Setup & Configuration

Set up and configure Mailtrap email API and SMTP service and start sending emails in minutes.

Complete guide to setting up and configuring Mailtrap Email API/SMTP for your application. Follow these steps to start sending emails in production.

Quick start checklist

Get up and running with this essential setup checklist:

• Create your Mailtrap account
• Verify your sending domain
• Go to the Sending Setup page
• Choose integration method (API or SMTP)
• Configure authentication
• Send your first email

Important: Make sure the email address of the account owner is actively monitored. If we detect suspicious sending activity or need to clarify any important account details, we may contact you at this email address to ask additional questions, which helps avoid unnecessary account restrictions.

Furthermore, if your emails mention, promote, or link to another domain that belongs to you, your company, or your client, add that domain to Sending Domains and verify it as well. This helps us verify that the domains are connected to the same legitimate sender and prevents your emails from being mistaken for phishing. If you cannot add it due to the domains limit in your sending plan, please contact the support team for assistance.

Configuration steps

Sending Domain Setup

the foundation of email delivery. Verify your domain ownership and configure authentication records (SPF, DKIM, DMARC) for optimal deliverability.

API Integration

modern RESTful API for programmatic email sending. Best for new applications and microservices architecture.

SMTP Integration

traditional SMTP protocol for universal compatibility. Works with any email library or legacy system.

Dedicated IP

gradually build your sending reputation. Essential for high-volume senders and dedicated IPs.

Choose your integration method

When to use API

Best for:

• Modern web applications
• Microservices architecture
• Cloud-native applications
• Real-time sending needs
• Advanced analytics requirements

Advantages:

• Faster performance
• Better error handling
• Detailed response data
• Webhook support
• Easier debugging

Example:

curl -X POST "https://send.api.mailtrap.io/api/send" \
  -H "Authorization: Bearer YOUR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "from": {"email": "[e-mail]"},
    "to": [{"email": "[e-mail]"}],
    "subject": "Test Email",
    "text": "This is a test email"
  }'

When to use SMTP

Best for:

• Legacy applications
• Email clients
• CMS platforms
• Standard libraries
• Minimal code changes

Advantages:

• Universal compatibility
• No code changes required
• Works with any language
• Familiar protocol
• Easy migration