I always use Mailgun + Laravel Notification system. I write the email templates with Markdown or Blade.<p>How do you implement your transactional email system if you use other languages/frameworks?
<a href="https://postmarkapp.com/" rel="nofollow">https://postmarkapp.com/</a> who do only transactional emails and there's no free plan. The account isn't even complete setup until you've send an email via their API and a customer service person has reviewed your setup. It's extra steps but we found their delivery rates better than sendgrid/mailgun in the past. We have the email templates in our Ruby framework (Rails) with some inline CSS (based on <a href="https://github.com/mailgun/transactional-email-templates" rel="nofollow">https://github.com/mailgun/transactional-email-templates</a>).