What are you using to send transactional emails?
And do you bother styling them? I’ve always used nodemailer/SES but making html email templates as a developer for hobby projects is a pain, keen to know what others use.
Can recommend Sendgrid, it can get expensive over time, but the the time trade off is worth initially plus basic styling is easy.
If you haven't already, you might wanna check out Sendgrid, Mailgun, Mandrill, etc.