Backend developers: What's your go-to email service for large-scale applications?

Other Questions Mailgun
1

Hey there! I’m working on a big project and need some advice from experienced backend devs. We’re building a SaaS app that’ll handle about 100,000 emails a month for 10-20k users. I’m looking for a reliable email service that can do the usual stuff - welcome emails, password resets, invoices, and maybe newsletters.

I’ve checked out a bunch of options like Sendgrid, Postmark, and Resend, but I’m not sure which way to go. Nodemailer looks good 'cause it’s free, but I’m worried about emails ending up in spam folders.

What have you guys used before? Any recommendations based on your experience? I’d love to hear about the pros and cons you’ve run into.

Here’s a quick example of what I’m thinking for the welcome email function:

function sendWelcomeEmail(user) {
  const message = {
    to: user.email,
    subject: 'Welcome to Our App!',
    text: `Hi ${user.name}, thanks for joining us. We're excited to have you on board!`
  };
  return emailService.send(message);
}

Any thoughts on which service would work best for something like this? Thanks in advance for your help!

2

I’ve had great success with Amazon SES for large-scale applications. It’s cost-effective, highly scalable, and integrates seamlessly with other AWS services if you’re already in that ecosystem. The deliverability rates are excellent, and you can easily set up DKIM and SPF to improve inbox placement. One caveat: the initial setup can be a bit complex, especially if you’re not familiar with AWS. But once it’s running, it’s incredibly reliable. Just make sure to monitor your sending limits and reputation closely as you scale up. For your use case, SES should handle 100k emails/month without breaking a sweat.

3

I’ve been using SendGrid for a while now, and it’s been pretty solid for our high-volume needs. The API is straightforward, and their documentation is top-notch. We’re sending around 200k emails monthly, and it handles the load without breaking a sweat.

One thing I really appreciate is their analytics. You can track open rates, click-throughs, and even see which email clients your users are using. This has been super helpful for optimizing our email templates.

The only downside I’ve encountered is that their customer support can be a bit slow sometimes. But honestly, we haven’t needed to contact them much because everything just works.

For your welcome email function, SendGrid would work great. Just make sure to use their templating system - it’ll make your life so much easier when you need to update email content down the line.

Oh, and don’t forget to warm up your IP address gradually to build a good sender reputation. It’ll help ensure your emails land in the inbox, not the spam folder.

4

mailgun works well for my projects too. it’s reliable, delivers consistently, and their api is super easy. the free tier fits startps. just don’t forget to set up spf/dkim to prevent spam. documentation is solid.