>_SMTPBoxDOCUMENTATION

SMTP server settings: ports, TLS and credentials

Connect to smtp.smtpbox.dev using STARTTLS on 587 or 2525, or implicit TLS on 465, with inbox credentials.

03 / SEND

SMTP connection settings

Use an inbox credential—not your SMTPBox sign-in password and not an API key. Each credential routes mail to the inbox selected when it was generated.

Environment variables
SMTP_HOST=smtp.smtpbox.dev
SMTP_PORT=587
SMTP_USERNAME=sb_your_inbox_username
SMTP_PASSWORD=your_one_time_password
SMTP_ENCRYPTION=tls
RECOMMENDED

Port 587 or 2525

Connect normally, then upgrade with STARTTLS before authenticating.

ALTERNATIVE

Port 465

Use implicit TLS—the connection is encrypted from its first byte.

Credential hygiene

Store credentials in environment variables or your CI secret store. If a password is lost or exposed, revoke that credential and generate another. Existing credentials are never revealed again.

Updated