message, env, ctx) {    const email = await PostalMime.parse(message.raw);    const res = await env.AI.run("@cf/meta/llama-2-7b-chat-fp16", {      messages: [        {          role: "user",          content: email.text ?? "",        },      ],    });
    // message-id is generated by mimetext    const response = createMimeMessage();    response.setHeader("In-Reply-To", message.headers.get("Message-ID")!);    response.setSender("agent@example.com");    response.setRecipient(message.from);    response.setSubject("Llama response");    response.addMessage({      contentType: "text/plain",      data:        res instanceof ReadableStream          ? await new Response(res).text()          : res.response!,    });
    const replyMessage = new EmailMessage(      "<email>",      message.from,      response.asRaw(),    );    await message.reply(replyMessage);  },} satisfies ExportedHandler<Env>;
```

See [Reply to emails from Workers](https://developers.cloudflare.com/email-service/api/route-emails/email-handler/#reply-to-emails) for more information.

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```