Bring Your Own SMTP (Custom SMTP)

TrekMail allows you to use your own SMTP provider (like Amazon SES, SendGrid, or Mailgun) to handle outbound mail. This gives you complete control over your sending reputation and limits.

Who this is for

• Free Plan Users: This is required to send outbound mail.
• High Volume Senders: If you need to send millions of emails cheaper than our plans allow.
• Developers: connecting to specific delivery pipelines.

How it works

This setting tells TrekMail: "When I send an email from Webmail or via the TrekMail API, relay it through this external server."

• Webmail: Uses these credentials to send.
• Desktop Clients (Outlook): You should usually enter your provider's SMTP settings directly into Outlook, bypassing TrekMail entirely for outbound efficiency.

Configuration Steps

1. Go to Sending & SMTP in the sidebar.
2. Select Bring Your Own SMTP.
3. Enter the details from your provider:
   • Hostname: (e.g., email-smtp.us-east-1.amazonaws.com)
   • Port: (usually 587 for TLS)
   • Username: (API User / SMTP User)
   • Password: (API Key / SMTP Password)
4. Click Save Configuration.

Provider Examples

Amazon SES

• Host: email-smtp.[region].amazonaws.com
• Port: 587 (STARTTLS)
• Username: SES SMTP Username (Not the IAM User Access Key)
• Password: SES SMTP Password (Not the IAM Secret Key)

SendGrid

• Host: smtp.sendgrid.net
• Port: 587
• Username: apikey (Literally the string "apikey")
• Password: Your actual SendGrid API Key starting with SG...

Mailgun

• Host: smtp.mailgun.org
• Port: 587
• Username: postmaster@your-domain.com
• Password: The SMTP password found in Domain Settings.

Common mistakes

• Symptom: "Connection Refused".
  • Cause: Using port 25 (often blocked). Use 587.
• Symptom: "Auth Failed" with AWS SES.
  • Cause: Using the IAM User Access Key instead of the SMTP credentials generated in the SES console. They are different.

See also

• Managed TrekMail SMTP
• Troubleshooting Sending Errors