GuideSMTP Relay

SMTP Relay Configuration

Learn how to obtain your SMTP credentials and configure your existing applications or servers to send transactional email through Simply Send.

Transactional emails only. SMTP relay is supported exclusively for transactional emails — system-triggered messages such as password resets, order confirmations, and account notifications. For marketing emails and campaigns, use the Marketing Email API instead.

Availability restrictions: SMTP relay access is enabled once your sender reputation is established. Verify your sending domain, complete your account setup, and send your first emails via the API to build a sending history before SMTP credentials become active.

1. Get Your SMTP Credentials

To start sending via SMTP, you'll need your unique SMTP credentials.

Log in to your Simply Send Dashboard.
Navigate to the SMTP on the left menu.
Create a new SMTP credentials. Keep this credentials secure.

2. Connection Settings

Use these settings in your email client, server configuration, or application code.

SMTP Host

smtp.domain.com

Port (STARTTLS)

587

Port (SSL/TLS)

465

Authentication

Required

3. Implementation Examples

swaks --server smtp.domain.com --port 587 \
  --auth plain --auth-user "your_account_id" \
  --auth-password "your_api_key" \
  --to recipient@example.com \
  --from sender@yourdomain.com \
  --header "Subject: Test with Swaks" \
  --body "Hello from Simply Send SMTP"

Security

We support both STARTTLS on port 587 and Implicit SSL/TLS on port 465. TLS 1.2 or higher is required for all connections.

Compliance

Ensure your emails include an unsubscribe link and physical address. Unlike the API, SMTP does not automatically inject these variables.