Send Transactional Email

https://lumail.io/api/v1/emails

Send individual transactional emails directly to subscribers without creating a campaign. Perfect for welcome emails, password resets, order confirmations, and other automated communications.

Request Body

Field	Type	Required	Description
to	string	Yes	Email address to send the email to (subscriber will be created if doesn't exist)
subject	string	Yes	Email subject line
content	string	Yes	Email content (format depends on contentType)
contentType	string	No	Content format: MARKDOWN (default), HTML, or TIPTAP
preview	string	No	Email preview text shown in email clients
replyTo	string	No	Reply-to email address (must be valid email format)
from	string	Yes	Sender email address (domain must be verified)

Response

• Success (200 OK) - Email queued successfully for sending
• Error (400 Bad Request) - Invalid request data
• Error (401 Unauthorized) - Invalid or missing API token
• Error (404 Not Found) - Subscriber not found

Response Fields

Field	Type	Description
success	boolean	Indicates if the operation was successful
message	string	Success message
qstashMessageId	string	Unique ID for tracking the queued email

Content Types

Choose the format that best fits your use case:

Type	Description	Best For
MARKDOWN	Plain text with Markdown formatting (default)	Simple emails, quick integration
HTML	Raw HTML content	Full design control, existing templates
TIPTAP	Tiptap JSON format (same as Lumail editor)	Complex layouts, programmatic generation

See detailed documentation for each format:

• Send Email in Markdown
• Send Email in HTML
• Send Email in Tiptap

Email Content Format

The content field uses Markdown format. You can include various elements:

Basic Text

Hello {{name}}, this is a basic email.

Formatted Text

This is **bold text** and this is _italic text_.

Headings and Lists

# Welcome {{name}}!

## Benefits

- First benefit
- Second benefit
- Third benefit

### Getting Started

1. Step one
2. Step two
3. Step three

Links and Images

Visit our [website](https://example.com) for more information.

![Company Logo](https://example.com/logo.png)

Variable Substitution

You can use variables in your email content that will be automatically replaced with subscriber data:

• {{name}} - Subscriber's name
• {{email}} - Subscriber's email address
• {{phone}} - Subscriber's phone number
• {{unsubscribeUrl}} - Automatic unsubscribe link
• {{customField}} - Any custom field defined for the subscriber

Domain Verification

The from email address domain must be verified in your account. The API will:

1. Extract the domain from the from email address
2. Verify the domain is authorized and verified for your organization
3. Reject the request if the domain is not verified

Email Tracking

Transactional emails automatically include:

• Open tracking - Pixel tracking to detect email opens
• Click tracking - Link wrapping for click tracking
• Unsubscribe links - Automatic unsubscribe functionality
• Email storage - All sent emails are stored for analytics

Rate Limiting

Emails are queued and sent at a controlled rate to ensure deliverability:

• Rate: 14 emails per second
• Parallelism: 10 concurrent sends
• Queue: Emails are processed through QStash for reliability

Usage Examples

Welcome Email

Perfect for onboarding new users:

{
  "to": "newuser@example.com",
  "subject": "Welcome to {{companyName}}!",
  "content": "# Welcome {{name}}!\n\nThanks for joining us. Get started by exploring your dashboard.\n\n## Next Steps\n\n- Complete your profile\n- Explore our features\n- Join our community\n\nWe're excited to have you on board!",
  "from": "welcome@yourcompany.com",
  "preview": "Welcome to the platform"
}

Order Confirmation

For e-commerce order confirmations:

{
  "to": "customer@example.com",
  "subject": "Order Confirmation #{{orderNumber}}",
  "content": "## Thanks for your order, {{name}}!\n\nYour order #{{orderNumber}} has been confirmed and will be processed shortly.\n\n### Order Details\n\n- Order Number: {{orderNumber}}\n- Total: {{orderTotal}}\n- Shipping Address: {{shippingAddress}}\n\n**Estimated Delivery:** {{deliveryDate}}\n\nIf you have any questions, please don't hesitate to contact our support team.",
  "from": "orders@yourstore.com",
  "replyTo": "support@yourstore.com"
}

Password Reset

For password reset notifications:

{
  "to": "user@example.com",
  "subject": "Password Reset Request",
  "content": "Hi {{name}},\n\nYou requested a password reset for your account. Click the link below to reset your password:\n\n[Reset Password]({{resetUrl}})\n\n**This link will expire in 24 hours.**\n\nIf you didn't request this reset, please ignore this email or contact our support team if you have concerns.\n\nStay secure!",
  "from": "security@yourapp.com"
}

Error Handling

Common error responses:

Invalid Email Address

{
  "message": "Invalid email format"
}

Unauthorized Domain

{
  "message": "Domain 'example.com' is not authorized or verified for this organization"
}

Invalid Email Format

{
  "message": "Invalid from email address"
}

Validation Error

{
  "message": "Validation failed",
  "errors": [
    {
      "field": "subject",
      "message": "Subject is required"
    }
  ]
}

Related Documentation

• Variables - Personalize emails with subscriber data
• Content Deliverability Checker - Optimize emails before sending
• Email Domains Setup - Configure verified sending domains
• API Tokens - Generate API tokens for authentication
• Create Subscriber - Add subscribers to send emails to