Regex to validate email: https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address
Email explained from first principles - https://explained-from-first-principles.com/email/
Falsehoods programmers believe about email - https://beesbuzz.biz/code/439-Falsehoods-programmers-believe-about-email - https://news.ycombinator.com/item?id=32671959
Why don’t we do email verification in reverse? - https://news.ycombinator.com/item?id=32537565
Dots don't matter in Gmail addresses - https://support.google.com/mail/answer/7436150
- Sent after the user performs an action, or some event occurs (eg a product ships).
- May be expected by the user.
- May not need to have an unsubscribe link.
There are two ways to send emails: SMTP or API.
- AWS SES (Simple Email Service): https://aws.amazon.com/ses/
- Mailchimp: https://mailchimp.com/features/transactional-email/
- Mailgun: https://www.mailgun.com/
- Postmark: https://postmarkapp.com/
- Sendgrid: https://sendgrid.com/