SMTP Email

Send transactional emails through any SMTP-compatible relay server. Each synced row triggers an individual email to the recipient, making it ideal for personalized notifications, welcome sequences, and data-driven email campaigns.

Prerequisites

• Access to an SMTP server (e.g., Amazon SES, Mailgun, Postmark, or your own mail server)
• SMTP credentials: username and password with send permissions
• The SMTP server hostname and port number
• A verified sender email address (required by most SMTP providers)

Authentication

SMTP Email uses SMTP Credentials authentication (PLAIN auth over TLS).

1. Obtain SMTP credentials from your email provider
2. In Zeotap, enter your Username (often the sender email address)
3. Enter your Password (SMTP password or app-specific password)

Provider-Specific Notes

• Amazon SES: Use IAM SMTP credentials (not your AWS access keys). Generate them in the SES console under SMTP Settings.
• Gmail / Google Workspace: Use an App Password  — regular passwords will not work with 2FA enabled.
• Mailgun: Find SMTP credentials under Sending > Domain Settings > SMTP Credentials.
• Postmark: Use your Server API Token as both username and password.

Configuration

Target Settings

Template Placeholders

Both the subject and body fields support {{field_name}} placeholders that are replaced with values from each synced row. For example:

• Subject: Welcome, {{first_name}}!
• Body: <p>Hi {{first_name}} {{last_name}}, your account {{account_id}} is ready.</p>

Any mapped field can be used as a placeholder. Unknown placeholders are replaced with an empty string.

Supported Operations

Sync Modes

Audience Sync Modes

Features

• Field Mapping: Yes
• Schema Introspection: No

Required Mapping Fields

Default Destination Fields

email, first_name, last_name, name

How It Works

1. Zeotap establishes a single SMTP connection per batch to your configured server
2. For each row in the sync, an individual email is composed using the subject and body templates
3. Template placeholders ({{field_name}}) are replaced with the row’s mapped field values
4. The email is sent via the SMTP MAIL FROM / RCPT TO / DATA sequence
5. The connection is reused across all rows in the batch for efficiency
6. Failed sends are tracked per-row with the recipient address for troubleshooting

Batch Behavior

• Each row produces exactly one email — there is no batching or aggregation of recipients
• A single SMTP connection is reused for all emails in a batch
• Errors on individual emails do not stop the rest of the batch

Rate Limits

Rate limits depend on your SMTP provider:

Configure your Zeotap sync schedule to stay within your provider’s limits.

Best Practices

• Always use STARTTLS on port 587 for secure email delivery
• Verify your sender domain with SPF, DKIM, and DMARC records to improve deliverability
• Use app-specific passwords instead of your main account password when available
• Test with a small audience before sending to your full list
• Include an unsubscribe link in your email body to comply with CAN-SPAM and GDPR
• Monitor bounce rates — high bounce rates can damage your sender reputation

Troubleshooting

Connection refused or timed out

Verify the SMTP host and port are correct. Common ports: 587 (STARTTLS), 465 (implicit TLS), 25 (unencrypted). Some networks block port 25.

Authentication failed

Double-check your SMTP username and password. For Gmail, use an App Password. For Amazon SES, use SMTP-specific IAM credentials, not your AWS access key.

Emails not arriving

Check your provider’s sending logs for bounces or rejections. Verify the sender address is authorized in your SMTP provider. Check the recipient’s spam folder.

TLS handshake error

Enable the Use STARTTLS toggle if your server requires encryption on port 587. Port 465 is handled automatically — the connection upgrades to TLS before the SMTP greeting, so the STARTTLS toggle is ignored on that port.

Authentication refused without TLS

Zeotap refuses to send SMTP credentials over an unencrypted channel. Enable Use STARTTLS on port 587 or switch to port 465 (SMTPS). Plaintext PLAIN authentication is only permitted against a localhost relay.

Template placeholders not replaced

Ensure field names in {{placeholders}} match the mapped destination field names exactly (case-sensitive). Check that the fields are included in your field mapping configuration.

Rate limit exceeded

Your SMTP provider is rejecting emails due to sending too fast. Reduce your sync frequency or contact your provider to increase your sending quota.

Emails marked as spam

Configure SPF, DKIM, and DMARC records for your sending domain. Avoid spam trigger words in subject lines. Include a physical mailing address and unsubscribe link in the email body.