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postal-mime

postal-mime is an email parsing library that runs in browser environments (including Web Workers) and serverless functions (like Cloudflare Email Workers). It takes in a raw email message (RFC822 format) and outputs a structured object containing headers, recipients, attachments, and more.

Features​

  • Zero Dependencies - No external dependencies, keeping your bundle size minimal
  • Universal Compatibility - Works in browsers, Web Workers, Node.js, and serverless environments like Cloudflare Workers
  • TypeScript Support - Fully typed with comprehensive type definitions
  • RFC Compliant - Follows RFC 2822/5322 email standards
  • Complex MIME Handling - Supports multipart messages, nested parts, and attachments
  • Security Built-in - Protection against deeply nested messages and oversized headers

Quick Example​

import PostalMime from 'postal-mime';

const email = await PostalMime.parse(`Subject: Hello World
Content-Type: text/html; charset=utf-8

<p>Welcome to postal-mime!</p>`);

console.log(email.subject); // "Hello World"
console.log(email.html);    // "<p>Welcome to postal-mime!</p>"

Installation​

npm install postal-mime

Requirements​

  • Modern browser with ES6 support, or
  • Node.js 14.0+, or
  • Cloudflare Workers / Deno / Bun

How It Works​

Next Steps​

postal-mime is developed by the makers of EmailEngine - a self-hosted email gateway that provides a REST API for IMAP and SMTP servers and sends webhooks whenever something changes in registered accounts.