SMTP Setup
MergeMail sends email through your own SMTP server. This means emails arrive from your domain, your sender reputation is preserved, and no third-party has access to your message content beyond transit.
Adding Your SMTP Configuration
- In the dashboard, go to Settings → SMTP.
- Fill in: Host, Port, Security, Username, Password, From Name, From Email, and optionally Reply-To.
- Click Test Connection. MergeMail will attempt to authenticate and send a test message to your own from-address.
- If the test succeeds, click Save Configuration.
Your SMTP password is encrypted with AES-256-GCM before being stored. It is never logged or displayed in plaintext.
Provider Guides
Gmail (Recommended: App Password)
| Host | smtp.gmail.com |
| Port | 587 |
| Security | STARTTLS |
| Username | your.email@gmail.com |
| Password | 16-character App Password (not your Google login password) |
To generate a Gmail App Password:
- Go to myaccount.google.com/security.
- Under "How you sign in to Google", enable 2-Step Verification if not already on.
- Search for "App Passwords" or navigate to Security → App Passwords.
- Select app "Mail" and device "Other". Name it "MergeMail".
- Copy the 16-character password generated and paste it into MergeMail.
Outlook / Hotmail
| Host | smtp-mail.outlook.com |
| Port | 587 |
| Security | STARTTLS |
| Username | your.email@outlook.com |
| Password | Your Outlook password (or App Password if MFA is enabled) |
Zoho Mail
| Host | smtp.zoho.com |
| Port | 587 (STARTTLS) or 465 (SSL) |
| Security | STARTTLS or SSL/TLS |
| Username | your.email@yourdomain.com |
| Password | Your Zoho Mail password |
Amazon SES
| Host | email-smtp.us-east-1.amazonaws.com (or your region) |
| Port | 587 |
| Security | STARTTLS |
| Username | SMTP Username from SES console (not your AWS Access Key ID) |
| Password | SMTP Password from SES console (not your AWS Secret Key) |
Note: Amazon SES requires you to verify your sender domain and, for new accounts, move out of the SES sandbox before sending to non-verified addresses.
Mailgun
| Host | smtp.mailgun.org |
| Port | 587 |
| Security | STARTTLS |
| Username | postmaster@yourdomain.mailgun.org |
| Password | Mailgun SMTP password from domain settings |
TLS Settings
MergeMail supports two TLS modes:
- STARTTLS (port 587): Connection starts unencrypted and upgrades to TLS. This is the modern recommended standard.
- SSL/TLS (port 465): Connection is encrypted from the start. Some older providers require this.
Do not use port 25 — it is blocked on most cloud platforms including Vercel, and is primarily used for server-to-server relay.
Testing Your SMTP
The Test Connection button on the SMTP settings page sends an authentication request to your SMTP server. A successful test means credentials are valid. It does not guarantee that every campaign email will be delivered (recipient-side filtering, rate limits, and spam scoring are outside MergeMail's control).