Nodemailer :: Nodemailer
Ethereal is a fake SMTP service, mostly aimed at Nodemailer and EmailEngine users (but not limited to). It's a completely free anti-transactional email service where messages never get delivered.
Instead, you can generate a vanity email account right from Nodemailer, send an email using that account just as you would with any other SMTP provider and finally preview the sent message here as no emails are actually delivered.
Ethereal addresses act as real IMAP/POP3 accounts. You can access sent and received messages using your favorite email client, whatever that happens to be.
Nodemailer :: Nodemailer