Email (SMTP)

With the mail feature, nest-api sends verification, welcome and password emails. Each is a BullMQ job on the mail queue, rendered from a React Email template in emails/ and sent over SMTP.

Variable	Value
SMTP_HOST	The server
SMTP_PORT	465 (TLS from the start) or 587 (STARTTLS). No other port validates
SMTP_SECURE	true for 465, false for 587
SMTP_USER, SMTP_PASSWORD	Credentials. Required and empty by default: the API won’t start until they’re set
SMTP_FROM	Shop <no-reply@shop.example>
SMTP_SUPPORT_EMAIL	Shown in the welcome email

Email is on the sign-up path

With mail on, email verification is mandatory: a new user can’t sign in until they click the link. If SMTP is broken, signups silently can’t complete. Watch the mail queue at /dashboard for failed jobs.

Locally

Run Mailpit, which accepts everything and shows it in a web inbox. Map it to port 587, since the API only accepts 465 or 587:

docker run -d --name mailpit -p 587:1025 -p 8025:8025 axllent/mailpit

SMTP_HOST='localhost'
SMTP_PORT='587'
SMTP_SECURE='false'
SMTP_USER='dev'
SMTP_PASSWORD='dev'

Sign up, open http://localhost:8025, and click the verification link. yarn email:dev previews the templates themselves on port 5003.

Production

Use a transactional provider (Postmark, Amazon SES, Mailgun, Resend, or your own server) on 587 with STARTTLS or 465 with TLS. Set up SPF, DKIM and DMARC for the SMTP_FROM domain, or verification emails land in spam.

Links in emails are built from SERVER_HOST and BETTER_AUTH_URL, so set those to public URLs before sending anything real.