SendGrid email forwarding hook on free plan

I love the cost-effective solutions for the development. When I tried the email sending options provided by SendGrid, I found that the part of receiving email is included in the paid plans. So, using the SendGrid API with webhook want to forward the incoming emails to my favorite email account.

Create /api/sendgrid/mail-forwarding endpoint

Choose your best node.js framework (e.g.: express, next.js, nuxt.js, nest.js, …) and create a new endpoint with the name you want.

First, it was necessary to install a few packages (@sendgrid/mail, multer), that is, to add them to the project.

npm i @sendgrid/mail multer --save

Here is the TS code snippet, that I use to forward incomming emails to my personal email account.

// /sendgrid/mail-forwarding.ts
import sendGridMail from '@sendgrid/mail';
import multer from 'multer';

const SENDGRID_API_KEY = 'API_KEY'; // Use your own SendGrid api_key
const SENDGRID_TO_EMAIL = 'to@example.com'; // Use your personal email address to receive mails
const SENDGRID_FROM_EMAIL = 'from@example.com', // Use the email address or domain you verified on SendGrid

const initMiddleware = (middleware: any): => {
    return (req: Request, res: Response) =>
      new Promise((resolve, reject) => {
        middleware(req, res, (result: any) => {
            if (result instanceof Error) {
                return reject(result);
            }
            return resolve(result);
        });
    });
};

sendGridMail.setApiKey(SENDGRID_API_KEY!);

type ResponseData = {}

const upload = multer();
const multerAny = initMiddleware(
  upload.any(), // Note that Multer limits to 1MB file size by default
);

export default async (req: Request, res: Response<ResponseData>) => {
  if (req.method !== 'POST') {
    return res.status(405).json({});
  }

  await multerAny(req, res);

  const body = req.body;
  if (!body['text'] && !body['html']) {
    return res.status(400).json({});
  }

  const mailData: sendGridMail.MailDataRequired = {
    to: SENDGRID_TO_EMAIL,
    from: SENDGRID_FROM_EMAIL!,
    replyTo: body['from'],
    subject: body['subject'] ?? 'Forwarded email',
    text: body['text'],
    html: body['html'],
  };

  try {
    await sendGridMail.send(mailData);
  } catch (_error: any) {
    return res.status(500).json({});
  }

  res.status(200).json({});
}

SendGrid - Inbound Parse

Visit SendGrid / Settings page, here is the link. On the screen press the Add Host & URL and set the following options:

• Receiving Domain: // Choose your domain
• Destination URL: // Location of your deployed API endpoint
• Additional Options
  • SPAM CHECK ✅
  • SEND RAW ❌

Conclusion

For more than half a year now, this little email forwarding endpoint has been doing its job, I had no problem with hundreds of emails.