Implementing an Email Delivery Service with Cloudflare Workers

 import { Hono } from "hono"
 import { cors } from "hono/cors"
 import { EmailMessage } from "cloudflare:email"
 import { createMimeMessage } from "mimetext"

 const worker = new Hono();

 // cors 
 worker.use('*', (c, next) => {
   const origins = c.env.ALLOWED_ORIGINS == '*' ? '*' : c.env.ALLOWED_ORIGINS.split(',');
   const corsMiddleware = cors(origins);
   return corsMiddleware(c, next);
 });

 // Mail sending interface, can be modified to any api you want
 worker.post('/send', async (c) => {
   const text = await c.req.text();
   const body = JSON.parse(text);
   if (!body['subject'] || !body['body']) {
     c.status(400)
     return c.json({
         "status": "error",
         "message": "Missing subject or body"
     })
   }

   const msg = createMimeMessage()
   msg.setSender({ name: c.env.SENDER_NAME, addr: c.env.SENDER_ADDRESS })
   msg.setRecipient(c.env.RECIPIENT_ADDRESS)
   msg.setSubject(body['subject'])
   msg.addMessage({
       contentType: 'text/html',
       data: body['body']
   })

   var message = new EmailMessage(
       c.env.SENDER_ADDRESS,
       c.env.RECIPIENT_ADDRESS,
       msg.asRaw()
   );

   try {
       // The SEB here comes from the send_email configuration in wrangler.toml
       await c.env.SEB.send(message)
   } catch (e) {
       c.status(500)
       return c.json({
           "status": "error",
           "message": "Email failed to send",
           "error_details": e.message
       });
   }

   return c.json({
       "status": "success",
       "message": "Email sent successfully"
   });

 });

 export default worker;

 # The name configuration here corresponds to c.env.SEB.send in the code, which needs to be synchronized.
 send_email = [
     {type = "send_email", name = "SEB", destination_address = "xxx"},
 ]

 [vars]
 ALLOWED_ORIGINS = "*"
 RECIPIENT_ADDRESS = "*"
 SENDER_ADDRESS = "*"
 SENDER_NAME = "*"

$ npm install -g wrangler
$ wrangler login
$ wrangler deploy

fetch('https://example.workers.dev/send', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    subject: 'subject',
    body: 'email content'
  })
})