EmailSender

Learn how to configure Cloudflare Email Service send_email bindings for Workers using Alchemy.

The Cloudflare Email Service Workers API lets your Worker send outbound email through a native send_email binding.

Use EmailSender() inside a Worker’s bindings block when you want first-class, type-safe email sending from env.

Minimal Example

Create a Worker with an email binding:

import { EmailSender, Worker } from "alchemy/cloudflare";

const worker = await Worker("mailer", {
  name: "mailer",
  entrypoint: "./src/worker.ts",
  bindings: {
    EMAIL: EmailSender(),
  },
});

Worker Runtime Usage

Send a plain-text email from your Worker:

interface Env {
  EMAIL: SendEmail;
}

export default {
  async fetch(_request: Request, env: Env) {
    await env.EMAIL.send({
      from: "noreply@example.com",
      to: "hello@example.com",
      subject: "Hello",
      text: "Sent from Cloudflare Email Service.",
    });

    return new Response("sent");
  },
};

HTML Email

Send an HTML email with a plain-text fallback:

interface Env {
  EMAIL: SendEmail;
}

export default {
  async fetch(_request: Request, env: Env) {
    await env.EMAIL.send({
      from: "noreply@example.com",
      to: "hello@example.com",
      subject: "Welcome",
      html: "<h1>Welcome</h1><p>Your account is ready.</p>",
      text: "Welcome. Your account is ready.",
    });

    return new Response("sent");
  },
};

Restrict Allowed Senders

Lock the binding down to one or more sender addresses:

import { EmailSender, Worker } from "alchemy/cloudflare";

const worker = await Worker("mailer", {
  name: "mailer",
  entrypoint: "./src/worker.ts",
  bindings: {
    EMAIL: EmailSender({
      allowedSenderAddresses: ["noreply@example.com"],
    }),
  },
});

Restrict Destinations

Use destinationAddress to pin delivery to a single address, or allowedDestinationAddresses to allow a list of addresses:

import { EmailSender, Worker } from "alchemy/cloudflare";

const worker = await Worker("mailer", {
  name: "mailer",
  entrypoint: "./src/worker.ts",
  bindings: {
    EMAIL: EmailSender({
      allowedDestinationAddresses: [
        "ops@example.com",
        "support@example.com",
      ],
    }),
  },
});

destinationAddress and allowedDestinationAddresses are mutually exclusive.

Local Development With Remote Email Sending

Set dev.remote to true to keep the Worker running locally while the email binding sends through Cloudflare:

import { EmailSender, Worker } from "alchemy/cloudflare";

const worker = await Worker("mailer", {
  name: "mailer",
  entrypoint: "./src/worker.ts",
  bindings: {
    EMAIL: EmailSender({
      allowedSenderAddresses: ["noreply@example.com"],
      dev: { remote: true },
    }),
  },
});

Properties

Input Properties

destinationAddress (string, optional): Restrict all sends to a single destination address
allowedDestinationAddresses (string[], optional): Restrict sends to a fixed allowlist of destination addresses
allowedSenderAddresses (string[], optional): Restrict sends to a fixed allowlist of sender addresses
dev.remote (boolean, optional): Use Cloudflare’s remote binding while developing locally