Sending free transactional emails with Cloudflare Workers

While setting up authentication for https://dump.place, I realised that I needed to send emails to users.

I didn’t want to use a third-party service like SendGrid, Resend or Mailgun, because I didn’t want to pay for something that was not ‘mission-critical’ to the app, especially because it was just a side project.

I also didn’t want to set up my own email server, because that would be a lot of work, and I didn’t want to deal with the maintenance and security issues that come with running an email server.

So.. The best solution I found was to use Cloudflare Workers to send emails.

Wait, Cloudflare does that? 🤔

Yes. Cloudflare has been providing this service for a while, but it’s not very well known. They partnered with MailChannels for a way to provide users to send emails through cloudflare IP addresses.

Cloudflare IP Addresses

How do you send an email though a Cloudflare IP address? Using Cloudflare Workers, of course!

So, I found this github repository that acts as a proxy between your app and Cloudflare’s email service.

How to use it

Click this button

Follow the steps, it’s pretty straightforward.

Steps to deploy

Note: You’ll need to add your TOKEN variable in the wrangler.toml file, or you can add it in the Cloudflare dashboard. Just create a random, secure string and add it as a variable.

After you’ve deployed the worker, you can send an api request to the worker to send an email.

here’s the code from my nextauth file in dump.place

      async sendVerificationRequest({ identifier: email, url }) {
        await fetch("https://your-worker.workers.dev/api/email", {
          method: "POST",
          headers: {
            "Content-Type": "application/json",
            Authorization: `${env.EMAIL_TOKEN}`,
          },
          body: JSON.stringify({
            to: email,
            from: "Email Addr <your@cloudflare.domain>",
            subject: "Verify your email address.",
            text: `Welcome to my app. Click here to authenticate: ${url}`,
          }),
        });
      },

well… that was easy.

Yes, it was. I was surprised too. I thought it would be a lot more complicated, but it was pretty easy to set up.

Thx for reading this small (tutorial?) post. I hope you found it useful. If you did, share it! It helps me a lot.

NOTE:

Upon tweeting this blog, many pointed out the potential security issues with MailChannels. I’ll leave the tweets here

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