📧 Email Generator Microservice

A lightweight, self-hostable service for rendering HTML emails with React Email.

• Hassle-free & maintenance-free – runs entirely on the free tier of Cloudflare Workers.
• Simple to use – perfect for login codes, registration flows, and other transactional emails.
• Flexible – develop locally with a Bun server, then deploy serverlessly with zero configuration.
• Clean separation – does not pollute your project with react or react-email imports or dependencies.

Whether you need a quick drop-in solution or a fully open-source foundation for your project, this microservice makes email generation easy and reliable.

Quick Links

• code - https://github.com/adaptive-shield-matrix/email-generator
• npm - https://www.npmjs.com/package/@adaptive-sm/email-generator
• react email docs - https://react.email/docs/getting-started/manual-setup

Features

• Renders HTML and plain text email templates.
• Supports internationalization (English and German).
• Validates input using Valibot schemas.
• Includes server timing headers for performance monitoring.
• Endpoints: /renderEmailTemplate/signUpV1, /renderEmailTemplate/signInV1, and /renderEmailTemplate/orgInvitationV1.

Templates

Name	Image
signUpV1: Sign-up registration email
signInV1: Sign-in login email
orgInvitationV1: Organization invitation email

Prerequisites

• Node.js (for package management) or Bun.
• Cloudflare account (for Workers deployment).

Local Development

1. Clone the repository.
2. Install dependencies:

   bun install
   

With Bun Server

• Start the development server:

  bun run start
  

  The server runs on http://localhost:3055 (port configurable via src/server/serverPortBun.ts).

• For React Email preview (optional):

  bun run dev
  

  This starts the preview server at http://localhost:3055 for template development.

With Cloudflare Workers

• Start the local Worker development server:

  bun run dev:worker
  

  The Worker runs on http://localhost:8787 (default Wrangler port).

• To test endpoints, send POST requests to:

  • http://localhost:8787/renderEmailTemplate/signUpV1
  • http://localhost:8787/renderEmailTemplate/signInV1
  • http://localhost:8787/renderEmailTemplate/orgInvitationV1

Testing

Run tests with Bun:

bun run test

Or in watch mode:

bun run test:w

Tests cover API rendering for login codes (extend for registration as needed).

Deployment to Cloudflare Workers

1. Login to Cloudflare:

   wrangler login
   

2. Configure Account ID (if needed, add to wrangler.toml):

   wrangler whoami
   

   Then update wrangler.toml with account_id = "your-account-id".

3. Deploy:

   bun run deploy
   

   (Or npx wrangler deploy.)

4. Monitor:

   wrangler tail email-generator-worker