Worker Mailer

English | 简体中文

Worker Mailer is an SMTP client that runs on Cloudflare Workers. It leverages Cloudflare TCP Sockets and doesn't rely on any other dependencies.

Features

• 🚀 Completely built on the Cloudflare Workers runtime with no other dependencies
• 📝 Full TypeScript type support
• 📧 Supports sending plain text and HTML emails
• 🔒 Supports multiple SMTP authentication methods: plain, login, and CRAM-MD5
• 👥 Rich recipient options: TO, CC, BCC, and Reply-To
• 🎨 Custom email headers support

Table of Contents

• Installation
• Quick Start
• API Reference
• Limitations
• Contributing
• License

Installation

npm i worker-mailer

Quick Start

1. Configure your wrangler.toml:

compatibility_flags = ["nodejs_compat"]
# or compatibility_flags = ["nodejs_compat_v2"]

2. Use in your code:

import { WorkerMailer } from 'worker-mailer'

// Connect to SMTP server
const mailer = await WorkerMailer.connect({
  credentials: {
    username: '[email protected]',
    password: 'password',
  },
  authType: 'plain',
  host: 'smtp.acme.com',
  port: 587,
  secure: true,
})

// Send email
await mailer.send({
  from: { name: 'Bob', email: '[email protected]' },
  to: { name: 'Alice', email: '[email protected]' },
  subject: 'Hello from Worker Mailer',
  text: 'This is a plain text message',
  html: '<h1>Hello</h1><p>This is an HTML message</p>'
})

API Reference

WorkerMailer.connect(options)

Creates a new SMTP connection.

type WorkerMailerOptions = {
  host: string;              // SMTP server hostname
  port: number;              // SMTP server port (usually 587 or 465)
  secure?: boolean;          // Use TLS (default: false)
  credentials?: {            // SMTP authentication credentials
    username: string;
    password: string;
  };
  authType?: 'plain' | 'login' | 'cram-md5' | Array<'plain' | 'login' | 'cram-md5'>;
  logLevel?: LogLevel;       // Logging level (default: LogLevel.INFO)
  socketTimeoutMs?: number;  // Socket timeout in milliseconds
  responseTimeoutMs?: number;// Server response timeout in milliseconds
}

mailer.send(options)

Sends an email.

type EmailOptions = {
  from: string | {          // Sender's email
    name?: string;
    email: string;
  };
  to: string | string[] | { // Recipients (TO)
    name?: string;
    email: string;
  } | Array<{ name?: string; email: string }>;
  reply?: string | {        // Reply-To address
    name?: string;
    email: string;
  };
  cc?: string | string[] | { // Carbon Copy recipients
    name?: string;
    email: string;
  } | Array<{ name?: string; email: string }>;
  bcc?: string | string[] | { // Blind Carbon Copy recipients
    name?: string;
    email: string;
  } | Array<{ name?: string; email: string }>;
  subject: string;          // Email subject
  text?: string;            // Plain text content
  html?: string;            // HTML content
  headers?: Record<string, string>; // Custom email headers
}

Static Method: WorkerMailer.send()

Send a one-off email without maintaining the connection.

await WorkerMailer.send(
  {
    // WorkerMailerOptions
    host: 'smtp.acme.com',
    port: 587,
    credentials: {
      username: 'user',
      password: 'pass'
    }
  },
  {
    // EmailOptions
    from: '[email protected]',
    to: '[email protected]',
    subject: 'Test',
    text: 'Hello'
  }
)

Limitations

• Port Restrictions: Cloudflare Workers cannot make outbound connections on port 25. You won't be able to send emails via port 25, but common ports like 587 and 465 are supported.
• Connection Limits: Each Worker instance has a limit on the number of concurrent TCP connections. Make sure to properly close connections when done.

Contributing

We welcome your contributions! If you encounter any issues or have suggestions while using this library, feel free to open an issue on our GitHub repository.

License

This project is licensed under the MIT License.